SURGICAL TABLE INCLUDING CABLE TAKE-UP MECHANISM

A surgical table includes a base, a tabletop, first and second frameworks, a cable, and a cable take-up mechanism. The first and second frameworks are moveable relative to one another to move the tabletop relative to the base in a first direction and a second direction that is opposite the first direction. The cable has a first end, a second end that is opposite the first end, and an intermediate portion. The first and second ends are mounted to the respective first and second frameworks. The cable take-up mechanism includes a constant-force spring coupled to the intermediate portion of the cable to take up slack in the cable as the first and second frameworks move relative to one another to move the tabletop relative to the base.

FIELD OF INVENTION

This application relates generally to a surgical table, and more particularly to a surgical table including a cable take-up mechanism for taking up slack in a cable of the surgical table.

BACKGROUND

Surgical tables employ various cable take-up mechanisms to take up slack in cables when for example the tabletop of the surgical table is raised or lowered relative to the base of the surgical table. Examples of cable take-up mechanisms include in-line connection spring-loaded systems, coiled cords, energy chains, hydraulic powered systems, cables sliding in grooves, among others. The main shortcoming of current spring-loaded systems is the inability to provide a constant force or tension on the cable throughout the range of motion of the cable. The drawback to hydraulic cylinder powered systems is accommodating the size of the cylinder and the requirement for a fluid pump. The shortcoming of energy chains and sliding groove arrangements is that they usually require linear movement of one component relative to another, making them incompatible for surgical tables lacking volumes that can accommodate such movement.

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

SUMMARY OF INVENTION

The application relates to surgical tables that employ components that address one or more of the foregoing problems. According to one aspect of the invention, a cable take-up mechanism includes a constant-force spring that provides or aids in providing a constant or near constant tension in a cable that would otherwise experience slack between two moving frameworks of the surgical table. In another aspect of the invention, a surgical table may include a sheave that enables up to twice as much variation in cable length, that is, up to two times as much slack may be taken-up than if no sheave was used. In yet another aspect, a surgical table may include a curved guide segment that enables the cable to travel along a changing cable travel path in two different directions, for example parallel to a longitudinal direction of a tabletop to a direction that is inclined relative to the longitudinal direction as the tabletop moves relative to a base of the surgical table. The surgical table may include any one or more of the foregoing features to reduce cable slack and/or maintain a tension in the cable, to reduce the volumetric footprint of the cable take-up mechanism particularly where the cable must be fed to components within the structure of the tabletop and/or supporting table framework, and/or to enable the cable to change travel paths for example to utilize space in other volumes of the surgical table.

According to one aspect of the invention, a surgical table includes a base; a tabletop; a first framework and a second framework moveable relative to one another to move the tabletop relative to the base in a first direction and a second direction that is opposite the first direction; a cable having a first end, a second end that is opposite the first end, and an intermediate portion, the first and second ends being mounted to the respective first and second frameworks; and a cable take-up mechanism including a constant-force spring coupled to the intermediate portion of the cable to take up slack in the cable as the first and second frameworks move relative to one another to move the tabletop relative to the base.

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

The constant-force spring may have a first end portion and a second end portion that is opposite the first end portion, the first end portion being mounted to the second framework to form a coupled spring-second framework connection, the second end portion being coupled to the intermediate portion of the cable for movement together as a coupled spring-cable connection.

The constant-force spring may be configured to extend the coupled spring-cable connection relative to the coupled spring-second framework connection as the tabletop moves in the first direction relative to the base, and to retract the coupled spring-cable connection relative to the coupled spring-second framework connection as the tabletop moves in the second direction relative to the base.

The first framework may include an upper column element of a column including upper and lower telescoping column elements, and the tabletop may be connected to the second framework, and the first end of the cable may be mounted to the upper column element at a cable-first framework connection, and the tabletop together with the second framework may be moveable relative to the cable-first framework connection as the first and second frameworks move relative to one another.

The second framework may include a trend frame and a tilt frame, and the tabletop may be connected to the tilt frame, and the tilt frame together with the tabletop connected thereto may be pivotably movable about a tilt axis that extends through the trend frame and the tilt frame.

The first direction and the second direction that the tabletop moves relative to the base may be respectively a vertically upward direction and a vertically downward direction.

At least one electrical actuator may be provided for moving the first framework and the second framework relative to one another.

The constant-force spring may be configured to maintain a constant tension in the cable as the tabletop moves relative to the base in the first and second directions.

The tabletop may be connected to the second framework, and the constant-force spring may be coupled to the intermediate portion of the cable to form a coupled spring-cable connection that is arranged for movement within the outermost dimensions of the tabletop and/or the second framework.

The cable take-up mechanism may include a sheave rotatably coupled to the constant-force spring, and wherein the cable slidably wraps around the sheave.

The cable may slidably wrap around the sheave in the range of 5 to 180 degrees.

The tabletop may be connected to the second framework, and the sheave may be arranged for movement within the outermost dimensions of the tabletop and/or the second framework as the tabletop moves relative to the base in the first and second directions.

The constant-force spring may have a first end portion and a second end portion that is opposite the first end portion, the first end portion being mounted to the second framework to form a coupled spring-second framework connection, the second end portion being coupled to the intermediate portion of the cable for movement together as a coupled spring-cable connection.

