Patent Description:
Devices such as that taught by <CIT>, apply vacuum-based massage therapy to a person's body, without having direct contact between the suction source and the skin. This is because direct contact could be dangerous and can cause pain and irritation. <CIT> proposes solving this problem by placing a membrane between the vacuum pump and the skin. This solution is not without problems that the present invention seeks to overcome by utilizing a different construction.

The present invention relates to head units for use with external devices based on an actuator using linear movement. Each of the head units includes at least one portion formed of a flexible material, which portion engages the subject's body.

In accordance with an embodiment of the present invention there is provided a head unit as set forth in claim <NUM> of the appended claims.

In some embodiments, a first height of the first protrusion is different from a second height of the second protrusion, and the graded manner of engagement and application of force is at least partially a result of the different first and second heights.

In some embodiments, the membrane is an equidistant membrane such that a first height of the first protrusion is equal to a second height of the second protrusion, and the graded manner of engagement and application of force is at least partially a result of the external surface being a graded external surface.

In some embodiments, the membrane is an equidistant membrane such that a first height of the first protrusion is equal to a second height of the second protrusion, and the graded manner of engagement and application of force is at least partially a result of angled application of force.

In some embodiments, the first protrusion is a central protrusion centered adjacent the main longitudinal axis, and the second protrusion is circumferential about the first protrusion.

In some embodiments, the first protrusion is a first circumferential protrusion disposed adjacent the main longitudinal axis, and the second protrusion is circumferential about the first circumferential protrusion. In some such embodiments, the first circumferential protrusion forms a complete circumference and has a fixed height along its entire circumference. In some other such embodiments, the first circumferential protrusion forms an incomplete circumference and has at least one segment having the first height and at least another segment having a third height, lower than the first height.

In some embodiments, the second circumferential protrusion forms a complete circumference and has a fixed height along its entire circumference. In some other embodiments, the second circumferential protrusion forms an incomplete circumference and has at least one segment having the second height and at least one other segment having a fourth height, lower than the second height.

In some embodiments, the membrane is formed of a viscoelastic material. In other embodiments, the membrane is formed of an auxetic material. In yet other embodiments, the membrane is formed of polyurethane.

In some embodiments, the membrane is separate from the first portion and is attachable thereto. In other embodiments, the first portion and the membrane are integrally formed of a single material.

In some embodiments, during application of an increasing force pushing the head unit onto the external surface, when the external surface is a flexible external surface, a contact area of the membrane with the external surface increases, resulting in a decrease of a distance between the first and second protrusions, thereby causing pinching and release of the flexible external surface between the first and second protrusions in a direction perpendicular to the main longitudinal axis.

In some embodiments, during application of force to the membrane against a rigid external surface, a configuration of a surface of the membrane is determined by a contour of the rigid external surface. In some embodiments, during application of force to the membrane and a flexible external surface, a configuration of a surface of the membrane is determined by a flexibility of the membrane and a flexibility of the flexible external surface.

In some embodiments, the membrane is asymmetrical relative to the main longitudinal axis, and has a first side having a first radius and a second side having a second radius, the second radius being larger than the first radius.

In some embodiments, the membrane has a first longitudinal dimension and a second dimension, the first longitudinal dimension being greater than the second dimension and being in a direction perpendicular to the main longitudinal axis, and the membrane is arched in a direction of the second dimension.

In some embodiments, the head unit further includes a fluid insertion portal disposed in the first connection area, the portal having an open operative orientation and a sealed operative orientation.

In some embodiments, the head unit further includes a reinforcing ring surrounding the first connection region.

In some embodiments, when the membrane is pressed against a planar external surface, initially an outer circumference of the membrane engages with the planar external surface, and subsequently inner regions of the membrane contact the planar external surface.

In some embodiments the head unit further includes a plurality of additional protrusions disposed between the first portion and the second portion of the head unit, which additional protrusions form local peripheral sealing areas at increased force. In some such embodiments, the head unit further includes at least one sealing ring adapted to increase force in the sealing areas. In some embodiments, the at least one sealing ring includes clamps adapted to engage the first portion at the sealing areas.

In accordance with another embodiment of the disclosed technology, there is provided a system including at least two head units according to any embodiment(s) disclosed hereinabove, the head units being mechanically connected to a single intermediate base, single the intermediate base including a connector adapted for connection to an actuator.

In some embodiments, an angle of at least one of the at least two head units, relative to at least a portion of the intermediate base, is adjustable.

In some embodiments, the at least two head units are fluidly connected, such that fluid can pass between cavities of the at least two head units.

In some embodiments, the intermediate base is springy.

In accordance with yet another embodiment of the disclosed technology, there is provided a method for providing treatment to a treatment surface, the method including:.

In some embodiments, the treatment surface is equivalent in structure to a surface of the human body. In some other embodiments, the treatment surface is a surface of the human body.

This disclosure should be interpreted according to the definitions below. In case of a contradiction between the definitions in this Definitions section and other sections of this disclosure, this section should prevail.

In case of a contradiction between the definitions in this section and a definition or a description in any other document, including in another document included in this disclosure by reference, this section should prevail, even if the definition or the description in the other document is commonly accepted by a person of ordinary skill in the art.

Cardinal directions are defined relative to the orientation of a head unit, during normal use with the membrane applying force in a vertical direction to the horizontal surface of a table. Thus, the "bottom" of the head unit is the portion closest to the horizontal surface of the table during such use, and adjacent the membrane of the head unit, and "top" of the head unit is the portion farthest from the horizontal surface of the table during such use, and adjacent the connection to an external device.

The term "graded" is defined as relating mainly to deformation of surfaces, to changes in the size of engagement areas between a membrane and a contact surface, and/or to motion, caused by application of force to a head unit. The term graded in the context of the present application relates to something that is not continuous, but rather occurs in multiple bursts.

Graded engagement of a membrane and a surface may occur when the membrane of a head unit includes multiple protrusions having different heights, relative to each other or relative to an upper plane of the head unit. In this case, the graded engagement occurs by initial engagement of one of the protrusions, and only subsequent engagement of another of the protrusions, resulting in a non-continuous engagement between the membrane and the surface.

As another example, a graph would be considered graded if the plot of the graph forms the shape of steps, rather than a continuous incline.

The term "amplitude" is defined as commonly used in physics, and relates to the maximal distance of the graph from a baseline, such as a zero line. For example, in a sinusoidal graph, the maximal travel, or variance, of the graph, is two amplitudes (one in the positive direction, above the baseline, and an equally sized amplitude in the negative direction, below the baseline).

An "external device" is defined as a device, operated by electrical energy or by any other type of energy, and is connectable to a head unit as which can apply a force on a surface with which it is engaged, for example as an actuator of the head unit. The operation of the external device, when it is connected to the head unit may be periodic or cyclic, such as sinusoidal.

