Patent Description:
Sterile barrier assemblies such as surgical drapes are known for establishing barriers between surgical components during surgery. For instance, a surgical drape may be used to provide a barrier between a robotic arm and an end effector attached to the robotic arm. In surgery, the robotic arm is treated as being nonsterile, while the end effector is sterile. The surgical drape creates a barrier between the robotic arm and the end effector to prevent contamination of a sterile field in which the end effector is operating.

Typically, surgical drapes placed between the robotic arm and the end effector have perforations or other openings through which different connections can be made between the robotic arm and the end effector, such as mechanical connections and/or electrical connections. Such perforations are acceptable, so long as they are covered during the surgery. If the end effector fails during the surgery and needs to be replaced, or if a different end effector is desired, and the perforations become uncovered, standard operating room sterility protocol may dictate that the surgical drape requires replacement before a different end effector can be installed. Removal of the surgical drape and installation of a new surgical drape takes up valuable time, so replacement is undesirable.

Other surgical drapes are not intentionally perforated, but instead are compressed between the robotic arm and the end effector. When compressed, if the surgical drape is formed of thin plastic, unintended rips or tears may occur. Even when the surgical drape does remain intact, positioning of the end effector on the robotic arm is imprecise as a result of the compressibility of the surgical drape. For example, the surgical drape may compress unequally. Further, a thick drape made out of conventional draping materials could deflect under normal end effector loads. Small deflections are magnified out to a tool center point (TCP) of the end effector and can become intolerable due to errors in positioning accuracy of the TCP.

Therefore, there is a need in the art for addressing one or more of these deficiencies.

Document <CIT>shows a sterile drape for covering a robotic surgical manipulator, the sterile drape comprising a sterile sheet and an instrument interface that covers a drive plate of the robotic surgical manipulator.

Document <CIT> describes a sterile drape with a sterile surgical adapter to be used with a manipulator assembly, said sterile adapter providing mounting means for mounting a surgical instrument to the manipulator assembly so as to be moved by the manipulator system and to transfer electrical signals, while maintaining a sterile barrier between the sterile surgical field and the non-sterile robotic system.

The sterile barrier assembly according to the invention is defined in claim <NUM>.

In one embodiment and according to claim <NUM> a sterile barrier assembly is provided for establishing a barrier between first and second surgical components during a surgery. The assembly includes a protective covering having and interface including a plurality of kinematic couplers integrated therein to provide a kinematic coupling between the first and second surgical components through the protective covering. The protective covering further includes a drape attached to the interface. The plurality of kinematic couplers are further defined as a plurality of balls, and the interface includes a load element adapted to receive a preload force for preloading the kinematic coupling between the surgical components.

In another exemplary embodiment a mounting system for coupling first and second surgical components is provided. The system includes a first mounting portion for the first surgical component and a second mounting portion for the second surgical component. The system also includes a protective covering having a plurality of kinematic couplers to kinematically couple the first and second mounting portions through the protective covering.

A method is provided in yet another exemplary embodiment for coupling first and second surgical components. The method includes placing a sterile barrier assembly having a plurality of kinematic couplers on the first surgical component. The method further includes placing the second surgical component on the sterile barrier assembly. The method further includes preloading a preload element to kinematically couple the surgical components together via the plurality of kinematic couplers through the sterile barrier assembly.

One advantage of the sterile barrier assembly, mounting system, and method is the ability to kinematically couple the first surgical component to the second surgical component through the sterile barrier assembly so that positioning is repeatable and deterministic while keeping the sterile barrier assembly intact.

Referring to <FIG> and <FIG>, a mounting system <NUM> is shown for kinematically coupling first and second surgical components using a sterile barrier assembly <NUM>. In one embodiment described herein, the first surgical component is a robotic arm R and the second surgical component is an end effector EE for the robotic arm R. It should be appreciated that the mounting system <NUM> can be employed to kinematically couple any surgical components using the sterile barrier assembly <NUM>.

The robotic arm R includes a first mounting portion <NUM> and the end effector EE includes a second mounting portion <NUM>. The sterile barrier assembly <NUM> is located between the first and second mounting portions <NUM>, <NUM> to establish a barrier between the robotic arm R and the end effector EE during surgery. This barrier separates the robotic arm R from a sterile field S in which the end effector EE is operating. During surgery, the robotic arm R is considered nonsterile and the barrier reduces the potential for migration of contaminants from the robotic arm R into the sterile field S.

The mounting portions <NUM>, <NUM> are kinematically coupled together using the sterile barrier assembly <NUM>. Kinematic coupling provides a rigid connection between the mounting portions <NUM>, <NUM> so that positioning between the mounting portions <NUM>, <NUM> can be deterministic and repeatable. As a result of this rigid, deterministic and repeatable connection, errors in positioning the end effector EE that may otherwise be associated with a more flexible connection can be reduced.

Kinematic coupling exactly constrains the number of degrees of freedom that are to be constrained, i.e., no degree of freedom is overconstrained. For instance, in one embodiment there are six degrees of freedom between the mounting portions <NUM>, <NUM>, e.g., three translational and three rotational. Thus, kinematic coupling constrains exactly those six degrees of freedom.

Referring to <FIG> and <FIG>, a plurality of kinematic couplers (also referred to as kinematic elements) of the sterile barrier assembly <NUM> are used to kinematically couple the mounting portions <NUM>, <NUM>. In the embodiment shown, the kinematic couplers are spherical balls <NUM>. During use, the balls <NUM> are seated in first and second pluralities of receptacles <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> of the mounting portions <NUM>, <NUM>. The receptacles <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> are sized and shaped to receive the balls <NUM>. In the embodiment shown, the first mounting portion <NUM> includes a first body <NUM> and a first cover plate <NUM> fixed to the first body <NUM>. The first plurality of receptacles <NUM>, <NUM>, <NUM> are fixed in the first cover plate <NUM>. The second mounting portion <NUM> includes a second body <NUM> and a second cover plate <NUM> fixed to the second body <NUM>. The second plurality of receptacles <NUM>, <NUM>, <NUM> are fixed in the second cover plate <NUM>.

Referring to <FIG> and <FIG>, the first plurality of receptacles <NUM>, <NUM>, <NUM> includes one receptacle <NUM> having a contact surface <NUM> with a conical configuration (also referred to as a cone receptacle). Another receptacle <NUM> has a pair of contact surfaces <NUM> provided by a V-shaped groove (also referred to as a V-grooved receptacle). Yet another receptacle <NUM> has a contact surface including a flat <NUM> (also referred to as a planar receptacle). The second plurality of receptacles <NUM>, <NUM>, <NUM> includes three receptacles having contact surfaces <NUM> with conical configurations (i.e., cone receptacles). Three balls <NUM> are captured between corresponding, aligned pairs of the receptacles, i.e., receptacle <NUM> to receptacle <NUM>, receptacle <NUM> to receptacle <NUM>, and receptacle <NUM> to receptacle <NUM>, as shown in <FIG> and <FIG>. The contact surfaces <NUM>, <NUM>, <NUM>, <NUM> of the receptacles <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> act as constraint surfaces for the kinematic coupling described herein.

The receptacles <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may be formed of steel or other suitably rigid materials and may be separate components rigidly connected to the cover plates <NUM>, <NUM> or may be integral with the cover plates <NUM>, <NUM>. The receptacles <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may be integrated into the mounting portions <NUM>, <NUM>, in which case the receptacles <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> simply comprise constraint surfaces integral with the mounting portions <NUM>, <NUM> for securing the balls <NUM>, or the receptacles <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may otherwise be attached to the mounting portions <NUM>, <NUM> in numerous ways via numerous structures.

When the mounting portions <NUM>, <NUM> are brought together in approximate final orientation with the sterile barrier assembly <NUM> positioned therebetween, the balls <NUM> of the sterile barrier assembly <NUM> self-seat into the receptacles <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. The cone receptacle, V-grooved receptacle, and planar receptacle of the first mounting portion <NUM> remove, three, two, and one degrees of freedom, respectively, via three, two, and one points of contact with the balls <NUM>. Thus, exactly six degrees of freedom are constrained. In other embodiments, described further below, each of the first plurality of receptacles <NUM>, <NUM>, <NUM> of the first mounting portion <NUM> may remove two degrees of freedom via two points of contact with the balls <NUM>. In either of these cases, exactly six degrees of freedom are constrained via exactly six contact points, e.g., one contact point for each degree of freedom.

Referring to <FIG> and <FIG>, the sterile barrier assembly <NUM> includes a protective covering <NUM>. The protective covering <NUM> includes an interface <NUM> and a drape <NUM> attached to the interface <NUM>. The drape <NUM> has an interior surface and an exterior surface. The interior surface is placed adjacent to the robotic arm R during surgery. In the embodiment shown the drape <NUM> is fitted to the robotic arm R to generally encompass the robotic arm R. The drape <NUM> is formed of at least one of polyethylene, polyurethane, and polycarbonate. The drape <NUM> may be attached to the interface <NUM> by ultrasonic welding, tape, adhesive, or the like. The drape <NUM> is attached to the interface <NUM> so that no perforations are present, i.e., the drape forms a continuous barrier with the interface <NUM>.