The constant-force spring may be configured to extend the sheave relative to the coupled spring-second framework connection as the tabletop moves in the first direction relative to the base, and to retract the sheave relative to the coupled spring-second framework connection as the tabletop moves in the second direction relative to the base.

The cable take-up mechanism may include a channeled frame mounted to the second framework and a bearing block constrained to sliding linear movement via a linear channel of the channeled frame, and the constant-force spring may be coupled to the intermediate portion of the cable by the bearing block.

The tabletop may be connected to the second framework, and the bearing block may be arranged for movement within the outermost dimensions of the tabletop and/or the second framework as the tabletop moves relative to the base in the first and second directions.

The cable take-up mechanism may include a sheave rotatably mounted to the bearing block, and the coupled spring-cable connection may include the cable slidably wrapping around the sheave.

The tabletop may be connected to the second framework, and the bearing block with the sheave rotatably mounted thereto may be arranged for movement within the outermost dimensions of the tabletop and/or the second framework as the tabletop moves relative to the base in the first and second directions.

The bearing block may slide along a translation axis that is parallel to a longitudinal direction of the tabletop.

The constant-force spring may have a first end portion and a second end portion that is opposite the first end portion, the first end portion being mounted to the second framework to form a coupled spring-second framework connection, the second end portion being coupled to the intermediate portion of the cable for movement together as a coupled spring-cable connection.

The constant-force spring may be configured to extend the bearing block relative to the coupled spring-second framework connection as the tabletop moves in the first direction relative to the base, and to retract the bearing block relative to the coupled spring-second framework connection as the tabletop moves in the second direction relative to the base.

A first end portion of the constant-force spring may include a coil portion and a second end portion of the constant-force spring may include a free end, and the coil portion may be fitted on a spool rotatably mounted to the second framework to form a coupled spring-second framework connection and the free end may be coupled to the intermediate portion of the cable for movement together as a coupled spring-cable connection.

The coil portion may be configured to uncoil to extend the coupled spring-cable connection relative to the coupled spring-second framework connection as the tabletop moves in the first direction relative to the base, and to coil to retract the coupled spring-cable connection relative to the coupled spring-second framework connection as the tabletop moves in the second direction relative to the base.

The tabletop may be connected to the second framework, and the cable take-up mechanism may include a curved guide segment around which the cable bends to change a travel path direction of the cable as the tabletop moves in the first and second directions relative to the base.

The curved guide segment may be configured to change the travel path direction from parallel to a longitudinal direction of the tabletop to a direction that is inclined relative to the longitudinal direction as the tabletop moves in the first and second directions relative to the base.

The tabletop may be connected to the second framework, and the second framework may be configured to pivot about a tilt axis extending in a longitudinal direction of the tabletop and at least a portion of the cable extends downward through an opening in the second framework to the first framework along a cable travel axis that is transverse to the tilt axis and offset from the tilt axis.

The tabletop may be connected to the second framework, and the second framework may be configured to pivot about a trend axis extending transverse to a longitudinal direction of the tabletop and at least a portion of the cable may extend downward through an opening in the second framework to the first framework along a cable travel axis that is transverse to the trend axis and offset from the trend axis.

According to another aspect of the invention, a surgical table includes a base; a tabletop; a first framework and a second framework moveable relative to one another to move the tabletop relative to the base in a first direction and a second direction that is opposite the first direction; a cable having a first end, a second end that is opposite the first end, and an intermediate portion, the first and second ends being mounted to the respective first and second frameworks; and, a cable take-up mechanism including a spring coupled to the intermediate portion of the cable to take up slack in the cable as the first and second frameworks move relative to one another to move the tabletop relative to the base; wherein the cable take-up mechanism includes a sheave rotatably coupled to the spring, and wherein the cable slidably wraps around the sheave.

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

The cable may slidably wrap around the sheave in the range of 5 to 180 degrees.

The tabletop may be connected to the second framework, and the sheave may be arranged for movement within the outermost dimensions of the tabletop and/or the second framework as the tabletop moves relative to the base in the first and second directions.

The spring may have a first end portion and a second end portion that is opposite the first end portion, the first end portion being mounted to the second framework to form a coupled spring-second framework connection, the second end portion being coupled to the intermediate portion of the cable for movement together as a coupled spring-cable connection.

The spring may be configured to extend the sheave relative to the coupled spring-second framework connection as the tabletop moves in the first direction relative to the base, and to retract the sheave relative to the coupled spring-second framework connection as the tabletop moves in the second direction relative to the base.

The cable take-up mechanism may include a channeled frame mounted to the second framework and a bearing block constrained to sliding linear movement via a linear channel of the channeled frame, and the constant-force spring may be coupled to the intermediate portion of the cable by the bearing block.

The tabletop may be connected to the second framework, and the bearing block may be arranged for movement within the outermost dimensions of the tabletop and/or the second framework as the tabletop moves relative to the base in the first and second directions.

The cable take-up mechanism may include a sheave rotatably mounted to the bearing block, and the coupled spring-cable connection may include the cable slidably wrapping around the sheave.

The tabletop may be connected to the second framework, and the bearing block with the sheave rotatably mounted thereto may be arranged for movement within the outermost dimensions of the tabletop and/or the second framework as the tabletop moves relative to the base in the first and second directions.