The term "head unit" is defined as a device or unit suitable for connection to an external device, which can be, for example, an external actuator. The head unit includes the connection element and all components and parts required for operation of the device and for engagement of a surface. Typical connection types include threaded connection or snap-fit connection, as used for connection of a head unit to an external device in mechanical engineering. The head unit includes a first, upper portion, and a second, lower portion. The external device is connectable to the upper portion of the head unit.

The term "main longitudinal axis" of a head unit relates to a central longitudinal axis of the head unit, extending along the center of the first upper portion of the head unit.

The term "upper plane" relates to a virtual planar surface, perpendicular to the main longitudinal axis, and tangential to the upper edge of the head unit. An example of the upper surface is illustrated in <FIG>, at reference numeral <NUM>/2A.

The term "membrane" of a head unit is defined as an elastic portion disposed at a lower region of the head unit.

The term "protrusion of the membrane" relates to a portion of the membrane which forms a downward-facing protrusion extending downwardly from another portion of the membrane, away from the upper portion of the head unit. The protrusion may be a local protrusion, at the center of the membrane or at any other location in the membrane. The protrusion may be circumferential surrounding the main longitudinal axis, and may form a complete circumference, a segmented circumference, or an incomplete circumference. The protrusion may be elongate or circumferential at another location of the membrane, and may be complete, segmented, or incomplete. Parallel or angled sections of the protrusion, along the main longitudinal axis of the head unit, may be uniform or may be varying at different locations along the protrusion.

The term "extreme point" of a protrusion of the membrane relates to the one or more points of the protrusion having the greatest distance to the upper plane, when measured parallel to the longitudinal axis. Typically, the extreme point is defined when the membrane is at rest state, but the definition is valid also when force is applied to the membrane or the protrusion, and the protrusion is deformed. If the membrane includes multiple protrusions, denoted first protrusion, second protrusion,. , Nth protrusion, the extreme points of the protrusions are denoted first extreme point, second extreme point,. , Nth extreme point, respectively.

The term "tangential plane" of a protrusion of the membrane relates to a virtual planar surface, perpendicular to the main longitudinal axis and parallel to the upper plane, which is tangential to the extreme point of the protrusion. If the membrane includes multiple protrusions, denoted first protrusion, second protrusion,. , Nth protrusion, the tangential planes of the protrusions are denoted first tangential plane, second tangential plane,. , Nth tangential plane, respectively.

The term "height of an extreme point (of a protrusion)", "longitudinal distance of a protrusion" and "height of a protrusion" of the membrane may be used interchangeably, and relate to the distance between the tangential plane of the protrusion and the upper plane.

The term "longitudinal distance between a first protrusion and a second protrusion" of a membrane relates to the distance between the first tangential plane and the second tangential plane.

The term "equidistant membrane" defines a membrane having at least a first protrusion and a second protrusion, such that, when the membrane is in its rest state, the first tangential plane and the second tangential plane coincide. An equidistant membrane can provide graded activation, or have graded force applied thereto, by application of force against a graded surface, as illustrated in <FIG>, or by angled application of force, as illustrated in <FIG>. A membrane is considered to be equidistant even if it includes one or more third protrusions, whose tangential planes do not coincide with the first and second tangential planes.

The term "graded surface" relates to a surface having a first, lower, plane, and a second, higher, plane, connected by a third plane, perpendicular or angled relative to the first and second planes, for example as illustrated in <FIG>. The first and second planes may be horizontal, or may be angled relative to the horizontal. The first and second planes may be parallel to one another, or may be angled relative to one another, at which case the planes are considered to form a graded surface if an extreme highest point of one the lower plane, is lower than an extreme lowest point of the higher plane.

The term "angled application of force" against a planar surface relates to application of force to the head unit, against the planar surface, when the main longitudinal axis of the head unit is angled relative to an axis perpendicular to the planar surface. For example, in <FIG> force is applied to head unit <NUM>/<NUM> while main longitudinal axis <NUM>/<NUM> is angled relative to the axis <NUM>/<NUM> disposed perpendicular to the planar surface <NUM>/<NUM>.

The term "rigidity" defines how rigid a specific part or component is, which rigidity is the result of a combination of the hardness of the material used for forming the part or component, and the geometrical shape and dimensions of the part, at different portions thereof.

The foregoing discussion will be understood more readily from the following detailed description of the invention, when taken in conjunction with the accompanying <FIG>), in which:.

Examples illustrative of embodiments of the invention are described below with respect to the figures attached hereto. In the figures, identical structures, elements or parts that appear in more than one figure are generally labeled with the same numeral in all figures in which they appear.

Reference is made to all figures constructed and operative under a preferred embodiment of the present invention
<FIG> is a partially sectional schematic diagram of a device according to an embodiment of the present invention, which includes actuator having a head unit including a graded membrane, the head unit being illustrated as a sectional illustration. As seen, the device includes an actuator <NUM>/<NUM> having a head unit <NUM>/<NUM>, the head unit including a graded membrane <NUM>/<NUM> at a bottom portion thereof.

<FIG> is a sectional illustration of a head unit <NUM>/2A according to an embodiment of the present invention. The head unit including at least three portions having different rigidity parameters. The first portion, illustrated as the upper portion of the head unit, includes a first connection region <NUM>/2A adapted for connection to an external device, such as actuator <NUM>/<NUM> of <FIG>. The first portion is typically the most rigid of the three portions.

A main longitudinal axis <NUM>/2A of the first portion, extending through the first connection region <NUM>/2A defines a main longitudinal axis of the head unit. An upper plane <NUM>/2A, perpendicular to main longitudinal axis <NUM>/2A, is defined at an upper edge of first connection region <NUM>/2A.

An intermediate portion <NUM>/2A is disposed between the first connection region <NUM>/<NUM> and a membrane <NUM>/2A, and may have a different rigidity parameters than the first and second portions. Typically, the intermediate portion <NUM>/2A is less rigid than the first connection region <NUM>/2A and more rigid than the membrane <NUM>/2A.

Membrane <NUM>/2A forms the second portion of the head unit, and is attached to the intermediate portion <NUM>/2A distally to the first connection region. The membrane may be attached to the intermediate portion using any suitable mechanism, such as by mechanical attachment (e.g. using threaded attachment or snap fit attachment), by adhesive attachment, or by soldering. Membrane <NUM>/2A includes a first, central, protrusion terminating at a first extreme point <NUM>/2A, and a second, circumferential protrusion, terminating at second extreme points <NUM>/2A. A first tangential plane <NUM>/2A is perpendicular to main longitudinal axis <NUM>/2A at first extreme point <NUM>/2A, and a second tangential plane <NUM>/2A is perpendicular to main longitudinal axis <NUM>/2A at second extreme points <NUM>/2A.