In the embodiment shown, the interface <NUM> is formed of molded plastic material. The interface <NUM> may be formed of rubber, silicone, urethane, or other suitable materials. The interface <NUM> includes a main wall <NUM> having a perimeter and a peripheral wall <NUM> joining the main wall <NUM> at the perimeter. The peripheral wall <NUM> may be generally perpendicular to the main wall <NUM>, but preferably flares slightly outwardly from perpendicular to define a cavity <NUM> for receiving the first mounting portion <NUM>. The drape <NUM> is attached to the peripheral wall <NUM> of the interface <NUM> (See <FIG>). The drape <NUM> is absent in <FIG>, <FIG>, and <FIG> to better illustrate other components.

The main wall <NUM> has a plurality of separated support sections <NUM>, <NUM>, <NUM>, <NUM> having a larger thickness. The main wall <NUM> has a width of from about <NUM>,<NUM> (<NUM> inches) to about <NUM>,<NUM> (<NUM> inches) between the support sections <NUM>, <NUM>, <NUM>, <NUM> and a width of from about <NUM>,<NUM> (<NUM> inches) to about <NUM>,<NUM> (<NUM> inches) at the support sections <NUM>, <NUM>, <NUM>, <NUM>. The main wall <NUM> has a Durometer of Shore A <NUM>.

The interface <NUM> includes the balls <NUM> integrated therein. In one embodiment, the balls <NUM> are insert molded in three of the support sections <NUM>, <NUM>, <NUM>. As described above, the balls <NUM> are arranged for receipt in the first and second plurality of receptacles <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> to kinematically couple the first and second mounting portions <NUM>, <NUM>. The balls <NUM> are located so that the barrier remains unbroken between the support sections <NUM>, <NUM>, <NUM> and the balls <NUM> to reduce the potential for migration of contaminants through the interface <NUM>. Thus, the drape <NUM> and the interface <NUM> provide a continuous barrier to the migration of contaminants from the robotic arm R into the sterile field S.

In one embodiment, the balls <NUM> have polished, corrosion-resistant surfaces, so that under certain loads submicron repeatability in positioning the mounting portions <NUM>, <NUM> can be achieved. The balls <NUM> may be formed of ceramic, stainless steel, or other suitable materials. The balls <NUM> may be formed of silicon carbide or tungsten carbide. The balls <NUM> may be precision machined to very tight tolerances, for example less than <NUM>,08e-<NUM> cm (fifty millionths of an inch).

The interface <NUM> includes a plurality of electrical terminals. In the embodiment shown, the electrical terminals are pins <NUM> that may be insert molded into the main wall <NUM>. The pins <NUM> are located so that the barrier remains unbroken between the main wall <NUM> and the pins <NUM> to reduce the potential for contaminants to migrate through the interface <NUM>. The pins <NUM> transfer electrical power/signals across the sterile barrier assembly <NUM>.

The interface <NUM> includes a preloading element. In the embodiment shown, the preloading element is an elongated load bar <NUM>. The load bar <NUM> may be insert molded into one of the support sections. The load bar <NUM> is formed with rounded indentations on sides thereof to facilitate embedding in the support section so that the load bar <NUM> remains fixed to the interface <NUM> during use. The load bar <NUM> is located such that the barrier remains unbroken between the support section and the load bar <NUM> to reduce the potential for migration of contaminants through the interface <NUM>. Thus, the drape <NUM> and interface <NUM> provide a continuous barrier to the migration of contaminants from the robotic arm R into the sterile field S.

The load bar <NUM> has first and second ends. The load bar <NUM> may be formed of stainless steel, Kevlar composite, or other suitably rigid materials. The load bar <NUM> defines apertures <NUM> near each of the ends. Inserts <NUM> are located in the apertures <NUM>. The inserts <NUM> are in the form of cylindrical bushings. The inserts <NUM> are formed of stainless steel or silicone nitride. In some embodiments, the load bar <NUM> is employed without inserts.

Referring to <FIG>, a preloading mechanism <NUM> clamps the mounting portions <NUM>, <NUM> in position once they are brought together in approximate final orientation. In the embodiment shown, the load bar <NUM> forms part of the preloading mechanism <NUM> and also acts as an initial support member to hold the protective covering <NUM> on the robotic arm R. A preload force is applied to the load bar <NUM>. The preload force is sized to exceed anticipated loading through the kinematic coupling so that the kinematic coupling and associated properties are maintained.

The preloading mechanism <NUM> further includes a first catch <NUM>. The first catch <NUM> is slidably disposed in a catch guide <NUM> to move from an unlatched position to a latched position. The catch guide <NUM> is held in a first inner cavity <NUM> (see <FIG>) defined in the first body <NUM>. The catch guide <NUM> defines an oblong through passage <NUM> in which the first catch <NUM> slides.

As shown in <FIG>, a first spring <NUM> biases the first catch <NUM> laterally from a side wall <NUM> of the first body <NUM> into the latched position. A first release button (not shown) can be slidably disposed in the first body <NUM> to release the first catch <NUM>. The first release button may simply be depressed to slide the first catch <NUM> from the latched position to the unlatched position.

A load bar receiver <NUM> defines another oblong passage <NUM>. The oblong passages <NUM>, <NUM> of the catch guide <NUM> and the receiver <NUM> align with one another so that the first catch <NUM> is slidable therein to move from the unlatched position to the latched position. The receiver <NUM> is cylindrical. The receiver <NUM> further defines a load bar slot <NUM> therethrough. The load bar slot <NUM> is arranged perpendicularly to the oblong passage <NUM> in the receiver <NUM> to receive the first end of the load bar <NUM>.

During use, the first end of the load bar <NUM> is inserted into the load bar slot <NUM> until one of the apertures <NUM> in the load bar <NUM> is engaged by the first catch <NUM> (see <FIG> and <FIG>). Once the load bar <NUM> is fully engaged by the first catch <NUM>, the sterile barrier assembly <NUM> is generally supported on the first mounting portion <NUM> for further manipulation. Thus, the load bar <NUM> and the first catch <NUM> function as an initial support mechanism for the sterile barrier assembly <NUM>.

Referring to <FIG> and <FIG>, the preloading mechanism <NUM> further includes a second catch <NUM>. The second catch <NUM> is slidably disposed in the second body <NUM>. More specifically, the second mounting portion <NUM> defines a second inner cavity <NUM> in which the second catch <NUM> is slidable between unlatched and latched positions.

A second spring <NUM> biases the second catch <NUM> laterally from a side wall <NUM> of the second body <NUM> into the latched position. A second release button <NUM>, like the first, can be slidably disposed in the second body <NUM> to release the second catch <NUM>. The second release button <NUM> may simply be depressed to slide the second catch <NUM> from the latched position to the unlatched position.

The second cover plate <NUM> fixed to the second body <NUM> has an elongated slot <NUM> (see <FIG>) sized to receive the second end of the load bar <NUM> opposite the first end inserted into the receiver <NUM>.

During use, the second end of the load bar <NUM> is inserted into the elongated slot <NUM> until the other aperture <NUM> in the load bar <NUM> is engaged by the second catch <NUM>. Once the load bar <NUM> is fully engaged by the second catch <NUM>, the sterile barrier assembly <NUM> and the second mounting portion <NUM> are generally supported on the first mounting portion <NUM> for further installation. Thus, the load bar <NUM>, the first catch <NUM>, and the second catch <NUM> also function as a support mechanism for the sterile barrier assembly <NUM> and the second mounting portion <NUM>.

As shown in <FIG>, the preloading mechanism further includes a tensioner <NUM> operatively coupled to the load bar <NUM>. The tensioner <NUM> applies tension to the load bar <NUM> and clamps the first and second mounting portions <NUM>, <NUM> together with the preload force such that the balls <NUM> seat into the first and second plurality of receptacles <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>.

Referring to <FIG>, the tensioner <NUM> applies tension to the load bar <NUM> by moving the second catch <NUM> with respect to the first catch <NUM>. The second catch <NUM>, while slidable in the second body <NUM> between unlatched and latched positions, is also pivotally supported in the second body <NUM> about a pivot shaft <NUM>. The pivot shaft <NUM> is located in a pair of support bores <NUM>, <NUM> in the second body <NUM>. The second catch <NUM> defines a pivot bore <NUM> (see <FIG>) therethrough for receiving the pivot shaft <NUM>. As a result, the second catch <NUM> is able to pivot about the pivot shaft <NUM>.

The tensioner <NUM> includes a cam shaft <NUM>. The cam shaft <NUM> is rotatable between tensioned and untensioned positions. The cam shaft <NUM> is rotatably supported in a pair of support bores <NUM>, <NUM> in the second body <NUM>. The cam shaft <NUM> has first and second cylindrical shaft sections <NUM>, <NUM> that are rotatably supported in the support bores <NUM>, <NUM> by bushings <NUM>.