The bearing block may slides along a translation axis that is parallel to a longitudinal direction of the tabletop.

The spring may have a first end portion and a second end portion that is opposite the first end portion, the first end portion being mounted to the second framework to form a coupled spring-second framework connection, the second end portion being coupled to the intermediate portion of the cable for movement together as a coupled spring-cable connection.

The spring may be configured to extend the bearing block relative to the coupled spring-second framework connection as the tabletop moves in the first direction relative to the base, and to retract the bearing block relative to the coupled spring-second framework connection as the tabletop moves in the second direction relative to the base.

The spring may include a tension spring, a compression spring, or a constant-force spring.

According to another aspect of the invention, a surgical table includes a base; a tabletop; a first framework and a second framework moveable relative to one another to move the tabletop relative to the base in a first direction and a second direction that is opposite the first direction; a cable having a first end, a second end that is opposite the first end, and an intermediate portion, the first and second ends being mounted to the respective first and second frameworks; and, a cable take-up mechanism including a spring coupled to the intermediate portion of the cable to take up slack in the cable as the first and second frameworks move relative to one another to move the tabletop relative to the base; wherein the tabletop is connected to the second framework, and the cable take-up mechanism includes a curved guide segment around which the cable bends to change a travel path direction of the cable as the tabletop moves in the first and second directions relative to the base.

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

The curved guide segment may be configured to change the travel path direction from parallel to a longitudinal direction of the tabletop to a direction that is inclined relative to the longitudinal direction as the tabletop moves in the first and second directions relative to the base.

The spring may include a tension spring, a compression spring, or a constant-force spring.

The cable may include one or more of wires, cables, hoses, and/or lines, and/or bundles or harnesses of wires, cables, hoses, and/or lines.

The cable may be configured to transmit one or more of power, ground, control signals, communication signals, and/or fluids.

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

DETAILED DESCRIPTION

FIGS.1-13show a surgical table10and a cable take-up mechanism20(FIGS.12and13) thereof in accordance with an embodiment of the invention. The surgical table10includes a base30, a tabletop40, a column framework50, and a table framework60moveable relative to one another to move the tabletop40relative to the base30in a first direction D1and a second direction D2that is opposite the first direction D1. The surgical table10further includes a cable70, shown for example inFIGS.10,14and16, for transmitting one or more of power, ground, control signals, communication signals, fluids, among other things. As used herein, “cable” includes wires, cables, hoses, and/or lines, and/or bundles or harnesses of wires, cables, hoses, and/or lines. Cables may be in the form of electrical cables and/or fiber optic cables. Hoses may be in the form of hydraulic and/or pneumatic hoses. In the illustrated embodiment, the cable70is in the form of a cable bundle that includes power, CAN communication, and earth ground wires from a trend/fallback PCB located in the base and/or column framework50to PCBs located in the table framework60and/or the tabletop40. Earth ground may be used for example to BOND the tabletop40to the base30and/or column framework50.

The cable70has a first end72, a second end74that is opposite the first end72, and an intermediate portion76. The first end72and the second end74are mounted respectively to the column framework50and the table framework60. The cable take-up mechanism20includes a constant-force spring90, shown for example inFIGS.12and13, coupled to the intermediate portion76of the cable70to take up slack in the cable70as the column framework50and the table framework60move relative to one another to move the tabletop40relative to the base30. As shown inFIGS.10-13, the surgical table10may also or alternately include a sheave120rotatably coupled to the spring90, where the cable70slidably wraps around the sheave120. The surgical table10may also or alternately include a curved guide segment130around which the cable70bends to change the direction of the cable70as the tabletop40moves in the first and second directions D1, D2relative to the base30.

As will be described in greater detail below, several advantages may be realized by the components of the surgical table10in accordance with the invention. For example, the cable take-up mechanism20by means of the constant-force spring90may provide or aid in providing a constant tension in the cable70that would otherwise experience slack between first and second frameworks of a surgical table, such as the column framework50and the table framework60of the illustrated surgical table10. In some embodiments, the sheave120may enable up to twice as much variation in cable length, that is, up to two times as much slack may be taken-up than if no sheave120was used. The curved guide segment130may enable the cable70to travel along a changing cable travel path in two different directions, for example parallel to a longitudinal direction of the tabletop40to a direction that is inclined relative to the longitudinal direction as the tabletop40moves in the first and second directions D1, D2relative to the base30. The surgical table10in accordance with embodiments of the invention may include any one or more of the foregoing features to reduce cable slack and/or maintain a tension in the cable, to reduce the volumetric footprint of the cable take-up mechanism20particularly where the cable70must be fed to components within the structure of the tabletop40and/or the table framework60, and/or to enable the cable70to change travel paths for example to utilize space in other volumes of the surgical table10.