Although the first protrusion is illustrated as being disposed at the center of the membrane, an equivalent protrusion may also be disposed close to, or adjacent, the center of the membrane, and not necessarily directly at the center.

Although the second protrusion is illustrated as being concentric with the first protrusion, it need not necessarily be so, and need not necessarily be centered about the main longitudinal axis of the head unit.

Membrane <NUM>/2A, which defines the second portion of the head unit, is less rigid than the first portion and first connection region <NUM>/2A, and is also softer with respect to a spring action thereof. In some embodiments, the first portion may, for example, have a shore A hardness in the range of <NUM> to <NUM>, or a shore A hardness of <NUM>. In some embodiments, the second portion and/or the membrane may, for example, have a shore A hardness in the range of <NUM>-<NUM>, or a shore A hardness of <NUM>. The shore A value of the first portion and of the second portion is dependent on the characteristics of the materials from which these portions are formed, and of the thickness and the geometry of each portion.

Membrane <NUM>/2A may be formed of any suitable elastic and flexible material. For example, in some embodiments, the membrane is formed of a rubber material. In some such embodiments, the rubber material may include an electrical additive which decreases its electrical resistance. In some such embodiments, the rubber material may include a magnetic additive, which increases the rubber's ability to function as a magnet. In some embodiments, the rubber material changes its mechanical properties when an electrical current is passed therethrough.

In some embodiments, the membrane may be formed of silicone. In some embodiments, the membrane may be formed of a viscoelastic material. In some embodiments, the membrane may be formed of an auxetic material. In some embodiments, the membrane may be formed of polyurethane.

It is appreciated that the difference in rigidity between the first portion, including the first connection region, and the membrane, as well as the materials from which the membrane can be manufactured, apply to all embodiments of head units described hereinbelow, and for brevity the discussion is not repeated for each embodiment shown.

During typical use of the head unit, for example for treatment of a treatment surface, the head unit percusses or is otherwise moved in a direction indicated by reference numeral <NUM>/2A in a periodic manner, characterized by at least one amplitude and at least one frequency. In some embodiments, the amplitude is in the range of <NUM> to several tens of mm, for example <NUM> to <NUM>. In some embodiments, the frequency is in the range of <NUM> to <NUM>.

Most of the head units described hereinabove and hereinbelow are suitable for providing mechanical and physical motion relative to a treatment surface engaging the membrane. In use, a head unit as described hereinabove and hereinbelow, is connected to an external actuator via the first connection region <NUM>/2A which forms part of the rigid portion of the head unit. The membrane of the head unit engages the external treatment surface. The actuator is then operated such that current provided by the actuator causes motion, or percussion, of the membrane against the treatment surface. The actuator operates in a periodic manner and is characterized by at least one amplitude and at least one frequency, which determine the characteristics of the motion or percussion. The treatment is provided in a graded manner, which graded manner may be a result of any one or more of: the geometry of the surface, the geometry of the membrane, and an angle of application of force to the surface. As shown in various examples hereinbelow, the external treatment surface may be rigid or flexible. Additionally, the external surface may be planar, curved, or may have any other suitable contour.

<FIG> is a sectional illustration of a head unit <NUM>/2B according to an embodiment of the present invention, having at least two portions having different rigidities. The first portion, which is illustrated as the upper portion of the head unit, includes a first connection region <NUM>/2B adapted for connection to an external device, such as actuator <NUM>/<NUM> of Figure No. <NUM>. The main longitudinal axis <NUM>/2B of the head unit extends through the first connection region <NUM>/2B. An upper plane <NUM>/2B is at an upper end of first connection region <NUM>/2B, perpendicular to the main longitudinal axis.

A membrane <NUM>/2B, forming the second portion, is attached via an intermediate portion, to first connection region <NUM>/2B. The membrane <NUM>/2B includes first and second protrusions, here illustrated as conical protrusions terminating in spherical ends. The first conical protrusion <NUM>/2B defines a first extreme point <NUM>/2B, and a first tangential plane <NUM>/2B. The second conical protrusion <NUM>/2B defines a second extreme point <NUM>/2B and a second tangential plane <NUM>/2B. In the illustrated embodiment, the second tangential plane <NUM>/2B is coincidental with an external treatment plane <NUM>/2B, onto which force is to be applied by the head unit.

As seen, the first height of first protrusion <NUM>/<NUM> is smaller than the second height of second protrusion <NUM>/2B, which extends further downward from the membrane connection point than the first protrusion. The distance between the first and second protrusions is indicated by reference numeral <NUM>/2B.

While two conical protrusions are illustrated in <FIG>, it is appreciated that the membrane may also include more than two such protrusions, which may also have different heights or distances, as defined using the same terminology and definitions, as also provided hereinabove.

In use, an external force is applied to head unit <NUM>/2B in the direction of arrow <NUM>/2B and a direction of motion of head unit <NUM>/2B, as described in further detail hereinbelow. At first, there is no contact between the second, longer protrusion <NUM>/2B and the external treatment plane <NUM>/2B. As the head unit <NUM>/2B moves in the direction of arrow <NUM>/2B, second protrusion <NUM>/2B engages the external treatment plane <NUM>/2B and is pressed thereon, such that the contact area between the second protrusion <NUM>/2B and the treatment plane <NUM>/2B expands. This type of expansion is typical of flexible conical structures, which the force applied thereto, against a surface, increases. As the head unit <NUM>/2B continues to move in the direction of arrow <NUM>/2B, also first protrusion <NUM>/2B engages the external treatment plane <NUM>/2B and is pressed thereon, such that the contact area between the first protrusion <NUM>/2B and the treatment plane <NUM>/2B expands. Because of the distinct heights of the two protrusions, the engagement of the treatment plane and the force applied thereto are graded, and non-continuous, until the formation of a substantial contact area.

Stated differently, as head unit is continuously moved in the direction of arrow <NUM>/2B towards and/or against treatment plane <NUM>/2B, during the application of force, there will be a transition between the contact with the second protrusion and the contact with the first protrusion, resulting in graded and non-continuous contact between the membrane <NUM>/2B and the external treatment plane <NUM>/2B.

<FIG> is a sectional illustration of a head unit <NUM>/2C, similar to the head unit <NUM>/2A, and defining a main longitudinal axis <NUM>/2C and an upper plane <NUM>/2C. Head unit <NUM>/2C includes an equidistant membrane <NUM>/2C having a first protrusion <NUM>/2C terminating at a first extreme point <NUM>/2C, and a second protrusion <NUM>/2C terminating at a second extreme point <NUM>/2C. As seen, when no force is applied to head unit <NUM>/2C, and membrane <NUM>/2C is at rest state, the first and second protrusions have the same height, or longitudinal distance, from the upper plane <NUM>/2C.