The cam shaft <NUM> includes a cam section <NUM> (see <FIG> and <FIG>) between the first and second shaft sections <NUM>, <NUM>. The cam section <NUM> is offset from the first and second shaft sections <NUM>, <NUM>. The cam section <NUM> is disposed in a cam passage <NUM> defined in the second catch <NUM> (see <FIG>). The cam passage <NUM> is rectangular in shape and extends through the second catch <NUM> near one end of the second catch <NUM>, while the pivot bore <NUM> extends through the second catch <NUM> near an opposite end. When the cam shaft <NUM> begins rotation toward the tensioned position, the cam section <NUM> contacts an inner surface <NUM> defining the cam passage <NUM>. Further rotation of the cam shaft <NUM> causes additional camming action by the cam section <NUM> against the inner surface <NUM> which pivots the second catch <NUM> about the pivot shaft <NUM> so that tension is placed on the load bar <NUM>.

The tensioner <NUM> also includes a lever <NUM> rotatably fixed to the cam shaft <NUM> via a lever attachment <NUM>. The lever attachment <NUM> has a geometric shape that conforms to a shape of a cavity (not shown) in the lever <NUM> so that actuation of the lever <NUM> results in rotation of the cam shaft <NUM>. The cam shaft <NUM> is rotated at least ninety degrees to move between the untensioned and tensioned positions. Of course, other positions therebetween may place tension on the load bar <NUM> and could be suitable for applying the desired preload force.

The lever <NUM> is locked when the cam shaft <NUM> is placed in the desired position, e.g., the tensioned position. In the tensioned position, the preload tensile force is applied to the load bar <NUM>. By locking the lever <NUM> after applying the preload force, the preload force is continually applied during use of the robotic arm R and end effector EE to maintain the kinematic coupling. The preloading mechanism <NUM> transfers the preload force across the sterile barrier assembly <NUM> without piercing the barrier.

When the tensioner <NUM> applies the preload force to the load bar <NUM>, a disc spring <NUM> applies a compressive force equal to the preload force to the load bar <NUM>. The disc spring <NUM> is contained between two spring shims <NUM>. The disc spring <NUM> biases the catch guide <NUM>, receiver <NUM>, and first catch <NUM> toward a rear wall <NUM> of the first body <NUM>. The disc spring <NUM> biases the load bar <NUM> by virtue of the load bar <NUM> being latched to the first catch <NUM>.

As the balls <NUM> are aligned within the first and second plurality of receptacles <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and the preload force is applied, some stretching and/or flexing of the interface <NUM> is possible between the balls <NUM> so that the balls <NUM> properly seat in the receptacles <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, particularly when the second plurality of receptacles <NUM>, <NUM>, <NUM> have conical configurations (which engage each of the balls <NUM> at three contact points). This stretching and/or flexing occurs without breaking the barrier. Thus, the balls <NUM> are able to move into the receptacles <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> upon preloading. These properties of the interface <NUM> account for manufacturing tolerances. In other words, the interface <NUM> is able to stretch and/or flex without breaking contact or a seal with the balls <NUM>, such as the contact or seal created during molding.

Once seated, positions of the balls <NUM> are fixed relative to the first and second plurality of receptacles <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. As a result, the first and second mounting portions <NUM>, <NUM> are kinematically coupled together without piercing the sterile barrier assembly <NUM>. The kinematic coupling allows the end effector EE to be readily released from and rejoined to the robotic arm R at the same location. The kinematic coupling also allows the end effector EE to be readily released from the robotic arm R so that different end effectors with similar mounting portions can be kinematically coupled to the robotic arm R.

<FIG> shows electrical power and/or other signal connections that can be made through the sterile barrier assembly <NUM>. These connections employ the pins <NUM>. These pins <NUM> electrically interconnect electrical connectors attached to the first and second mounting portions <NUM>, <NUM>.

In the embodiment shown in <FIG>, <FIG>, and <FIG>, the first mounting portion <NUM> includes a first electrical connector base <NUM>. The first electrical connector base <NUM> is fixed in a communication cavity <NUM> defined in the first body <NUM>. The first cover plate <NUM> defines an opening <NUM> into the communication cavity <NUM>. A wireway <NUM> is also defined in the first body <NUM> to carry wires away from the first electrical connector base <NUM>. A plurality of pogo pin connectors <NUM>, e.g., spring-loaded electrical connectors, are movably supported by the first electrical connector base <NUM>.

The second mounting portion <NUM> includes a second electrical connector base <NUM>. The second electrical connector base <NUM> is fixed in an opening <NUM> in the second cover plate <NUM>. A plurality of electrical receiver terminals <NUM> are supported by the second electrical connector base <NUM>. When the first and second mounting portions <NUM>, <NUM> are kinematically coupled together and preloaded, the electrical receiver terminals <NUM> receive the pins <NUM> of the interface <NUM>. Likewise, the pogo pin connectors <NUM> make contact with the pins <NUM> of the interface <NUM> so that power or other electrical signals can flow through the pins <NUM>. Thus, power, communication signals, or other signals can be passed from the robotic arm R to the end effector EE and vice versa.

Referring to <FIG>, an alternative mounting system <NUM> is shown for kinematically coupling the first and second surgical components (e.g., robotic arm R and end effector EE) using a sterile barrier assembly <NUM>.

In this embodiment, the robotic arm R includes a first mounting portion <NUM> and the end effector EE includes a second mounting portion <NUM>. The sterile barrier assembly <NUM> is located between the first and second mounting portions <NUM>, <NUM> to establish the barrier between the robotic arm R and the end effector EE during surgery.

Referring to <FIG> and <FIG>, a plurality of kinematic couplers are used to kinematically couple the first and second mounting portions <NUM>, <NUM>. In this embodiment, the kinematic couplers are spherical balls <NUM>. The balls <NUM> are seated in first and second pluralities of receptacles <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. The receptacles <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> are sized and shaped to receive the balls <NUM>. The first mounting portion <NUM> includes a first body <NUM> and a first cover plate <NUM> fixed to the first body <NUM>. The first plurality of receptacles <NUM>, <NUM>, <NUM> are fixed in the first body <NUM>. The second mounting portion <NUM> includes a second body <NUM>. The second plurality of receptacles <NUM>, <NUM>, <NUM> are fixed in the second body <NUM>.

Referring to <FIG>, the first plurality of receptacles <NUM>, <NUM>, <NUM> includes one receptacle <NUM> having a contact surface <NUM> with a conical configuration (also referred to as a cone receptacle). Another receptacle <NUM> has a pair of contact surfaces <NUM> provided by a V-shaped groove (also referred to as a V-grooved receptacle). Yet another receptacle <NUM> has a contact surface <NUM> including a flat (also referred to as a planar receptacle). The contact surfaces <NUM> of the V-grooved receptacle or the contact surface <NUM> of the planar receptacle may be generally flat or may be concave with the surfaces <NUM>, <NUM> having a concavity that results in only a single point of contact with the balls <NUM>. In some versions, the contact surfaces <NUM> of the V-grooved receptacle are in the shape of a gothic arch.

The second plurality of receptacles <NUM>, <NUM>, <NUM> includes three receptacles having contact surfaces <NUM> with conical configurations (i.e., cone receptacles). Three balls <NUM> are captured between corresponding, aligned pairs of the receptacles, i. e, receptacle <NUM> to receptacle <NUM>, receptacle <NUM> to receptacle <NUM>, and receptacle <NUM> to receptacle <NUM>, as shown in <FIG>.

The receptacles <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may be formed of steel or other suitably rigid materials and may be separate components rigidly connected to the bodies <NUM>, <NUM> or may be integral with the bodies <NUM>, <NUM>. The receptacles <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may be integrated into the mounting portions <NUM>, <NUM> or otherwise attached to the mounting portions <NUM>, <NUM> in numerous ways.

When the mounting portions <NUM>, <NUM> are brought together in approximate final orientation with the sterile barrier assembly <NUM> positioned therebetween, the balls <NUM> of the sterile barrier assembly <NUM> self-seat into the receptacles <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. The cone receptacle, V-grooved receptacle, and planar receptacle of the first mounting portion <NUM> remove, three, two, and one degrees of freedom, respectively. Thus, exactly six degrees of freedom are constrained. In other embodiments, described further below, each of the first plurality of receptacles <NUM>, <NUM>, <NUM> of the first mounting portion <NUM> may remove two degrees of freedom via two points of contact with the balls <NUM>. In either of these cases, exactly six degrees of freedom are constrained via exactly six contact points, e.g., one contact point for each degree of freedom.

Referring to <FIG>, the sterile barrier assembly <NUM> includes a protective covering <NUM>. The protective covering <NUM> includes an interface <NUM> and a drape <NUM> attached to the interface <NUM>. The drape <NUM> has an interior surface and an exterior surface. The interior surface is placed adjacent to the robotic arm R during surgery. In this embodiment, the drape <NUM> is fitted to the robotic arm R to generally encompass the robotic arm R. The drape <NUM> is formed of at least one of polyethylene, polyurethane, and polycarbonate. The drape <NUM> may be attached to the interface <NUM> by ultrasonic welding, tape, adhesive, or the like. The drape <NUM> is attached to the interface <NUM> so that no perforations are present or are sealed, i.e., the drape forms a continuous barrier with the interface <NUM>. The drape <NUM> is absent in <FIG> and <FIG> to better illustrate other components.