Turning initially then toFIG.1, the surgical table10includes the base30, a column140of adjustable height that is mounted on and extends from the base30, and the tabletop40. The tabletop40provides a patient support surface42. The surgical table10may include a mechanism for inclining the tabletop40relative to the column140by inclining the tabletop40about transverse and longitudinal horizontal axes of the tabletop40. Inclination about the transverse horizontal axis of the tabletop40is referred to in the art as “trending”, while inclination about the longitudinal horizontal axis of the tabletop40is referred to as “tilting”. In the illustrated surgical table10, compound movements also are possible, in which the tabletop40is inclined about both the transverse and longitudinal axes of the tabletop40at the same time. As used herein, the longitudinal axis of the tabletop40is the major axis of the tabletop40and the transverse axis of the tabletop40is the orthogonal minor axis of the tabletop40. The longitudinal direction of the tabletop40is parallel to the major axis and the transverse direction of the tabletop40is parallel to the minor axis. That is, the transverse direction of the tabletop40is perpendicular to, or orthogonal to, the longitudinal direction of tabletop40. Thus, inFIG.1, the longitudinal axis is left-right across the page and the transverse axis is into and out of the page.

The tabletop40includes five sections, namely a head section150, an upper torso section152, a lower torso section154and a pair of laterally adjacent leg sections156. The lower torso section154is coupled to the column140. As shown inFIG.3, the column140includes a plurality of column elements142,144,146which form a telescoping assembly; namely an upper or outer column element142, an intermediate column element144, and a lower or inner column element146. The telescoping assembly surrounds an electrical actuator160, which is shown schematically and in phantom inFIG.6, for raising and lowering the column140and thus the tabletop40relative to the base30in the first and second directions D1, D2. The electrical actuator160includes a column drive mechanism located within the inner column element146of the plurality of column elements142,144,146.

The electrical actuator160is coupled between the outer column element142and the base30and drives the outer column element142upwardly and downwardly relative to the base30, with the plurality of column elements142,144,146being coupled together so as to be raised or lowered in synchronism. As shown inFIG.5, the electrical actuator160has an upper end162coupled to a drive surface164affixed to the outer column element142of the plurality of column elements, and the drive surface164is provided by a plate166located inwardly of, and affixed to, the outer column element142. As shown inFIGS.5and6, the column140may include a plurality of linear motion guide units168, for example recirculating ball-type linear guides, between each pair of adjacent column elements142,144,146to aid in the telescoping movement.

With reference toFIGS.3-9, a first actuator mechanism170is coupled to the trend frame180and arranged to raise and lower the trend frame180relative to the column140and to rotate the trend frame180about a trend axis T-T extending in a transverse direction across the tabletop40, such raising and lowering, and/or such rotating, resulting in moving the tabletop40relative to the base30in the first and second directions D1, D2. The first actuator mechanism170is external of the column140. The first actuator mechanism170includes first and second electrical actuators172,174. The first actuator172is connected to a first portion190at one end of the trend frame180and the second actuator174is connected to a second portion192located at an opposite end of the trend frame180. The first and second portions190,192are mutually spaced and located on opposite sides of the trend axis T-T and on opposite sides of a tilt axis X-X extending in a longitudinal direction of the tabletop. The trend frame180is substantially rectangular and the first and second portions190,192are located at diagonally opposite corners of the trend frame180, as shown inFIG.5.

The first and second actuators172,174are coupled between the column140and the trend frame180for causing movement of the trend frame180relative to the column140. The first actuator172has an upper first end200connected to the first portion190of the trend frame180, and a lower second end202coupled to the column140. The second actuator174has an upper first end204connected to the second portion192of the trend frame180and a lower second end206coupled to the column140. The second end202,206of each of the first and second actuators172,174is coupled to an external surface220of the column140. The first and second actuators172,174each include an electric motor230, which includes an elongate element232, for example a leadscrew232, having an upper end240connected by a pivot joint242to the trend frame180and a drive assembly250adapted to rotate the leadscrew232to extend, or retract, the leadscrew232, so as respectively to raise, or lower, the respective first and second portions190,192of the trend frame180.

The drive assembly250of each first and second actuator172,174is pivotally connected to the trend frame180by a pivot mount252. Therefore, each of the first and second actuators172,174, including a respective electric motor230, elongate element232, and drive assembly250, and a respective one of first and second stabilizers262,264, is rotatable about the respective pivot mount252. The first and second actuators172,174can be operated independently so as to be driven in the same or opposite directions. Therefore, the rotational orientation of the first and second actuators172,174about the respective pivot mount252can be different.

A pair of fixed linear guide elements270, for example elongate channels, may be fixed to a portion of the column140such as the outer column element142, to guide respectively a pair of movable linear guide elements272, such as sliders, where the movable linear guide elements272are coupled to the trend frame180at respective trend pivots274, thereby ensuring the trend pivots274move vertically, that is, up and down inFIGS.3and4. A brace mechanism276, C-shape in top plan view, may be coupled to, and mounted between, the movable linear guide elements272. The free ends of the brace mechanism276may be rigidly affixed, for example by bolts or screws, to the respective movable linear guide members272, and thereby coupled to the trend frame180. The brace mechanism276aids in preventing twisting of the trend pivots274and the associated linear guide elements270,272.