<FIG> shows the head unit head unit <NUM>/2C of <FIG>, where the first and second protrusions <NUM>/2C and <NUM>/2C are equally pressed against an external treatment plane <NUM>/2D, following movement of the head unit <NUM>/2C toward the treatment plane along the longitudinal direction of the head unit. The distance traversed by the head unit, toward the treatment plane <NUM>/2D, is indicated by reference numeral <NUM>/2D. As seen, in some cases, when the protrusions of equidistant membrane <NUM>/2C are pressed onto a surface, the membrane remains equidistant, and the distant between the contact areas of the protrusions with the treatment surface, and the upper plane <NUM>/2C, remains fixed.

<FIG> shows the head unit <NUM>/2C of <FIG>, engaging a graded surface having a first, higher, plane <NUM>/2E, and a second, lower plane <NUM>/2E. As seen, when force is applied to head unit <NUM>/2C toward the graded surface, initially, second protrusion <NUM>/2C engages, and is pressed against, the higher plane <NUM>/2E of the graded surface, while the first protrusion <NUM>/2C is disposed above, and does not engage, lower plane <NUM>/2E. Movement of the head unit <NUM>/2C along the graded surface, in a direction indicated by arrow <NUM>/2E, while continuing to apply force to the head unit, results in the state illustrated in <FIG> and described hereinbelow.

<FIG> shows the head unit <NUM>/2C of <FIG> adjacent the graded surface of <FIG>, following motion of the head unit along the graded surface in the direction indicated by arrow <NUM>/2E in <FIG>. As seen, following motion of the head unit, both protrusions <NUM>/2C and <NUM>/2C engage, and are pressed against, the higher surface <NUM>/2E of the graded surface, such that, with respect to the higher plane <NUM>/2E, the position of head unit <NUM>/2C is identical to that illustrated in <FIG>. It is appreciated that the manner of force application to a graded surface, described herein with respect to <FIG>, results in graded application of force even though the membrane <NUM>/2C is an equidistant membrane, as defined above.

<FIG> shows the head unit <NUM>/2C of <FIG>, during angled application of force against an external treatment plane <NUM>/<NUM>. As seen, the main longitudinal axis <NUM>/2C of the head unit <NUM>/2C is tilted in a direction <NUM>/<NUM> to be at an angle α relative to a virtual axis <NUM>/<NUM> which is perpendicular to treatment plane <NUM>/<NUM>. As such, when force is applied to the head unit <NUM>/2C in the direction of longitudinal axis <NUM>/2C, the second protrusion <NUM>/2C is pressed against plane <NUM>/<NUM>, while the first protrusion <NUM>/2C remains above the plane <NUM>/<NUM>, and at a distance <NUM>/<NUM> therefrom. It is appreciated that if the head unit <NUM>/2C were tilted in the opposing direction, for example for main longitudinal axis <NUM>/2C to form an angle -α relative to a virtual axis <NUM>/<NUM>, the first protrusion <NUM>/2C would be pressed against surface <NUM>/<NUM>, while the second protrusion <NUM>/<NUM> would remain above the surface.

<FIG> shows the head unit <NUM>/2C of <FIG> adjacent the planar surface <NUM>/<NUM> of <FIG>, following tilting of the head unit <NUM>/2C in a direction <NUM>/<NUM>, which causes the longitudinal axis <NUM>/2C of the head unit to coincide with the virtual longitudinal axis <NUM>/<NUM>, and to be perpendicular to plane <NUM>/<NUM>. As seen, following such tilting motion of the head unit, both protrusions <NUM>/2C and <NUM>/2C engage, and are pressed against, the external plane <NUM>/<NUM>, such that, with respect to surface <NUM>/<NUM>, the position of head unit <NUM>/2C is identical to that illustrated in <FIG>. It is appreciated that the angled application of force, described herein with respect to <FIG>, results in graded application of force even though the membrane <NUM>/2C is an equidistant membrane, as defined above.

<FIG> is a schematic illustration of a fast connector <NUM>/<NUM> for connection of a head unit according to the present invention to an external device, such as an actuator. The fast connector <NUM>/<NUM> includes a rotation preventing mechanism <NUM>/<NUM>, and is illustrated in a closed position of the connector.

<FIG> is a schematic illustration of the fast connector <NUM>/<NUM> of <FIG>, where rotation preventing mechanism <NUM>/<NUM> is in a rotation-prevented, pre-locked position.

<FIG> is a bottom view planar illustration <NUM>/<NUM> a head unit <NUM>/<NUM> according to the present invention, which head unit is illustrated in <FIG>.

<FIG> is a sectional illustration of a head unit <NUM>/<NUM> according to an embodiment of the present invention. Head unit <NUM>/<NUM> includes a membrane <NUM>/<NUM> having a downward facing curved surface <NUM>/<NUM>. The spherical surface <NUM>/<NUM> includes a peripheral and circumferential protruding ring <NUM>/<NUM>, which terminates at a sharp end.

<FIG> is a top view planar illustration <NUM>/<NUM> of the head unit <NUM>/<NUM> of <FIG>.

<FIG> is a sectional illustration of a head unit <NUM>/<NUM> including a membrane <NUM>/<NUM>, which membrane has a downward facing, outwardly protruding curved surface. In typical use, force is applied to the head unit, pushing the membrane against a contact surface, or treatment surface. The contact surface may be flexible or rigid. When the applied force grows, a balance between the flexibility of the contact surface and the flexibility of the membrane determines the shape or configuration of the bottom surface of the membrane.

In some embodiments, when the applied force is continuously increased, an engagement area at which the membrane engages the contact surface also continuously increases.

<FIG> is a sectional illustration of a head unit <NUM>/<NUM> including a membrane <NUM>/<NUM> having a flat planar downward facing surface <NUM>/<NUM>.

<FIG> is a schematic view of an asymmetrical membrane <NUM>/<NUM> suitable for use in a head unit according to embodiments of the present invention. As seen, membrane <NUM>/<NUM> includes a first side <NUM>/<NUM> having a first radius, and a second side <NUM>/<NUM> having a second radius, where the second radius is smaller than the first radius.

<FIG> is a sectional illustration of an asymmetrical head unit <NUM>/<NUM>, whose peripheral shape, or membrane, is depicted in <FIG>. A lower surface <NUM>/<NUM> of the membrane of head unit <NUM>/<NUM> is curved, or spherical. The membrane includes a peripheral protruding ring <NUM>/<NUM>, which terminates at a sharp end. Protruding ring <NUM>/<NUM> causes the engagement area between the membrane and a contact surface to be gradually increased, when force is applied to the membrane. Additionally, ring <NUM>/<NUM> assists in preserving a material, such as a treatment gel or cream, which was spread on the membrane or on the head unit prior to use thereof, from being spread outside of the engagement area.