Referring to <FIG> and <FIG>, in the embodiment shown, the interface <NUM> includes a latch bracket <NUM> formed of a rigid material such as aluminum or stainless steel. The latch bracket <NUM> includes a main wall <NUM> (see <FIG>) having a perimeter and an inner wall <NUM> extending from the main wall <NUM>. The inner wall <NUM> may be generally perpendicular to the main wall <NUM>. The latch bracket <NUM> includes a pair of latches <NUM> (see also <FIG>) extending from the main wall <NUM> in a direction opposite the inner wall <NUM>. The latches <NUM> may be in the form of latch hooks. The latches <NUM> interact with and engage a first catch <NUM> of the first mounting portion <NUM> as described below.

The interface <NUM> further includes a cover <NUM> having a peripheral lip <NUM>. The cover <NUM> may be formed of injection molded plastic. The peripheral lip <NUM> snap-fits over the main wall <NUM> so that the cover <NUM> is secured to the latch bracket <NUM>. When secured, the cover <NUM> includes an outer wall <NUM> surrounding the inner wall <NUM> of the latch bracket <NUM>. The cover <NUM> also includes a wall <NUM>. The wall <NUM> extends from a base of the outer wall <NUM> to the peripheral lip <NUM>. In addition to the snap-fit connection, the cover <NUM> may be fixed to the latch bracket <NUM> by adhesive between the wall <NUM> and the main wall <NUM> of the latch bracket <NUM>. A seal (not shown) may be located between an edge of the main wall <NUM> and an inner edge of the peripheral lip <NUM> to further enhance the barrier.

The peripheral lip <NUM> defines an attachment groove <NUM> in which the drape <NUM> is attached to the interface <NUM>. The attachment groove <NUM> may receive, for example, an elastic band of the drape <NUM>, tape for the drape <NUM>, a snap-ring of the drape <NUM>, and the like.

The interface <NUM> includes the balls <NUM> integrated therein. In this embodiment, the balls <NUM> are located in ball openings defined in the main wall <NUM> of the latch bracket <NUM>. The ball openings are sized so that a portion of each of the balls <NUM> protrudes on either side of the main wall <NUM>. The main wall <NUM> includes a stop <NUM> in each of the ball openings. In the embodiment shown, the stop <NUM> is a radially inwardly directed tapered surface of the main wall <NUM>. The tapered surface defines an opening having a diameter slightly smaller than a diameter of the balls <NUM> to prevent the balls <NUM> from passing entirely through the main wall <NUM> (see <FIG>).

During assembly the balls <NUM> are dropped into the ball openings in the main wall <NUM>. The stop <NUM> prevents the balls <NUM> from passing entirely through the ball openings while still allowing a portion of the balls <NUM> to protrude beyond the main wall <NUM>. The cover <NUM> is then snap-fit over the latch bracket <NUM> to hold the balls <NUM> in place in the ball openings. The wall <NUM> of the cover <NUM> defines a plurality of secondary ball openings <NUM> that are in line with the ball openings in the main wall <NUM> yet sized slightly smaller than a diameter of the balls <NUM>. As a result, the balls <NUM> are able to protrude beyond the wall <NUM> yet be held in placed between the wall <NUM> and the main wall <NUM>.

The main wall <NUM> has a plurality of counterbores <NUM> that further define the ball openings. The counterbores <NUM> are sized with a diameter slightly larger than each of the balls <NUM> so that the balls <NUM> can be seated in the ball openings. The counterbores <NUM> are also sized so that seals <NUM> such as o-rings can be placed in the counterbores <NUM> to seal about the balls <NUM> and against the main wall <NUM>. As shown, two seals <NUM> are located in each of the counterbores <NUM> (see also <FIG>). The seals <NUM> are held in place by virtue of the wall <NUM> being located over the seals <NUM>. The wall <NUM> engages one of each pair of seals <NUM> to further enhance the barrier.

The seals <NUM> are resilient so that the balls <NUM> are able to move slightly laterally in the ball openings, e.g., the balls <NUM> are not constrained from lateral movement in the ball openings. As a result, distances between the balls <NUM> are able to adjust, e.g., increase or decrease, so that the balls <NUM> seat properly into the receptacles <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, particularly when each of the second plurality of receptacles <NUM>, <NUM>, <NUM> have conical configurations, which are rigidly fixed in position relative to one another. Owing to the ability of the balls <NUM> to adjust laterally, the balls <NUM> are able to fit neatly into the conical receptacles, thereby enabling three points of contact with the balls <NUM>.

As described above, the balls <NUM> are arranged for receipt in the first and second plurality of receptacles <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> to kinematically couple the first and second mounting portions <NUM>, <NUM>. The balls <NUM> are located so that the barrier remains unbroken between the main wall <NUM> and the balls <NUM> to reduce the potential for migration of contaminants through the interface <NUM>. Thus, the drape <NUM> and interface <NUM> provide a continuous barrier to the migration of contaminants from the robotic arm R into the sterile field S.

In this embodiment, the balls <NUM> have polished, corrosion-resistant surfaces, so that under certain loads submicron repeatability in positioning the mounting portions <NUM>, <NUM> can be achieved. The balls <NUM> may be formed of ceramic, stainless steel, or other suitable materials. The balls <NUM> may be formed of silicon carbide or tungsten carbide. The balls <NUM> may be precision machined to very tight tolerances, for example less than <NUM>,08e-<NUM> cm (fifty millionths of an inch).

The interface <NUM> includes a plurality of electrical terminals embedded in the cover <NUM>, as shown in <FIG>. In this embodiment, the electrical terminals are pins <NUM> that may be insert molded into the cover <NUM> of the interface <NUM>. The pins <NUM> are located in a connector portion <NUM> of the cover <NUM>. The connector portion <NUM> partially passes through an aperture <NUM> in the latch bracket <NUM>. The connector portion <NUM> may be press fit into the aperture <NUM> to reduce the potential for contaminants to migrate through the interface <NUM>. A peripheral seal (not shown) may also be present to seal against the connector portion <NUM> and the main wall <NUM> in the aperture <NUM> to further reduce the potential for contaminants to migrate through the interface <NUM>. The pins <NUM> transfer electrical power/signals across the sterile barrier assembly <NUM>.

Referring to <FIG>, the first mounting portion <NUM> includes a first catch <NUM>. In this embodiment, the first catch <NUM> is a sliding catch plate. The first catch <NUM> defines a pair of spaced apertures <NUM> (<FIG>). The first catch <NUM> is slidably disposed in the first body <NUM>. The first body <NUM> includes a forward wall <NUM>. A cover plate <NUM> is mounted to the forward wall <NUM> to define a catch guide recess <NUM>. The first catch <NUM> slides in the catch guide recess <NUM>.

One or more compression springs <NUM> biases the first catch <NUM> upwardly so that an upper edge of the first catch <NUM> contacts a downwardly facing edge of the forward wall <NUM> defining the catch guide recess <NUM>. The compression springs <NUM> act between a lower edge of the first catch <NUM> and an opposing upwardly facing edge of the forward wall <NUM> defining the catch guide recess <NUM>.

The forward wall <NUM> also defines a latch aperture <NUM> through which the latches <NUM> are able to engage the first catch <NUM>. In the normal state, the apertures <NUM> are only partially aligned with the latch aperture <NUM>, as shown in <FIG>. Still, a large enough portion of the apertures <NUM> are exposed through the latch aperture <NUM> for the latches <NUM> to engage the first catch <NUM>.

Each of the latches <NUM> has a head <NUM> that tapers to a front surface sized to fit within the exposed portion of the apertures <NUM>. As the front surfaces of each head <NUM> moves into and through the exposed portion of the apertures <NUM>, a tapered surface of the head <NUM> cams the first catch <NUM> downwardly against the bias of the compression springs <NUM> until the head <NUM> moves entirely through the apertures <NUM>. Once the heads <NUM> have passed entirely through the apertures <NUM>, the first catch <NUM> slides upwardly into a latch recess <NUM> defined by each of the heads <NUM> under the bias of the compression springs <NUM>. This holds the latch bracket <NUM>, and by extension the entire sterile barrier assembly <NUM>, onto the first body <NUM>.

This latch/catch arrangement allows the interface <NUM> to engage the first body <NUM> without requiring any tilting therebetween. In other words, the interface <NUM> can be pressed into engagement with the first body <NUM> by solely translational or linear movement of the interface <NUM>. This further facilitates the engagement of the pins <NUM> into corresponding electrical connectors <NUM>, <NUM> on the first body <NUM> and second body <NUM>. It should be appreciated that the latches <NUM> and the first catch <NUM> could be reversed or that the latches <NUM> and the first catch <NUM> could be referred to as catches <NUM> and the first latch <NUM>.

An actuator <NUM> is used to release the latch bracket <NUM> from the first body. The actuator <NUM> is fixed to the first catch <NUM>. In this embodiment, the actuator <NUM> is U-shaped and can be actuated by pressing the actuator <NUM> downwardly to move the first catch <NUM> downwardly against the bias of the compression springs <NUM> so that the heads <NUM> of the latches <NUM> can be pulled back out through the apertures <NUM> and the latch aperture <NUM>.

Referring to <FIG>, with the interface <NUM> supported by the first body <NUM>, the second body <NUM> is ready to engage the interface <NUM>. A latch hook <NUM> is located to easily engage a second catch <NUM> fixed to the second body <NUM> (or could be referred to as the catch hook <NUM> and the second latch <NUM>). The latch hook <NUM> is pivotally supported by the latch bracket <NUM>. A torsion spring (not numbered in <FIG>) biases the latch hook <NUM> into engagement with the second catch <NUM>.