As shown inFIGS.7-9, a tilt frame280of the surgical table10is mounted between the trend frame180and the tabletop40and is rotatable about the tilt axis X-X, such rotating resulting in moving the tabletop40relative to the base30in the first and second directions D1, D2. The tabletop40may be mounted to the tilt frame280in any suitable manner, for example by not shown bolts or screws. In the illustrated surgical table10, the tilt frame280surrounds the trend frame180, and the tilt axis X-X is above the trend axis T-T. A pivotable connection282is oriented along the tilt axis X-X and interconnects the trend frame180and the tilt frame280. An actuator290in the form of a rack and pinion mechanism290includes a curved rack292fitted to the trend frame180, a rotatable pinion gear294fitted to the tilt frame280, and an electrical drive motor296connected to the pinion gear294for rotating the pinion gear294. Rotation of the pinion gear294, in turn, causes the tilt frame280and the tabletop40mounted thereto to pivot about the tilt axis X-X, for example, between two opposite end positions relative to a central level position, as shown inFIGS.8and9.

As will be appreciated, the tabletop40may be moved relative to the base30in the first and second directions D1, D2in any number of ways, for example by vertical displacement by means of the actuator160and/or the first and second actuators172,174, as shown for example inFIGS.3,4and14-17, or by rotation about the trend axis T-T by means of the first and second actuators172,174, as shown for example inFIG.21, or by rotation about the tilt axis X-X by means of the actuator290, for example as shown inFIG.20, or by a combination of any of the foregoing. Of course, the invention is not limited to the illustrated surgical table10and other embodiments are contemplated. Thus, the surgical table10may employ other means to realize movement of the tabletop40relative to the base30in the first and second directions D1, D2, whether a different mechanism for vertically raising and lowering the tabletop40relative to the base30and/or a different mechanism for rotating the tabletop40about a trend axis, and/or a different mechanism for rotating the tabletop40about a tilt axis.

Next, a configuration of the cable take-up mechanism20in accordance with an embodiment of the invention is described with reference toFIGS.10-19. In the illustrated surgical table10, the afore described upper column element142forms the column framework50and the afore described trend frame180and tilt frame280form the table framework60. Other embodiments are contemplated. For example, the intermediate column element144or the lower column element146may form the column framework50. In one form, the column framework50may be a column without multiple column elements and/or telescoping capabilities.

The table framework60may rotate relative to a horizontal axis, either longitudinal or transverse, of the column140to move the tabletop40relative to the base30in the first and second directions D1, D2. In this regard, the surgical table may include a first table framework, for example the trend frame180, and a second table framework, for example the tilt frame280, in which case the first and second ends72,74of the cable70may be mounted to the respective first and second table frameworks180,280, and the constant-force spring90may be coupled to the intermediate portion76of the cable70to take up slack in the cable70as the first and second table frameworks180,280move relative to one another to move the tabletop40relative to the base30in the first and second directions D1, D2.

Further, the table framework60may include any type of table supporting framework, whether with trending and/or tilting capabilities, or without trending and/or tilting capabilities. In this regard, the surgical table10may include a first column framework, for example the upper column element142, and a second column framework, for example the lower column element146, in which case the first and second ends72,74of the cable70may be mounted to such respective first and second column frameworks142,146, and the constant-force spring90may be coupled to the intermediate portion76of the cable70to take up slack in the cable70as the first and second column frameworks142,146move relative to one another to move the tabletop40relative to the base30in the first and second directions D1, D2.

Referring toFIG.13, the constant-force spring90may include a constant-force leaf spring, a constant-force flat spring, a constant-force plate spring, a spiral wound torsion spring, a wound steel strip spring, a fluid dampening spring, a hydraulic spring, an electro-mechanical spring, a computer controlled spring, a computer controlled brake, or any other suitable constant-force spring type that exerts a constant or near constant force over its range of motion. The constant-force spring90has a first end portion302and a second end portion304that is opposite the first end portion302. The first end portion302may be mounted to the table framework60, for example the tilt frame280thereof, to form a coupled spring-second framework connection310. As shown inFIGS.13-19and described in greater detail below, the first end portion304may be coupled to the table framework60by a spool330rotatably mounted to the table framework60. The second end portion304of the constant-force spring90may be coupled to the intermediate portion76of the cable70for movement together as a coupled spring-cable connection320. As shown inFIG.10and described in greater detail below, the second end portion304may be coupled to the intermediate portion76of the cable70directly, or by one or more of the sheave120and/or a bearing block340.

FIGS.14,15and18show the first and second actuators172,174having moved the table framework60to a vertically lower position relative to the column framework50, thereby having moved the tabletop40relative to the base30in the second direction D2, that is downward inFIG.1.FIGS.16,17and19show the first and second actuators172,174having moved the table framework60to a vertically upper position relative to the column framework50, thereby having moved the tabletop40relative to the base30in the first direction D1, that is upward inFIG.1. Thus, referring to the movement from the view inFIG.18to the view inFIG.19, as the first and second actuators172,174move the table framework60from the vertically lower position to the vertically upper position to move the tabletop40relative to the base30in the first direction D1, that is upward inFIG.1, the constant-force spring90extends the coupled spring-cable connection320relative to the coupled spring-second framework connection310. Such extending reduces cable slack and/or maintains a constant or near constant tension in the cable70. Similarly, referring to the movement from the view inFIG.19to the view inFIG.18, as the first and second actuators172,174move the table framework60from the vertically upper position to the vertically lower position to move the tabletop40relative to the base30in the second direction D2, that is downward inFIG.1, the constant-force spring90retracts the coupled spring-cable connection320relative to the coupled spring-second framework connection310. Such retracting reduces cable slack and/or maintains a constant or near constant tension in the cable70.