<FIG> is a bottom view planar illustration <NUM>/<NUM> of head unit <NUM>/<NUM> illustrated in <FIG>.

<FIG> is a sectional illustration of a head unit <NUM>/<NUM> arranged about a main longitudinal axis <NUM>/<NUM>. The head unit includes a membrane <NUM>/<NUM> having a graded contact surface defined by a central protrusion <NUM>/<NUM> and a circumferential protrusion <NUM>/<NUM>. When head unit <NUM>/<NUM> is pushed in the direction of arrow <NUM>/<NUM> using a continuously increasing force, membrane <NUM>/<NUM> engages an external surface <NUM>/<NUM>. The engagement area between the external surface and the membrane is gradual, and is staggered based on the structure of the protrusions <NUM>/<NUM> and <NUM>/<NUM> of the membrane.

<FIG> is a bottom view planar illustration of a membrane <NUM>/<NUM>, suitable for use in the head unit of <FIG>. Axes <NUM>/<NUM> and <NUM>/<NUM> are virtual axes used to assist in identification of heights, distances, and other relative dimensions. The circumferential portion <NUM>/<NUM>, which may be similar to circumferential protrusion <NUM>/<NUM> of <FIG>, is bound by interior contour <NUM>/<NUM> and exterior contour <NUM>/<NUM>. While contours <NUM>/<NUM> and <NUM>/<NUM> are illustrated as circular contours, it is appreciated that they may have other shapes as well, provided that they are closed contours.

Circumferential portion <NUM>/<NUM> includes four waves, in a direction surrounding the main longitudinal axis of the head unit, such as axis <NUM>/<NUM> of <FIG>. In some embodiments, the circumferential portion <NUM>/<NUM> may be sinusoidal, and may have four maximum points and four minimum points, where all the maximum points are equidistant to an upper plane of the head unit and all the minimum points are equidistant to the upper plane of the head unit. In another embodiment, the circumferential portion <NUM>/<NUM> may have waves of varying dimensions. For example, the circumferential portion <NUM>/<NUM> may include four maximum points <NUM>/<NUM> all being equidistant to the upper plane of the head unit. Two local minimum points <NUM>/<NUM> are equidistant relative to the upper plane of the head unit, such that the distance of points <NUM>/<NUM> from the upper plane is greater than the distance of points <NUM>/<NUM> from the upper plane. Two absolute minimum points <NUM>/<NUM> are equidistant relative to the upper plane of the head unit, such that the distance of points <NUM>/<NUM> from the upper plane is greater than the distance of points <NUM>/<NUM> from the upper plane.

Similarly to that described hereinabove with respect to <FIG>, when force is applied to a head unit including membrane <NUM>/<NUM>, pushing the membrane toward an external surface, the first points to contact and be pressed against the external surface will be absolute minimum points <NUM>/<NUM>. As additional force is applied, also local minimum points <NUM>/<NUM> will press against the surface, and maximum points <NUM>/<NUM> will be the last to engage the surface, and the contact area with the surface will increase. Thus, the membrane of <FIG> is suitable for graded application of force to a surface.

<FIG> is a sectional illustration of a head unit <NUM>/<NUM> according to an embodiment of the present invention, the head unit being defined about a main longitudinal axis <NUM>/<NUM> and defining an upper plane <NUM>/<NUM>. Head unit <NUM>/<NUM> includes a membrane <NUM>/<NUM> having a first, central, protrusion <NUM>/<NUM> defining a first extreme point <NUM>/<NUM>, a second, circumferential protrusion <NUM>/<NUM>, concentric to first protrusion <NUM>/<NUM> and defining second extreme points <NUM>/<NUM>, and a third, circumferential protrusion <NUM>/<NUM>, concentric to the first and second protrusions, and defining third extreme points <NUM>/<NUM>. The first height of first protrusion <NUM>/<NUM> is greater than the second height of second protrusion <NUM>/<NUM>, which in turn is greater than the third height of third protrusion <NUM>/<NUM>.

During application of a force in direction <NUM>/<NUM> to head unit <NUM>/<NUM> against a planar external surface <NUM>/<NUM>, an engagement area at which membrane <NUM>/<NUM> engages the external surface <NUM>/<NUM> increases, due to contraction of the membrane as indicated by arrows <NUM>/<NUM>.

External surface <NUM>/<NUM> may have different configurations, and may be similar to a surface of the human body or may be a surface of the human body, for example during physiotherapy or other treatments.

In embodiments in which the external surface is flexible, when force is applied to the head unit <NUM>/<NUM> such that the membrane <NUM>/<NUM> presses against the external surface, a balance between the flexibility of the external surface and the flexibility of the membrane determines the shape or configuration of the bottom surface of the membrane. When there is a change in the force applied, the configuration of the membrane changes accordingly. Thus, if the external surface <NUM>/<NUM> illustrated in <FIG> were flexible, the configuration of the membrane, and the engagement area between the membrane and the external surface, would be different from that illustrated, due to the flexibility of the contact surface. For example, the surface of a body portion of a patient, such as the surface of their arm, abdomen, or foot, may be considered flexible surfaces.

As force is released and the membrane <NUM>/<NUM> moves away from the external surface <NUM>/<NUM>, the engagement area decreases to the point of complete separation between the membrane and the external surface, at which time the membrane surface is at, or near, a rest state similar to that illustrated.

In some embodiments, during application of an increasing force to the head unit pushing against a flexible external surface, a contact area of the membrane with the flexible external surface increases, resulting in a decrease of a distance between the first and second protrusions. As a result, the flexible external surface is pinched and released between the first and second protrusions, in a direction perpendicular to the main longitudinal axis.

<FIG> is a sectional illustration of a head unit <NUM>/<NUM>, similar to the head unit of <FIG>, following application of force thereto in the direction <NUM>/<NUM>. As seen in <FIG>, the protrusions <NUM>/<NUM>, <NUM>/<NUM>, and <NUM>/<NUM> have been pressed against planar external surface <NUM>/<NUM>. As explained above, the transition from the configuration shown in <FIG>, to that shown in <FIG>, is dictated by the force applied to the head unit pushing the membrane <NUM>/<NUM> against the external surface <NUM>/<NUM>. As the force increases, due to the balance between the flexibility of the external surface and the flexibility of the membrane, as well as due to the structure of the membrane, the increase in the engagement area between the membrane and the external surface is graded and discontinuous. As mentioned above, in this embodiment, the flexibility or rigidity of the external surface substantially dictates the configuration of the membrane.