The second catch <NUM> is a D-shaped rod fixed to the second body <NUM> and shaped to engage the latch hook <NUM>. The second body <NUM> is simply pressed onto the interface <NUM> until the latch hook <NUM> engages the second catch <NUM>. More specifically, as the second body <NUM> is pressed onto the interface <NUM>, the second catch <NUM> presses against a tapered face of of the latch hook <NUM> thereby urging the latch hook <NUM> to pivot upwardly against the bias of the torsion spring until a recess in the latch hook <NUM> aligns with the second catch <NUM> at which time the torsion spring urges the latch hook <NUM> over the second catch <NUM>, as shown in <FIG>. Now the mounting system <NUM> is ready to be preloaded and prepared for use. In this state, the mounting system <NUM> acts as a support mechanism to support the end effector EE on the robotic arm R prior to preloading.

Referring to <FIG>, a preloading mechanism <NUM> clamps the mounting portions <NUM>, <NUM> together in position once they are brought together in approximate final orientation. A preloading element is located in the interface <NUM>. In this embodiment, the preloading element is an elongated load member <NUM>. The load member <NUM> is movably supported in the interface <NUM>. The load member <NUM> has first and second ends. The load member <NUM> may be formed of stainless steel, Kevlar composite, or other suitably rigid materials. The load member <NUM> defines an aperture <NUM> near one end and the latch hook <NUM> adjacent the opposite end.

A preload force is applied to the load member <NUM>. The preload force is sized to exceed anticipated loading through the kinematic coupling so that the kinematic coupling and associated properties are maintained.

The load member <NUM> is movably supported by the latch bracket <NUM>. In particular, the load member <NUM> is able to move from an unloaded position to a loaded position relative to the latch bracket <NUM>. In the unloaded position, the latch hook <NUM> is located to engage the second catch <NUM>. In the loaded position, the load member <NUM> is urged toward the latch bracket <NUM> to load the mounting system <NUM>.

The preloading mechanism <NUM> further includes a tensioner <NUM> (<FIG>) and a spring cup <NUM> coupled to the tensioner <NUM>. The tensioner <NUM> includes a cam shaft <NUM> that fits inside a pair of concentric inner and outer tubes <NUM>, <NUM>. The tubes <NUM>, <NUM> are hollow and cylindrical. The tubes <NUM>, <NUM> are fixed from translation relative to the spring cup <NUM> so that as the tubes <NUM>, <NUM> move in translation, so does the spring cup <NUM>.

The spring cup <NUM> defines a first cup opening <NUM> (<FIG>) that is sized to receive the outer tube <NUM>. Opposite the first cup opening <NUM>, the spring cup <NUM> defines a spring cup counterbore <NUM> (<FIG>) sized to receive the outer tube <NUM>. The outer tube <NUM> may be press fit into the first cup opening <NUM> and the spring cup counterbore <NUM> so that the outer tube <NUM> is unable to rotate relative to the spring cup <NUM>, or the outer tube <NUM> may be allowed to rotate therein but be fixed from moving in translation relative to the spring cup <NUM>. The outer tube <NUM> passes through the aperture <NUM> of the load member <NUM>.

The latch hook <NUM> protrudes beyond a central opening in the spring cup <NUM>. The latch hook <NUM> also protrudes beyond a central opening in a top of the outer wall <NUM> to reach the second catch <NUM> of the second body <NUM>. The spring cup <NUM> is sized so that the spring cup <NUM> is unable to pass through the central opening in the top of the outer wall <NUM>. The spring cup <NUM> and outer wall <NUM> have chamfered surfaces configured to clear one another in the unloaded state when the latch hook <NUM> is released as described further below.

The cam shaft <NUM> is supported for rotation by the inner wall <NUM> of the latch bracket <NUM>. The inner wall <NUM> defines a pair of throughbores <NUM> (<FIG>). A pair of bushings <NUM> are press fit into the throughbores <NUM> and rotatably support outer cylindrical sections <NUM> of the cam shaft <NUM>. As a result, the cam shaft <NUM> is able to rotate relative to the latch bracket <NUM> between tensioned and untensioned positions. The cam shaft <NUM> includes a pair of cam sections <NUM> separated by a middle cylindrical section <NUM>. The cam sections <NUM> have an outer diameter slightly smaller than an inner diameter of the inner tube <NUM>. The cylindrical sections <NUM> of the cam shaft <NUM> have a smaller diameter than the cam sections <NUM> thereby creating a camming action as the cam shaft <NUM> is rotated.

The inner and outer tubes <NUM>, <NUM> each have a length less than a length across opposing sections of the inner wall <NUM> between the throughbores <NUM>. As a result, the inner and outer tubes <NUM>, <NUM> can move in translation relative to the inner wall <NUM>. As the cam shaft <NUM> is rotated, the inner and outer tubes <NUM>, <NUM> move under the cam action of the cam shaft <NUM> toward and away from the main wall <NUM>. This movement provides the preloading needed to load the load member <NUM> once the latch hook <NUM> has engaged the second catch <NUM>.

The tensioner <NUM> also includes a lever <NUM> rotatably fixed to the cam shaft <NUM>. The lever <NUM> includes a boss <NUM> having a D-shaped bore to receive the D-shaped portion of the cam shaft <NUM> so that the cam shaft <NUM> rotates as the lever <NUM> rotates. A fastener (not numbered) engages a threaded end of the cam shaft <NUM> to secure the lever <NUM> to the cam shaft <NUM>. The cam shaft <NUM> is rotated at least ninety degrees to move between the unloaded and loaded positions. Of course, other positions therebetween may place tension on the load member <NUM> and could be suitable for applying the desired preload force.

The lever <NUM> may be locked when the cam shaft <NUM> is placed in the desired position, e.g., the loaded position. In the loaded position, the preload tensile force is applied to the load member <NUM>. By locking the lever <NUM> after applying the preload force, the preload force is continually applied during use of the robotic arm R and end effector EE to maintain the kinematic coupling. The preloading mechanism <NUM> transfers the preload force across the sterile barrier assembly <NUM> without piercing the barrier.

The tensioner <NUM> applies the preload force to the load member <NUM> through a conical disc spring <NUM>, such as a Belleville spring. The disc spring <NUM> applies a force equal to the preload force to the load member <NUM>. The disc spring <NUM> acts between the spring cup <NUM> and a shoulder <NUM> of the load member <NUM>. In particular, as the lever <NUM> is rotated, the cam shaft <NUM> rotates and the cam sections <NUM> move the inner and outer tubes <NUM>, <NUM>, and by extension the spring cup <NUM>, away from the latch hook <NUM> (now engaging the second catch <NUM>). The inner and outer tubes <NUM>, <NUM> are also able to move relative to the load member <NUM> by virtue of moving in the aperture <NUM>, which is elongated to accommodate for such movement. The movement of the spring cup <NUM> relative to the load member <NUM> compresses the disc spring <NUM> and applies the preload force onto the load member <NUM> via the shoulder <NUM>.

Since the balls <NUM> are aligned with the first and second plurality of receptacles <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, once the preload force is applied, the balls <NUM> become seated in the receptacles <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. Once seated, positions of the balls <NUM> are fixed and the positions of the first and second plurality of receptacles <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> are fixed relative to one another. As a result, the first and second mounting portions <NUM>, <NUM> are kinematically coupled together without piercing the sterile barrier assembly <NUM>.

Release of the latch hook <NUM> is facilitated by urging the latch hook <NUM> upwardly away from the second catch <NUM>. This is accomplished by rotating the lever <NUM> further counterclockwise when in the unloaded position. This movement causes the cam shaft <NUM> to interact with a second cup opening <NUM> defined in the spring cup <NUM> to pivot the spring cup <NUM> and the latch hook <NUM> to release the latch hook <NUM> from the second catch <NUM>.

The second cup opening <NUM> is smaller than the outer tube <NUM>, yet large enough to accommodate an eccentric portion <NUM> of the cam shaft <NUM>. The second cup opening <NUM> has an eccentric shape as shown in <FIG> and is dimensioned so that in the unloaded position the eccentric portion <NUM> rests in the location indicated in solid lines in <FIG>. From this position, when the eccentric portion <NUM> is further rotated counterclockwise via lever <NUM>, the eccentric portion <NUM> engages the spring cup <NUM> in a manner that causes pivoting of the spring cup <NUM>. More specifically, since the eccentric portion <NUM> is constrained from further rotating counterclockwise given the dimensions of the second cup opening <NUM> (as viewed in <FIG>), further counterclockwise motion of the lever <NUM> pivots the spring cup <NUM> relative to the outer wall <NUM>, and thereby moves the latch hook <NUM> upwardly away from the second catch <NUM>. In the loaded position, the eccentric portion <NUM> rests in the location indicated by dashed lines in <FIG>.

<FIG> shows electrical power and/or other signal connections that can be made through the sterile barrier assembly <NUM>. These connections employ the pins <NUM> embedded in the interface <NUM>. These pins <NUM> electrically interconnect electrical connectors <NUM>, <NUM> attached to the first and second mounting portions <NUM>, <NUM>.