The first and second ends72,74of the cable70may be mounted to the respective column framework50and table framework60at, respectively, a cable-first framework connection350and a cable-second framework connection352. As shown inFIGS.14,16and21, the first end72may be connected to the upper column element142by a bracket354attached to the upper column element142by not shown bolts or screws, thus forming the cable-first framework connection350. As described above, the tabletop40is mounted to the tilt frame280of the table framework60. The tabletop40together with the table framework60mounted thereto is moveable relative to the cable-first framework connection350as the column framework50and the table framework60move relative to one another to move the tabletop40relative to the base30in the first and second directions D1, D2. As shown inFIGS.10,19and22, the second end74of the cable70may be connected to the table framework60by a bracket or zip tie356attached to the table framework60, thus forming the cable-second framework connection352.

Referring now toFIGS.1,10and11, the cable take-up mechanism20is arranged within a space or volume bound at its bottom by a lower wall360of the table framework60, at its sides by four upright walls362,364,366,368of the table framework60, and at its top by the structure of the tabletop40that is mounted on the table framework60, as shown inFIG.1. As such, the coupled spring-cable connection320of the cable take-up mechanism20is arranged for movement within the outermost dimensions of the tabletop40and the table framework60as the tabletop40moves relative to the base30in the first and second directions D1, D2. In some embodiments, the cable take-up mechanism20may be arranged entirely within the outermost dimensions of the table framework60, for example where sufficient depth is provided by the upright walls362,364,366,368, or arranged entirely within the outermost dimensions of the tabletop40, for example where sufficient depth is provided within the structure of the tabletop40. As will be appreciated, the relatively small volumetric footprint of the cable take-up mechanism enables the cable take-up mechanism20to be arranged in spaces or volumes of the surgical table10that heretofore could not accommodate a cable take-up mechanism, for example, a hydraulic cylinder powered take-up mechanism.

In some embodiments, the coupled spring-cable connection320may be arranged for movement not only within the outermost dimensions of the tabletop40and the table framework60but also arranged for movement within the space below the table framework60, for example alongside the column140, particularly where the coupled spring-cable connection320may be configured to bend around the curved guide segment130to below the table framework60.

In the illustrated cable take-up mechanism20, the second end portion304of the constant-force spring90is coupled to the intermediate portion76of the cable70to form the coupled spring-cable connection320by means of the afore mentioned sheave120. InFIG.13, the sheave120is rotatably coupled to the second end portion304by the bearing block340. Following, then, is a description of an exemplary configuration of the coupling including the sheave120, the bearing block340, and the second end portion304of the constant-force spring90, in accordance with an embodiment of the invention.

The bearing block340includes a horizontal threaded hole380. The distal end of the second end portion304of the constant-force spring90includes a corresponding through hole382. The distal end of the second end portion304is abutted against a side wall384of the bearing block340to align the through hole382with the horizontal threaded hole380in the bearing block340. A threaded bolt390may then be threaded into the threaded hole380to connect the second end portion304of the constant-force spring90to the bearing block340. The bearing block340also includes a vertical threaded hole400. The vertical threaded hole400is offset from the horizontal threaded hole380so as not to overlap one another. The sheave120includes a hub410and a pair of side walls412on opposite sides of the hub410. The hub410and side walls412have central openings that together form a corresponding bore414in the sheave120when the hub410and side walls412are assembled in side-by-side fashion. The bore414of the sheave120has a diameter that is slightly larger than the diameter of the shank, or shoulder, of a shoulder bolt420to be passed therethrough. The sheave120is abutted against a top wall424of the bearing block340to align the bore414with the vertical threaded hole400. The shoulder bolt420may then be passed through the bore414and threaded into the vertical threaded hole400to rotatably connect the sheave120to the bearing block340.

As shown inFIG.10, the intermediate portion76of the cable70may be slidably wrapped around the sheave120. As the constant-force spring90, with the bearing block340connected to the second end portion304thereof, extends and retracts to take up slack and maintain a constant or near constant tension in the cable70, the intermediate portion76of the cable70slidably wraps around the sheave120, entering one side thereof and exiting another side thereof, in the illustrated embodiment wrapping around the sheave120approximately 180 degrees. Thus, the constant-force spring90may be configured to extend the sheave120relative to the coupled spring-second framework connection310as the tabletop40moves in the first direction D1relative to the base30, as shown for example inFIG.16. Such extending reduces cable slack and/or maintains a constant or near constant tension in the cable70. Further the constant-force spring90may be configured to retract the sheave120relative to the coupled spring-second framework connection310as the tabletop40moves in the second direction D2relative to the base30, as shown for example inFIG.14. Such retracting reduces cable slack and/or maintains a constant or near constant tension in the cable70. The cable70may slidably wrap around the sheave120either by slippage between the surface of the cable70and the surface of the sheave120, or by the bore414slidably bearing against the shoulder bolt420, or by a combination of the foregoing. Also, the cable70may wrap around the sheave120in other angular amounts, for example 90 degrees or anywhere in the range of five (5) to 180 degrees.