<FIG> is a partial sectional illustration of a device including two head units <NUM>/<NUM> according to the present invention, similar to the head units illustrated in <FIG>. In the illustrated embodiment, the head units <NUM>/<NUM> are mechanically connected to an intermediate base plate <NUM>/<NUM>, by screws <NUM>/<NUM>, although any other suitable method of connection of the head units to the intermediate base plate is considered within the scope of the present invention. Intermediate base plate <NUM>/<NUM> is arranged about a main axis <NUM>/<NUM>, via which the base plate may be connected to an actuator, such as, for example, actuator <NUM>/<NUM> of <FIG>. The base plate <NUM>/<NUM> is adapted to be connected to the actuator using any suitable mechanism, such as by threaded connection or by snap fit connection.

A generally planar external surface <NUM>/<NUM> which is adapted to be engaged by head units <NUM>/<NUM>, includes a protrusion, or bulge, <NUM>/<NUM> extending outwardly therefrom. This configuration may occur, for example, in an area of skin along the spine of a patient. When force is applied to the intermediate base plate <NUM>/<NUM> and/or to head units <NUM>/<NUM>, in a longitudinal direction toward external surface <NUM>/<NUM>, the head units close the distance <NUM>/<NUM> and are pressed against external surface <NUM>/<NUM>.

<FIG> is a partial sectional illustration of the device of <FIG>, where head units <NUM>/<NUM> are pressed against external surface <NUM>/<NUM>, similarly to the configuration illustrated in <FIG>. In the illustrated embodiment, the head units press against external surface <NUM>/<NUM>, but do not apply force to the protrusion <NUM>/<NUM>. The configuration illustrated in <FIG> may be reached by applying additional force to the configuration shown in <FIG>, such that the membranes of head units <NUM>/<NUM> fully engage the external surface <NUM>/<NUM>. However, also in the configuration of <FIG>, undesired contact with the protrusion, which may for example represent skin along the spine of a subject, is prevented.

Figure No. <NUM> is a perspective view illustration of intermediate base plate <NUM>/<NUM> shown in <FIG>, including an axial connector <NUM>/<NUM> thereof, which is arranged about main axis <NUM>/<NUM>.

<FIG> illustrates a structure <NUM>/<NUM> similar to that of <FIG>. The main difference between <FIG> and <FIG> is that in <FIG>, cavities or hollows <NUM>/<NUM> of the two head units <NUM>/<NUM> are interconnected by a passage <NUM>/<NUM>, allowing fluid flow between the two head units. <FIG> illustrates a configuration which exists prior to application of force to the head units.

<FIG> illustrates the structure <NUM>/<NUM> of <FIG>, following application of a force in a direction <NUM>/<NUM> to the structure, which force causes structure <NUM>/<NUM>, and specifically head units <NUM>/<NUM>, to approach and/or engage an external surface <NUM>/<NUM> by closing the space <NUM>/<NUM> shown in <FIG>. One of the characteristics of this structure is the ability to bypass, or avoid, protrusion <NUM>/<NUM> which is present in external surface <NUM>/<NUM>, and is similar to protrusion <NUM>/<NUM> of <FIG>.

<FIG> is a perspective view illustration of an intermediate base plate <NUM>/<NUM>, used to connect the head units of <FIG>. Intermediate base plate <NUM>/<NUM> is similar in structure to intermediate base plate <NUM>/<NUM> of <FIG>.

<FIG> is a perspective view illustration of a head unit <NUM>/<NUM> according to another embodiment of the present invention. Head unit <NUM>/<NUM> includes a longitudinal membrane <NUM>/<NUM>, adapted to engage an external contact surface of an elongate body <NUM>/<NUM>, such as a human arm or leg. The structure of membrane <NUM>/<NUM>, which is elongate in one direction, and curved in the transverse direction, allows for compatibility of contact with elongate body <NUM>/<NUM>, which compatibility is at least in part due to the flexibility of the elongate body <NUM>/<NUM> and the flexibility of the membrane <NUM>/<NUM>.

When force applied to the head unit, pushing it against the external surface of the elongate body <NUM>/<NUM>, is increased, there is an increase in the size of an engagement area at which the membrane engages the external surface.

The external surface of the elongate body <NUM>/<NUM> may have different spatial configurations. In some embodiments, the external surface may be similar to a surface of a human body part, or may actually be a surface of a human body part.

<FIG> is a partial sectional illustration of a device <NUM>/<NUM> including two head units <NUM>/<NUM>, both of which are connected to an intermediate base plate. The intermediate base plate includes a first segment <NUM>/<NUM> including the first connection region for connection to an external device, as well as second and third segments <NUM>/<NUM> that are pivotable relative to the first segment, about axes <NUM>/<NUM>. Each of the two head units <NUM>/<NUM> is attached to one of the second and third segments <NUM>/<NUM>. Extending from the first segment <NUM>/<NUM> of the intermediate base plate, on both sides thereof, are extension plates <NUM>/<NUM>, each of which includes three bores <NUM>/<NUM>. Each of the second and third segments <NUM>/<NUM> of the intermediate base plate, as well as the head units <NUM>/<NUM> connected thereto, may be at one of three angular orientations relative to the first segment <NUM>/<NUM> of the intermediate base plate, where the angular orientation is dependent on the specific bore <NUM>/<NUM> which is in engagement with the second or third segments.

The membranes of head units <NUM>/<NUM> are illustrated in two operative orientations with respect to a body having a curved or hemispherical surface <NUM>/<NUM>. In the orientation indicated by reference numeral <NUM>/<NUM>, no force is applied to the membrane, and the membrane assumes the shape it has in rest state. By contrast, in the orientation indicated by reference numeral <NUM>/<NUM>, force is applied to the membranes, for example via application of force to the intermediate base plate, and the membranes engage surface <NUM>/<NUM>.

<FIG> is a partial sectional illustration of a system <NUM>/<NUM> including two head units <NUM>/<NUM> that are connected to an intermediate base plate <NUM>/<NUM>. The intermediate base plate <NUM>/<NUM> is flexible and springy, and is similar to that shown in <FIG> in that the head units are angled relative to the center of the base plate. However, in the embodiment of <FIG>, the angle of the head units <NUM>/<NUM> is determined by the spring-based pivoting facilitated by the intermediate base plate. The membranes of the head units <NUM>/<NUM> are shown in two operative orientations relative to a body having a hemispherical surface <NUM>/<NUM>, as described hereinabove with respect to <FIG>.

<FIG> is a planar, side view illustration of a spring device <NUM>/<NUM> that can be used as the intermediate base plate of Figure no. The arrangement of <FIG> enables changing of the flexibility and or springiness of the two head units by changing the location of the head units to any of three leveled options <NUM>/<NUM>, shown as an example. This type of spring systems is commonly used in the automotive industry.