In this embodiment, the first mounting portion <NUM> includes the first electrical connector <NUM>. The first electrical connector <NUM> is able to float relative to the first body <NUM>. The second mounting portion <NUM> includes the second electrical connector <NUM>. The second electrical connector <NUM> also floats relative to the second body <NUM>. When the first and second mounting portions <NUM>, <NUM> are kinematically coupled together and preloaded, the electrical connectors <NUM>, <NUM> receive the pins <NUM> so that power or other electrical signals can flow through the pins <NUM>. Thus, power, communication signals, or other signals can be passed from the robotic arm R to the end effector EE and vice versa.

<FIG> shows the steps of attaching the sterile barrier assembly <NUM> first to the first mounting portion <NUM> (which is fixed to the robotic arm R), then attaching the second mounting portion <NUM> (shown in phantom integrated into the end effector EE) to the sterile barrier assembly <NUM>, and then pivoting the lever <NUM> downwardly to load the mounting system <NUM> and apply the preload force necessary to maintain positioning between the first mounting portion <NUM> and the second mounting portion <NUM>.

Referring to <FIG>, another alternative mounting system is shown for kinematically coupling the first and second surgical components (e.g., robotic arm R and end effector EE) using a sterile barrier assembly <NUM>.

Referring to <FIG>, a plurality of kinematic couplers, similar to those of prior embodiments, are used to kinematically couple the end effector EE to the robot arm R. In this embodiment, the kinematic couplers are spherical balls <NUM>. The balls <NUM> are seated in first and second pluralities of receptacles <NUM>, <NUM> (one pair shown in <FIG>). The receptacles <NUM>, <NUM> are sized and shaped to receive the balls <NUM>, as previously described. The first plurality of receptacles <NUM> are fixed to a first mounting portion <NUM> of the robot arm R and the second plurality of receptacles <NUM> are fixed to a second mounting portion <NUM> of the end effector EE.

The first plurality of receptacles <NUM> includes three receptacles (only one shown in <FIG>). Each of the first plurality of receptacles <NUM> has a pair of contact surfaces <NUM> provided by a V-shaped groove or gothic arch (also referred to as V-grooved receptacles). The second plurality of receptacles <NUM> includes three receptacles (only one shown in <FIG>). Each of the second plurality of receptacles has a contact surface <NUM> with a conical configuration (i.e., cone receptacles). Three balls <NUM> are captured between corresponding, aligned pairs of the receptacles <NUM>, <NUM>.

When the mounting portions <NUM>, <NUM> of the robot arm R and the end effector EE are brought together in approximate final orientation with the sterile barrier assembly <NUM> positioned therebetween, the balls <NUM> of the sterile barrier assembly <NUM> self-seat into the receptacles <NUM>, <NUM> so that exactly six degrees of freedom are constrained, as described in the prior embodiments.

The sterile barrier assembly <NUM> includes a protective covering <NUM>. The protective covering <NUM> includes an interface <NUM> and a drape <NUM> attached to the interface <NUM>. The drape <NUM> has an interior surface and an exterior surface. The interior surface is placed adjacent to the robotic arm R during surgery. The drape <NUM> is formed of at least one of polyethylene, polyurethane, polycarbonate, or other suitable materials. The drape <NUM> may be directly attached to the interface <NUM> by ultrasonic welding, tape, adhesive, or the like.

In the embodiment shown, the drape <NUM> comprises a ring <NUM> that engages the interface <NUM>. The ring <NUM> defines an opening. In the embodiment shown, the ring <NUM> is a snap-ring. A flaccid portion of the drape <NUM> is attached to the snap-ring <NUM> to surround the opening by ultrasonic welding, tape, adhesive, or the like. When draping the robot arm R, the snap-ring <NUM> (with flaccid portion attached thereto) is first snap-fit to the interface <NUM>, prior to the interface <NUM> being mounted to the first mounting portion <NUM> of the robot arm R. The interface <NUM> fits into the opening in the snap-ring <NUM>. Once the snap-ring <NUM> is snap-fit to the interface <NUM>, the interface <NUM> is mounted to the first mounting portion <NUM> of the robot arm R. The drape <NUM> is attached to the interface <NUM> so that no perforations are present or are sealed, i.e., the drape <NUM> forms a continuous barrier with the interface <NUM> through the snap-ring <NUM> or other similar attachment mechanism. The drape <NUM> is absent in several Figures to better illustrate other components.

Referring to <FIG> and <FIG>, in the embodiment shown, the interface <NUM> comprises a back plate assembly <NUM> that is secured to a cover <NUM>. The back plate assembly <NUM> is formed of two separate components - a back ring plate <NUM> that is mounted by fasteners to the cover <NUM> and a back cover plate <NUM> that is captured between the back ring plate <NUM> and the cover <NUM>.

Referring to <FIG> and <FIG>, the interface <NUM> further includes a latch assembly <NUM>. The latch assembly <NUM> includes a latch bracket <NUM> having spaced apart inner walls <NUM>. A pair of latches <NUM> are held within a travel passage defined in the latch bracket <NUM> by the spaced apart inner walls <NUM>.

The back cover plate <NUM> is fixed to the latch bracket <NUM> (e.g., via fasteners) and spaced from the latch bracket <NUM> to further define the travel passage for the latches <NUM>. Each of the latches <NUM> are captured in the travel passage. A pair of biasing members B, such as springs, bias the latches <NUM> toward each other. The biasing members B act between the inner walls <NUM> and the latches <NUM>. In this embodiment, the latches <NUM> are in the form of latch plates with arcuate recesses (see <FIG>) to engage a first catch <NUM> of the first mounting portion <NUM> as described below.

The cover <NUM> has a peripheral lip <NUM>. The cover <NUM> may be formed of injection molded plastic or metal. The peripheral lip <NUM> is secured around the back plate assembly <NUM>. The cover <NUM> includes an outer wall <NUM> and a wall <NUM>. The wall <NUM> extends from a base of the outer wall <NUM> to the peripheral lip <NUM>. Seals (not shown) may be located between the cover <NUM> and the back plate assembly <NUM> to further enhance the barrier.

The interface <NUM> includes the balls <NUM> integrated therein. In this embodiment, the balls <NUM> are located in ball openings defined in the cover <NUM> and the back ring plate <NUM>. The ball openings are sized so that a portion of each of the balls <NUM> protrudes out from the back ring plate <NUM> and the wall <NUM> of the cover <NUM> to engage the receptacles <NUM>, <NUM>. Seals that are X-shaped in cross-section hold the balls <NUM> in the ball openings and provide a sterile barrier around the balls <NUM>, while still allowing the balls <NUM> lateral movement within the ball openings.

As described above, the balls <NUM> are arranged for receipt in the receptacles <NUM>, <NUM> to kinematically couple the mounting portions <NUM>, <NUM>. The balls <NUM> are located so that the barrier remains unbroken between the back ring plate <NUM> and the balls <NUM> to reduce the potential for migration of contaminants through the interface <NUM>. Thus, the drape <NUM> and interface <NUM> provide a continuous barrier to the migration of contaminants from the robotic arm R into the sterile field S.

The first mounting portion <NUM> includes the first catch <NUM>. In this embodiment, the first catch <NUM> is a catch post having a head <NUM> and a groove <NUM> proximal to the head <NUM>. The latches <NUM> engage the first catch <NUM> in the groove <NUM>. The back cover plate <NUM> defines a latch aperture <NUM> through which the head <NUM> is able to engage the latches <NUM>. The head <NUM> is tapered to engage the latches <NUM>. More specifically, the head <NUM> is tapered to spread apart the latches <NUM> from their normal positions (see <FIG>). As the head <NUM> moves between the latches <NUM>, a tapered surface of the head <NUM> spreads the latches <NUM> apart against the bias of the biasing members B until the head <NUM> moves entirely past the latches <NUM>. Once the head <NUM> is past the latches <NUM>, the latches <NUM> slide into the groove <NUM> to hold the sterile barrier assembly <NUM> onto the first mounting portion <NUM>. Progressive engagement of the first catch <NUM> by the first pair of latches <NUM> is shown in <FIG> and <FIG>.

This latch/catch arrangement allows the interface <NUM> to engage the first mounting portion <NUM> without requiring any tilting therebetween. In other words, the interface <NUM> can be pressed into engagement with the first mounting portion <NUM> by solely longitudinal or linear movement of the interface <NUM>.

Referring to <FIG> and <FIG>, with the interface <NUM> supported by the first mounting portion <NUM>, the end effector EE is now able to engage the interface <NUM>. A second catch <NUM>, similarly shaped to the first catch <NUM> is located to easily engage a second pair of latches <NUM> fixed to the second mounting portion <NUM>. Operation and function of the second catch <NUM> and the second pair of latches <NUM> is similar to the first catch <NUM> and the first pair of latches <NUM> and will not be described in detail, but is progressively shown in <FIG> and <FIG>. The second mounting portion <NUM>, which is attached to the end effector EE, is simply pressed onto the interface <NUM> until the second catch <NUM> engages the second pair of latches <NUM>, as shown in <FIG>. Now the mounting system is ready to be preloaded and prepared for use. In this state, the mounting system acts as a support mechanism to support the end effector EE on the robotic arm R prior to preloading.