As will be appreciated, by wrapping the cable70around the sheave120about 180 degrees the sheave120enables twice as much variation in cable length. Thus, the cable take-up mechanism20by means of the sheave120can take up two times as much slack in the cable70than if no sheave120was used, which translates into larger movements of the tabletop40relative to the base30in the first and second directions D1, D2. This is illustrated by a comparison ofFIG.16andFIG.14. InFIG.16, the tabletop40has been moved vertically upward relative to the base30, resulting in the length of the cable70between the cable-first framework connection350and the tabletop40being about 20 inches. InFIG.14, the tabletop has been moved vertically downward relative to the base30, resulting in the length of the cable70between the cable-first framework connection350and the tabletop40being about 10 inches. Thus, the cable take-up mechanism20takes up about ten (10) inches of slack in the cable70as the tabletop40is moved relative to the base30from the position shown inFIG.16to the position shown inFIG.14. However, as shown in the upper portions ofFIGS.14and16, the length of travel of the sheave120and the second end portion304of the constant-force spring90to which the sheave120is rotatably mounted, is only about five (5) inches, that is, half the length of cable70taken up by the constant-force spring90.

In some embodiments, the length of cable70required to be taken up by the cable take-up mechanism20may not require such two-to-one take-up ratio. For example, the amount of wrap around the sheave120may be less than 180 degrees, in which case the corresponding ratio of length of slack taken up relative to length of movement of the sheave120will be less than two-to-one.

In other embodiments, the sheave120may be omitted, in which case the intermediate portion76of the cable70may be coupled by other means to the second end portion304of the constant-force spring90to form the coupled spring-cable connection320. For example, the intermediate portion76of the cable70may be directly connected to the second end portion304, as shown for example inFIG.22. In one form, the intermediate portion76of the cable70may be passed through the through hole382in the distal end of the second end portion304of the constant-force spring90in such a manner that the intermediate portion76and the distal end move together as a unit. The through hole382, or any other part of the distal end of the second end portion304, may be configured to accommodate a gripping sleeve430that grips the cable70as shown inFIG.22for such purpose. In another form, the bearing block340may be configured to accommodate a bracket that secures the intermediate portion76to the bearing block340in such a manner that the intermediate portion76, the bracket, the bearing block340and the distal end of the second end portion304move together as a unit.

Referring again toFIGS.1,10and11, the cable take-up mechanism20including the sheave120may be arranged within a space or volume bound at its bottom by the lower wall360, at its sides by the four upright walls362,364,366,368, and at its top by the structure of the tabletop40. As such, the sheave120of the cable take-up mechanism20is arranged for movement within the outermost dimensions of the tabletop40and the table framework60as the tabletop40moves relative to the base30in the first and second directions D1, D2. The relatively small volumetric footprint of the cable take-up mechanism20, even including the sheave120, enables the cable take-up mechanism20to be arranged in spaces or volumes of the surgical table10that heretofore could not accommodate a cable take-up mechanism, for example, a hydraulic cylinder powered take-up mechanism.

As shown inFIGS.10-13and18-20, the illustrated cable take-up mechanism may include a channeled frame440mounted to the table framework60. The channeled frame440constrains the bearing block340, and thus the constant-force spring90mounted thereto, to sliding linear movement via a linear channel442of the channeled frame440. As previously described, the second end portion304of the constant-force spring90may be coupled to the intermediate portion76of the cable70by the bearing block340to form the coupled spring-cable connection320, whether by the intermediate portion76wrapping around the sheave120rotatably coupled to the bearing block340or by a bracket that secures the intermediate portion76to the bearing block340in such a manner that the intermediate portion76, the bracket, the bearing block340and the distal end of the second end portion304move together as a unit. Thus, the constant-force spring90may be configured to extend the bearing block340and the coupled spring-cable connection320relative to the coupled spring-second framework connection310as the tabletop40moves in the first direction D1relative to the base30, as shown for example inFIG.16. Such extending reduces cable slack and/or maintains a constant or near constant tension in the cable70. Further, the constant-force spring90may be configured to retract the bearing block340and the coupled spring-cable connection320relative to the coupled spring-second framework connection310as the tabletop moves in the second direction D2relative to the base30, as shown for example inFIG.14. Such retracting reduces cable slack and/or maintains a constant or near constant tension in the cable70.

FIG.13shows a configuration of the channeled frame440in accordance with an embodiment of the invention. The channeled frame440includes a base450and a pair of guide plates452,454. The base450is mounted to the table framework60, for example by screws460threaded into not shown threaded openings in the lower wall360of the table framework60. The base450has two upright walls472,474that are oriented parallel to one another to define a lower linear slot or guideway478therebetween. The guide plates452,454are mounted to the upper surfaces of the respective upright walls472,474, for example by screws480threaded into corresponding threaded openings482in the upright walls472,474. The guide plates452,454are oriented parallel to one another to define an upper linear slot or guideway488therebetween. The inner portions of the guide plates452,454form a pair of parallel tracks492,494. The upper guideway488is less in width than the lower guideway478. The lower guideway478and the upper guideway488together provide the linear channel442that slidably receives the bearing block340.