<FIG> is a sectional illustration of a head unit <NUM>/<NUM>, similar to that shown in <FIG>, where the membrane <NUM>/<NUM> thereof is in rest state, without any application of force thereto. Membrane <NUM>/<NUM> of head unit <NUM>/<NUM> may be relatively flexible or relatively rigid, and mechanically connects to intermediate portion <NUM>/<NUM> of the head unit. As the force applied to the head unit is increased, the engagement area between protrusions <NUM>/<NUM>, <NUM>/<NUM>, and <NUM>/<NUM> of the membrane and an external plane <NUM>/<NUM> are increased in a graded and discontinuous manner.

The illustrated head unit <NUM>/<NUM> has a liquid <NUM>/<NUM> disposed therein, which liquid may be of different types and typically fills the membrane. The liquid is inserted into the head unit via a portal <NUM>/<NUM>. Following insertion of the fluid, the portal is sealed using a sealing screw <NUM>/<NUM>, thereby to create initial air pressure in the internal volume <NUM>/<NUM> created, when the membrane is in rest state, between the seal and the liquid within <NUM>/<NUM> the head unit. As seen, in this configuration, the height of the cavity <NUM>/<NUM> is indicated by reference numeral <NUM>/<NUM>.

<FIG> is a sectional illustration of head unit <NUM>/<NUM> of <FIG>, following application of force thereto in a direction <NUM>/<NUM> shown in <FIG>. In the configuration of <FIG>, the membrane <NUM>/<NUM> is pressed onto an external surface <NUM>/<NUM>. The increase in force causes the initial height of cavity <NUM>/<NUM> to decrease from height <NUM>/<NUM> of <FIG> to a height indicated by reference numeral <NUM>/<NUM>, thus reducing the dimension of cavity <NUM>/<NUM> and increasing the pressure therein. This results in the engagement area between the membrane and the external surface <NUM>/<NUM> including most of each of the protrusions <NUM>/<NUM>, <NUM>/<NUM>, and <NUM>/<NUM>.

<FIG> is an enlarged sectional illustration of the filling portal shown in <FIG>. The head unit <NUM>/<NUM> includes an internal connector <NUM>/<NUM> forming at least part of the first connection region for connection to an external device, such as actuator <NUM>/<NUM> of <FIG>. The head unit <NUM>/<NUM> further includes the filling portal as illustrated in Figure no. <NUM>, as well as a seal <NUM>/<NUM>, which seals the portal, and may be similar to seal <NUM>/<NUM> of <FIG>. The hollow of head unit may be filled via the portal by any suitable fluid, which may include only liquid, a mixture of liquid and gas, or condensed gas such as condensed air.

<FIG> is a sectional illustration of a head unit <NUM>/<NUM> where the entirety of the head unit, including membrane <NUM>/<NUM>, is formed as a single an integral part, for example by three dimensional printing. Use of such an integrally formed head unit may resolve problems that may arise from the need to form a seal between the first portion of the head unit and the membrane.

In some embodiments, a clamping ring <NUM>/<NUM> is disposed about the first portion of the head unit <NUM>/<NUM>, so as to reinforce the first portion of the head unit indicated by arrow <NUM>/<NUM>. The intermediate portion of the head unit is indicated by arrow <NUM>/<NUM>, and the second portion of the head unit is defined by arrow <NUM>/<NUM>, which includes the membrane <NUM>/<NUM>.

In some embodiments, a portal <NUM>/<NUM> for filling the cavity of the head unit with fluid is provided within a wall of the head unit, for example in region <NUM>/<NUM> thereof. The portal may be sealed using a seal <NUM>/<NUM>.

<FIG> is a sectional illustration of the first, upper portion <NUM>/<NUM> of the head unit <NUM>/<NUM> of <FIG>, without clamping ring <NUM>/<NUM>.

<FIG> is a sectional illustration, taken along section line B-B of <FIG>, of first, upper portion <NUM>/<NUM> of the head unit <NUM>/<NUM>, following tightening of the clamping ring <NUM>/<NUM>. The use of clamping rings, as illustrated herein, is common and acceptable in the field of hydraulic piping.

<FIG> presents a top view planar view illustration of the head unit of <FIG>, following tightening of the ring <NUM>/<NUM>.

<FIG> is a sectional illustration of a head unit <NUM>/<NUM> according to a further embodiment of the present invention. Head unit <NUM>/<NUM> includes a membrane <NUM>/<NUM>, whose outer peripheral edges <NUM>/<NUM> are the first to come into contact with an opposing external surface <NUM>/<NUM>, when force is applied to the head unit pressing it toward the external surface. In the illustrated embodiment, the external surface <NUM>/<NUM> is planar. In some such embodiments, the force causes the interior pressure within a cavity <NUM>/<NUM> of the head unit to be greater than an atmospheric pressure outside the head unit.

<FIG> is a sectional illustration of head unit <NUM>/<NUM> of <FIG>, following application of force thereto, against external surface <NUM>/<NUM>, in a direction indicated by arrow <NUM>/<NUM>. As in, when force is applied to the head unit, initially outer peripheral edges <NUM>/<NUM> of the membrane engage the opposing external surface <NUM>/<NUM>. As the force in direction <NUM>/<NUM> is increased, the force on the head unit is correspondingly increased resulting in an increase in pressure within the internal volume <NUM>/<NUM> of the head unit, which decreases in height. As such, further portions of the membrane, indicated by reference numerals <NUM>/<NUM>, may engage the external surface <NUM>/<NUM>. When the contact surface is not planar, the membrane configuration can be adjusted to match the surface. This may be important, for example, for treatment of the surface of a human knee.

<FIG> is a sectional illustration of a head unit <NUM>/<NUM> having a flat rubber end <NUM>/<NUM>, distal to an upper surface <NUM>/<NUM> of the head unit.

<FIG> is a sectional illustration of a head unit <NUM>/<NUM> according to yet another embodiment of the present invention, having a rubber tip <NUM>/<NUM> including a protruding circumferential border <NUM>/<NUM>, the rubber tip <NUM>/<NUM> being distal to an upper surface <NUM>/<NUM> of the head unit.

<FIG> is a sectional illustration of a head unit <NUM>/<NUM> according to a further embodiment of the present invention, including a membrane <NUM>/<NUM>. The head unit <NUM>/<NUM> is formed of an upper section <NUM>/<NUM> and a lower portion <NUM>/<NUM>, which together define an inner cavity <NUM>/<NUM>. The upper and lower sections may be adhered to one another at an engagement region <NUM>/<NUM> thereof. In its rest state, membrane <NUM>/<NUM> includes a central protrusion <NUM>/<NUM> and a circumferential protrusion <NUM>/<NUM>, where central protrusion <NUM>/<NUM> has a greater height than circumferential protrusion <NUM>/<NUM>.