Referring to <FIG> and <FIG>, a preloading mechanism <NUM> clamps the mounting portions <NUM>, <NUM> together in position once they are brought together in approximate final orientation. A preloading element is located in the interface <NUM>. In this embodiment, the preloading element is an elongated load member <NUM>. The load member <NUM> is movably supported in the interface <NUM>. The load member <NUM> has first and second ends. The load member <NUM> may be formed of stainless steel, Kevlar composite, or other suitably rigid materials. The load member <NUM> comprises a flange <NUM> near one end and the second catch <NUM> adjacent the opposite end.

The load member <NUM> is movably captured between the cover <NUM> and the back plate assembly <NUM>. In particular, the load member <NUM> is able to move from an unloaded position to a loaded position relative to the cover <NUM> and the back plate assembly <NUM>. In the unloaded position, the second catch <NUM> is able to engage the second pair of latches <NUM>. In the loaded position, the load member <NUM> is urged toward the back plate assembly <NUM> to load the mounting system.

Guide blocks <NUM> interconnect a cover plate <NUM> and the latch bracket <NUM>. More specifically, the guide blocks <NUM> define bores through which fasteners pass to engage the latch bracket <NUM>. The guide blocks <NUM> are arranged to space the cover plate <NUM> from the latch bracket <NUM>. As a result, an internal space is provided in the interface <NUM> in which the load member <NUM> can be moved during preloading.

The preloading mechanism <NUM> further includes a spring plate <NUM> and a conical disc spring <NUM>, such as a Belleville spring, disposed between the flange <NUM> of the load member <NUM> and the spring plate <NUM>. The spring plate <NUM> defines a first opening <NUM> (see <FIG>) that is sized to receive the load member <NUM>. The disc spring <NUM> defines a second opening <NUM> that is also sized to receive the load member <NUM>. A snap-ring secures the spring plate <NUM> and disc spring <NUM> to the load member <NUM>.

The preloading mechanism <NUM> also includes a tensioner configured to, when actuated, urge the load member <NUM> toward the back plate assembly <NUM> to load the mounting system. The tensioner includes a cam shaft <NUM> supported for rotation relative to the cover <NUM> (see <FIG>). The tensioner also includes a pair of tensioning members <NUM> (also referred to as lifters). The tensioning members <NUM> are located between the cover plate <NUM> and the spring plate <NUM>. The cover plate <NUM> is fastened to the latch bracket <NUM> via fasteners.

The cam shaft <NUM> is supported for rotation by the guide blocks <NUM>. As a result, the cam shaft <NUM> is able to rotate between tensioned and untensioned positions. The cam shaft <NUM> includes a pair of cam sections <NUM> separated by a middle cylindrical section <NUM>. The cylindrical section <NUM> of the cam shaft <NUM> has a smaller diameter than the cam sections <NUM>. The cam sections <NUM> create a camming action as the cam shaft <NUM> is rotated.

As shown in <FIG>, the tensioning members <NUM> (two in the embodiment shown) have first ends engaged by the cam shaft <NUM> and second ends that engage the spring plate <NUM>. The second ends have rounded engagement sections <NUM> that sit in grooves <NUM> in the spring plate <NUM>. As the cam shaft <NUM> is rotated about a pivot axis P1, the tensioning members <NUM> pivot about a pivot axis P2 while abutting the cover plate <NUM>. This action pivots their second ends into the spring plate <NUM> to urge the spring plate <NUM> away from the cover plate <NUM>. Owing to the rigid connection of the cover plate <NUM> to the latch bracket <NUM> and the latch bracket <NUM> to the back cover plate <NUM>, the load member <NUM> moves toward the first catch <NUM> (which draws the second catch <NUM> toward the first catch <NUM>), thereby providing the preloading needed to suitably secure the end effector EE to the robot arm R.

As shown in <FIG>, the tensioner also includes a lever <NUM> rotatably fixed to the cam shaft <NUM>. The lever <NUM> may be rotatably fixed to the cam shaft <NUM> through various types of engagements, e.g., a D-shaped bore to receive a D-shaped portion of the cam shaft <NUM>, a coupler with geometric features so that the cam shaft <NUM> rotates as the lever <NUM> is rotated, etc. In the embodiment shown, a fastener (not numbered) secures the lever <NUM> to the cam shaft <NUM> via a coupler. The cam shaft <NUM> is rotated at least ninety degrees to move between the unloaded and loaded positions. Of course, other positions therebetween may place tension on the load member <NUM> and could be suitable for applying the desired preload force.

The lever <NUM> may be locked when the cam shaft <NUM> is placed in the desired position, e.g., the tensioned position. In the tensioned position, the preload tensile force is applied to the load member <NUM>. By locking the lever <NUM> after applying the preload force, the preload force is continually applied during use of the robotic arm R and end effector EE to maintain the kinematic coupling. The preloading mechanism <NUM> transfers the preload force across the sterile barrier assembly <NUM> without piercing the barrier.

The tensioner applies the preload force to the load member <NUM> through the disc spring <NUM>. The disc spring <NUM> applies a force equal to the preload force to the load member <NUM>. The disc spring <NUM> acts between the spring plate <NUM> and the flange <NUM> of the load member <NUM>. In particular, as the lever <NUM> is rotated, the cam shaft <NUM> rotates and the cam sections <NUM> pivot the tensioning members <NUM> about the pivot axis P2, and by extension, the spring plate <NUM> moves longitudinally away from the second catch <NUM> (which is engaging the second pair of latches <NUM>). The movement of the spring plate <NUM> compresses the disc spring <NUM> and applies the preload force onto the load member <NUM> via the flange <NUM>.

Since the balls <NUM> are already generally aligned with the receptacles <NUM>, <NUM> before preloading, once the preload force is applied, the balls <NUM> become seated in the receptacles <NUM>, <NUM>. Once seated, positions of the balls <NUM> are fixed and the positions of the receptacles <NUM>, <NUM> are fixed relative to one another. As a result, the mounting portions <NUM>, <NUM> are kinematically coupled together without piercing the sterile barrier assembly <NUM>.

Actuators, such as the push-button actuator <NUM> shown in <FIG>, are used to manually separate the latches <NUM>, <NUM> and release the catches <NUM>, <NUM> so that the end effector EE can be removed from the interface <NUM> and the interface <NUM> can be removed from the robot arm R. Only the actuator <NUM> used to separate the first pair of latches <NUM> and release the first catch <NUM> will be shown and described in detail.

In the embodiment shown, the actuator <NUM> has a push button <NUM> fixed to a release frame <NUM>. The release frame <NUM> is arranged with angled engagement surfaces <NUM> that engage pins <NUM> fixed to each of the first pair of latches <NUM>. The pins <NUM> extend away from the latches <NUM> into openings <NUM> in the release frame <NUM>. The openings <NUM> are partially defined by the angled engagement surfaces <NUM>. The pins <NUM> extend on either side of the latch bracket <NUM> (see <FIG>) so that the latches <NUM> are guided to move along the latch bracket <NUM> via the pins <NUM>.

In a normal, unactuated state, the pins <NUM>, by virtue of the latches <NUM> being biased toward one another by the biasing members B, are seated and constrained at one end of the openings <NUM>. The actuator <NUM> can be actuated by pressing the push button <NUM>, which moves the release frame <NUM> laterally across the latches <NUM>, as shown by the arrow A1. The release frame <NUM> is constrained to this lateral motion by being captured in a slide pocket in the latch bracket <NUM>. Owing to this lateral motion of the release frame <NUM> and the latches <NUM> being constrained from similar lateral movement by the pins <NUM>, the angled surfaces <NUM> urge the pins <NUM> of each of the latches <NUM> away from each other, thereby separating the latches <NUM> in the direction shown by arrows A2 against the bias of the biasing members B. As a result, the latches <NUM> are disengaged from the first catch <NUM> (not shown in <FIG>) and the interface <NUM> can be removed from the first mounting portion <NUM>.

<FIG> shows electrical power and other signal connections that can be made through the sterile barrier assembly <NUM>. In this embodiment, the interface <NUM> includes a plurality of electrical terminals embedded in a carrier <NUM> disposed centrally in the cover <NUM>. In this embodiment, the electrical terminals are pins <NUM> that may be insert molded into the carrier <NUM> of the interface <NUM>. The pins <NUM> transfer electrical power/signals across the sterile barrier assembly <NUM>. These pins <NUM> electrically interconnect electrical connectors <NUM>, <NUM> attached to the mounting portions <NUM>, <NUM>.

In this embodiment, the first mounting portion <NUM> includes the first electrical connector <NUM>. The second mounting portion <NUM> includes the second electrical connector <NUM>. When the mounting portions <NUM>, <NUM> are coupled together and preloaded, the electrical connectors <NUM>, <NUM> receive the pins <NUM> so that power and other electrical signals can flow through the pins <NUM>. Thus, power, communication signals, or other signals can be passed from the robotic arm R to the end effector EE and vice versa. The electrical connectors <NUM>, <NUM> can be keyed to the carrier <NUM> via a key/channel type interface or can be properly oriented by any suitable feature.