<FIG> is a sectional illustration of head unit <NUM>/<NUM> of <FIG>, when force is applied to the head unit in a direction indicated by arrow <NUM>/<NUM>, pressing the membrane against an external surface <NUM>/<NUM>. The force applied to the head unit dictates the configuration of the protrusions <NUM>/<NUM> and <NUM>/<NUM> of the membrane, when they engage the external surface.

<FIG> are sectional illustrations of head units similar to those illustrated in <FIG>, having different dimensions than the corresponding head units of <FIG>. Additionally, each of the head units of <FIG> has two circumferential dimensions along the length thereof - a greater diameter in an upper part of the head unit, and a smaller diameter in a lower part of the head unit.

<FIG> is a sectional illustration of an area of a head unit at which the intermediate portion <NUM>/<NUM> of the head unit, which is more rigid, connects to the more flexible membrane <NUM>/<NUM> of the head unit. In the illustrated embodiment, the seal between the intermediate portion <NUM>/<NUM> and the membrane <NUM>/<NUM> is formed using circumferential protrusions <NUM>/<NUM>, which are based on the principle of O-rings and which form part of membrane <NUM>/<NUM>.

<FIG> is a sectional illustration of membrane <NUM>/<NUM> of <FIG>, before it is attached to the intermediate portion of the head unit.

<FIG> is a sectional illustration of a membrane <NUM>/<NUM>, similar to that of <FIG>, having an inner reinforcing ring <NUM>/<NUM> attached thereto so as to reinforce the sealing area <NUM>/<NUM>.

<FIG> is a sectional illustration of the connection area between an intermediate portion <NUM>/<NUM> of the head unit and membrane <NUM>/<NUM> of <FIG>, which includes inner reinforcing ring <NUM>/<NUM>.

<FIG> is a sectional illustration of a membrane <NUM>/<NUM>, similar to membrane <NUM>/<NUM> of <FIG>, including an inner reinforcing ring <NUM>/<NUM>. The reinforcing ring <NUM>/<NUM> is locked into membrane <NUM>/<NUM> by a jagged edge <NUM>/<NUM> of the reinforcing ring, and a corresponding jagged edge <NUM>/<NUM> of the membrane. The main function of the reinforcing ring is to make it difficult to remove the membrane from the remainder of the head unit.

<FIG>, illustrate head units and membranes in which the engagement regions, or pressure zones, of the membrane include protrusions which are straight and perpendicular to each other, as opposed to the central and circumferential protrusions of the previous embodiments. The heights of the pressure zones, or protrusions, of the membrane, determine the flexibility at the engagement regions, where higher protrusions provide a more flexible engagement region.

<FIG> is a planar bottom view illustration of a head unit <NUM>/<NUM> having a membrane <NUM>/<NUM>, which includes engagement regions or protrusions <NUM>/<NUM> which are illustrated as vertical lines and pressure zones or protrusions <NUM>/<NUM> which are illustrated as horizontal lines, perpendicular to protrusions <NUM>/<NUM>, and replace the previously shown circumferential rings forming pressure zones.

<FIG> is a sectional illustration of the membrane of the head unit of <FIG>, where the protrusions <NUM>/<NUM> have a small height, and are relatively rigid.

<FIG> is a sectional illustration of the membrane of the head unit of <FIG>, where the protrusions <NUM>/<NUM> have a greater height, and as such are more flexible, than the protrusions <NUM>/<NUM> of <FIG>.

<FIG> is a top view planar illustration of the head unit <NUM>/<NUM> of <FIG>. This top view demonstrates that the upper portion of head unit <NUM>/<NUM> is equivalent to upper portions of other head units discussed hereinabove.

<FIG> is a sectional illustration of a head unit <NUM>/<NUM>, similar to the head unit of <FIG>, and arranged about a longitudinal axis <NUM>/<NUM>. The head unit <NUM>/<NUM> is adapted for connection of a membrane <NUM>/<NUM> to the head by a clamping, or tightening ring <NUM>/<NUM>, as is known in the art of mechanical engineering. The membrane includes a central protrusions <NUM>/<NUM> and a circumferential protrusion <NUM>/<NUM>, where the central protrusion is higher than the circumferential protrusion. The head unit is presented with the membrane <NUM>/<NUM> at rest state.

<FIG> is a sectional illustration of the head unit <NUM>/<NUM> of <FIG>, following application thereto of a force in a direction indicated by arrow <NUM>/<NUM>, against an external surface <NUM>/<NUM>. As seen, the protrusions <NUM>/<NUM> and <NUM>/<NUM> all engage the external surface <NUM>/<NUM>, such that in the pressed state, the protrusions have the same height. It is appreciated that due to the difference in heights between the protrusions <NUM>/<NUM> and <NUM>/<NUM>, the engagement between the protrusions and the external surface occurs at different times, such that the engagement is graded and discontinuous, as described hereinabove.

It will be appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination.

Claim 1:
A head unit (<NUM>/<NUM>, <NUM>/2A, <NUM>/<NUM>), connectable to an external device, the external device including an actuator (<NUM>/<NUM>) suitable for operating the head unit, the actuator being fully disposed within the external device, the head unit comprising:
a first portion arranged about a main longitudinal axis (<NUM>/2A) of said head unit, said first portion having a first rigidity, said first portion including a first connection region (<NUM>/2A) reversibly connectable to the external device;
a second portion having a second rigidity, smaller than said first rigidity, said second portion comprising a flexible and elastic membrane (<NUM>/2A, <NUM>/<NUM>), said membrane including:
a first protrusion (<NUM>/2A, <NUM>/<NUM>) extending outwardly from said membrane away from said first portion and including a first extreme point associated with a first virtual tangential plane (<NUM>/2A); and
a second protrusion (<NUM>/2A, <NUM>/<NUM>) extending outwardly from said membrane away from said first portion and including a second extreme point associated with a second virtual tangential plane (<NUM>/2A); and
an intermediate portion (<NUM>/2A, <NUM>/<NUM>), fixedly attached to said first portion and disposed between said first portion and said second portion, said intermediate portion having a third rigidity, different from said first rigidity and from said second rigidity,
wherein a perimeter of said membrane is attached to said intermediate portion along a perimeter of said intermediate portion,
wherein said head unit can be operated by the actuator of the external device in a periodic manner with at least one amplitude and at least one frequency,
wherein said first and second protrusions are adapted, during operation of said head unit, to engage and apply force to an external surface (<NUM>/<NUM>) in a graded manner,
characterized in that an interior volume (<NUM>/<NUM>) is formed between said first portion and said second portion, said interior volume being sealed to an environment surrounding the head unit, and
wherein, in a rest state of the head unit and during operation of the head unit, said interior volume is filled with a fluid (<NUM>/<NUM>).