In the embodiment shown, the carrier <NUM> comprises a flange <NUM> (see <FIG>) and a cylindrical body <NUM> extending from the flange <NUM> to support the pins <NUM>. The cylindrical body <NUM> is sized to fit within a cylindrical passage through the load member <NUM>. A wave spring <NUM> is located between the flange <NUM> of the carrier <NUM> and the flange <NUM> of the load member <NUM>. The wave spring <NUM> helps to maintain a position of the carrier <NUM> with respect to the electrical connectors <NUM>, <NUM>, i.e., by preventing movement of the carrier <NUM> when the load member <NUM> moves to the unloaded position, which might otherwise occur due to frictional engagement between the cylindrical body <NUM> in the cylindrical passage of the load member <NUM>. The wave spring <NUM> also assists in returning the load member <NUM> to its unloaded position to engage the end effector EE. The wave spring <NUM> is also used to keep the tensioning members <NUM> in grooves in the cover plate <NUM> and in the grooves <NUM> in the spring plate <NUM>.

Referring to <FIG>, the back ring plate <NUM> of the interface <NUM> further includes gross alignment features for aligning the interface <NUM> with the first mounting portion <NUM>. In particular, the first mounting portion <NUM> defines corresponding mating features for receiving the alignment features. In the embodiment shown, the alignment features comprise posts <NUM>, <NUM> extending rearwardly from a rear surface of the back ring plate <NUM> to engage openings <NUM>, <NUM> in the first mounting portion <NUM>. The posts <NUM>, <NUM> include a first pair of posts <NUM> and a second pair of posts <NUM> arranged on the back ring plate <NUM> opposite the first pair of posts <NUM>. The first pair of posts <NUM> are aligned in a plane, while the second pair of posts <NUM> are angled relative to one another, e.g., they are misaligned. The second pair of posts <NUM> are also wider than the first pair of posts <NUM>.

The openings <NUM>, <NUM> comprise a first pair of openings <NUM> sized and shaped to receive the first pair of posts <NUM> and a second pair of openings <NUM> sized and shaped to receive the second pair of posts <NUM>. The openings <NUM>, <NUM> are sized and spaced to receive the respective posts <NUM>, <NUM> with a small tolerance, e.g., to facilitate gross positioning. Still, the second pair of posts <NUM> are sized so that they are unable to fit in the first pair of openings <NUM> and the first pair of posts <NUM> are aligned so that they are unable to fit in the second pair of openings <NUM>. Owing to the spacing/arrangement of the posts <NUM>, <NUM> and the openings <NUM>, <NUM>, the interface <NUM> is only able to be grossly fitted onto the first mounting portion <NUM> in one orientation. The gross positioning also helps to align the electrical connections described above prior to fully engaging the first catch <NUM> with the latches <NUM>.

When the balls <NUM>, <NUM>, <NUM> are made of an electrically insulating material such as ceramic, the sterile barrier assembly <NUM>, <NUM>, <NUM> can be used as the electrical isolation needed to comply with electrical safety requirements.

The balls <NUM>, <NUM>, <NUM> may provide three electrical contacts or terminals if they are made of a conductive material. In such a case, the sterile barrier assembly <NUM>, <NUM>, <NUM> could still be used as the electrical isolation if the interfacing feature of the kinematic coupling is made out of electrically insulating material.

One or more of the balls <NUM>, <NUM>, <NUM> may have optically transparent portions defined therethrough for transmitting data. The optically transparent portions may include throughbores filled with transparent plastic material or other material to maintain the barrier.

The kinematic couplers may have spherical and/or cylindrical segments in other embodiments.

The first mounting portion <NUM>, <NUM>, <NUM> may be a separate part that is rigidly connected to linkage L1 of the robotic arm R. The second mounting portion <NUM>, <NUM>, <NUM> may be a separate part that is rigidly connected to a handpiece H of the end effector EE. In other embodiments, the first mounting portion <NUM>, <NUM>, <NUM> may be integrated into the one or more linkages of the robotic arm R and the second mounting portion <NUM>, <NUM>, <NUM> may be integrated into the handpiece of the end effector EE. The mounting portions <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may be formed of hardened steel, stainless steel or other rigid materials.

The robotic arm R may move the end effector EE in one or more degrees of freedom, including five or six degrees of freedom. The end effector EE may include a surgical tool for milling tissue such as a milling bur for milling bone to receive an implant.

Examples of a robotic arm and end effector that can be outfitted with the first and second mounting portions <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> are described in <CIT>, entitled, "Surgical Manipulator Capable of Controlling a Surgical Instrument in Multiple Modes".

The first plurality of receptacles may include three V-grooved receptacles. The three balls <NUM>, <NUM>, <NUM> would then self-center into three V-shaped grooves of the three V-grooved receptacles so that each ball <NUM>, <NUM>, <NUM> is contacting two surfaces of the V-shaped grooves at two contact points. As a result, the balls <NUM>, <NUM>, <NUM> make contact with the three V-grooved receptacles at a total of six contact points to constrain six degrees of freedom, i.e., each V-shaped groove constrains two degrees of freedom, thereby determinately orienting all six degrees of freedom between the first and second mounting portions. The first and second mounting portions are then clamped in this position with the preloading mechanism as previously described.

The first plurality of receptacles and the second plurality of receptacles may each include three V-grooved or gothic arch shaped receptacles so that exactly six contact points are made between contact surfaces of the first plurality of receptacles and the kinematic couplers and between contact surfaces of the second plurality of receptacles and the kinematic couplers.

The cone receptacles may be simplified by being replaced with three blocks having planar surfaces circumferentially equally spaced from one another and arranged at an angle approximating the cone angle. In this embodiment, the ball <NUM>, <NUM>, <NUM> seats within the three planar surfaces just like being seated in the cone, but contact is made at three contact points with the three planar surfaces.

One or more of the first plurality of receptacles and/or the second plurality of receptacles may comprise magnets to magnetically engage the balls in the receptacles. For instance, the first plurality of receptacles may comprise magnets to hold the balls to the first mounting portion until the second mounting portion is clamped to the first mounting portion. Similarly, the first mounting portion, having the contact surfaces of the receptacles integrated therein for kinematic coupling, could comprise magnets to hold the balls against the contact surfaces in the first mounting portion until the second mounting portion engages the first mounting portion.

The sterile barrier assembly <NUM>, <NUM>, <NUM> may be disposable. In other embodiments, the interface <NUM>, <NUM>, <NUM> may comprise a separate field sterilizable assembly and can be re-usable. In this version, only the drape <NUM>, <NUM>, <NUM> is disposable. In that case, there could be an adhesive tape, elastic seal, snap-ring, or mechanical clamping area of the drape <NUM>, <NUM>, <NUM> to seal to the interface <NUM>, <NUM>, <NUM> or features could be designed on the interface <NUM>, <NUM>, <NUM> to seal/clamp onto the drape <NUM>, <NUM>, <NUM>. Forming the balls <NUM>, <NUM>, <NUM> out of hard ceramic such as silicon carbide may minimize wear issues associated with reusing the balls <NUM>, <NUM>, <NUM>.

The protective covering <NUM>, <NUM>, <NUM> may include the drape <NUM>, <NUM>, <NUM> without the interface <NUM>, <NUM>, <NUM> in which case the balls <NUM>, <NUM>, <NUM> would be placed in openings in the drape <NUM>, <NUM>, <NUM> with the drape <NUM>, <NUM>, <NUM> being sealed to the balls <NUM>, <NUM>, <NUM>. In other words, the balls <NUM>, <NUM>, <NUM> would be integrated into the drape <NUM>, <NUM>, <NUM> directly. In this instance, the robotic arm R could be configured to position the first plurality of receptacles <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> so that they lie in a generally horizontal plane so that the balls <NUM>, <NUM>, <NUM> can be placed in the first plurality of receptacles <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and held there by gravity until installation of the sterile barrier assembly is complete.

Additional elastic straps or bungee cords may be attached to the interface and configured to releasably engage posts or other features on the first mounting portion to further initially support the sterile barrier assembly when initially attaching the sterile barrier assembly to the first mounting portion, e.g., after inserting the load bar <NUM> into the load bar slot <NUM> of the receiver <NUM>.

Claim 1:
A sterile barrier assembly (<NUM>, <NUM>, <NUM>) for establishing a barrier between first (R) and second (EE) surgical components, the sterile barrier assembly (<NUM>, <NUM>, <NUM>) comprising:
a protective covering (<NUM>, <NUM>, <NUM>) including:
an interface (<NUM>, <NUM>, <NUM>), including a plurality of kinematic couplers (<NUM>, <NUM>, <NUM>) integrated therein to provide a kinematic coupling between the first (R) and second (EE) surgical components through the protective covering (<NUM>, <NUM>, <NUM>); and
a drape (<NUM>, <NUM>, <NUM>) attached to the interface (<NUM>, <NUM>, <NUM>);
wherein the plurality of kinematic couplers (<NUM>, <NUM>, <NUM>) are further defined as a plurality of balls (<NUM>, <NUM>, <NUM>), and
wherein the interface (<NUM>, <NUM>, <NUM>) includes a load element (<NUM>, <NUM>, <NUM>) adapted to receive a preload force for preloading the kinematic coupling between the surgical components (R, EE).