The bearing block340has a lower bearing portion500, a middle bearing portion502, and an upper bearing portion504. The upper and lower bearing portions502,504are greater in width than the middle bearing portion502to define a pair of grooves522,524in opposite sides of the bearing block340. The grooves522,524of the bearing block340slidably engage the respective tracks492,494of the channeled frame440. Additionally, the lower bearing portion504with the second end portion304of the constant-force spring90mounted thereto may be slightly less in width than the lower guideway478of the channeled frame440such that the lower bearing portion504with the second end portion304mounted thereto slidably abuts inward facing surfaces532,534of the upright walls472,474that form the lower guideway478.

The channeled frame440ensures that the bearing block340and thus the coupled spring-cable connection320moves along a linear path and does not shift or sag within the table framework60and/or the tabletop40during raising and lowering and/or tilting and/or trending of the tabletop40. Thus, as the constant-force spring90takes up slack in the cable70as the table framework60and the column framework50move relative to one another to move the tabletop40relative to the base30in the first and second directions D1, D2, the bearing block340slidably engages the linear channel442along the linear path. In the illustrated embodiment, the linear channel442of the channeled frame440linearly guides movement of the bearing block340and thus the second end portion304of the constant-force spring90mounted thereto along a translation axis that is parallel to the longitudinal direction of the tabletop40. It will be appreciated that in some embodiments the channeled frame440may be oriented such that the linear channel442linearly guides the bearing block340along a translation axis that is parallel to the transverse direction of the tabletop40, or along a translation axis that is at an oblique angle relative to the longitudinal direction and transverse direction.

Referring again toFIGS.1,10and11, the cable take-up mechanism20including the bearing block340may be arranged within a space or volume bound at its bottom by the lower wall360, at its sides by the four upright walls362,364,366,368, and at its top by the structure of the tabletop40. As such, the bearing block340of the cable take-up mechanism20is arranged for movement within the outermost dimensions of the tabletop40and the table framework60as the tabletop moves relative to the base30in the first and second directions D1, D2. The relatively small volumetric footprint of the cable take-up mechanism20, even including the bearing block340, enables the cable take-up mechanism20to be arranged in spaces or volumes of the surgical table10that heretofore could not accommodate a cable take-up mechanism, for example, a hydraulic cylinder powered take-up mechanism.

In embodiments where a sheave120is rotatably mounted to the bearing block340, as shown inFIGS.1,10and11, the cable take-up mechanism20including the bearing block340and sheave120rotatably mounted thereto may be arranged within a space or volume bound at its bottom by the lower wall360, at its sides by the four upright walls362,364,366,368, and at its top by the structure of the tabletop40. As such, the bearing block340with the sheave120rotatably mounted thereto is arranged for movement within the outermost dimensions of the tabletop40and the table framework60as the tabletop40moves relative to the base30in the first and second directions D1, D2. Here too, the relatively small volumetric footprint of the cable take-up mechanism20, even including the bearing block340and the sheave120rotatably mounted thereto, enables the cable take-up mechanism20to be arranged in spaces or volumes of the surgical table10that heretofore could not accommodate a cable take-up mechanism, for example, a hydraulic cylinder powered take-up mechanism.

Referring again toFIG.13, a configuration of the coupled spring-second framework connection310will now be described. As previously described, the first end portion302of the constant-force spring90may be coupled to the table framework60to form the coupled spring-second framework connection310. In the illustrated embodiment, the first end portion302of the constant-force spring90may include a coil portion542and the second end portion304of the constant-force spring90may include a free end544. The coil portion542may be fitted on the afore mentioned spool330which, in turn, may be rotatably mounted to the table framework60to form the coupled spring-second framework connection310. The free end544may be coupled to the intermediate portion76of the cable70by any of the afore described means, that is directly or by one or more of the sheave120and/or the bearing block340, for movement of the free end544and the intermediate portion76together as the coupled spring-cable connection320.

The spool330may be rotatably mounted to the table framework60by a shoulder bolt560. As shown inFIG.13, the bore562of the spool330has a diameter that is slightly larger than the diameter of the shank, or shoulder, of the shoulder bolt560to be passed therethrough. The coil portion542, once installed on the spool330, is flanked on one side by a lower circumferential flange564of the spool330and on the opposite side by a washer566. The washer566has a through hole572that has a diameter slightly larger than the diameter of the shank, or shoulder, of the shoulder bolt560to be passed therethrough. The spool330, the coil portion542, and the washer566are stacked, in that order, and the shoulder bolt560is passed through the through hole572of the washer566and the bore562of the spool330and threaded into a not shown threaded opening in the lower wall360of the table framework60thereby rotatably mounting the spool330to the table framework60.

FIGS.14and16show an example of the constant-force spring90and particularly the coil portion542thereof in operation. As shown inFIG.16, as the tabletop40moves in the first direction D1relative to the base30the coil portion542uncoils, that is unwinds, to extend the coupled spring-cable connection320relative to the coupled spring-second framework connection310. Such extending reduces cable slack and/or maintains a constant or near constant tension in the cable70. As shown inFIG.14, as the tabletop40moves in the second direction D2relative to the base30, the coil portion542coils, that is winds up, to retract the coupled spring-cable connection320relative to the coupled spring-second framework connection310. Such retracting reduces cable slack and/or maintains a constant or near constant tension in the cable70.

In the illustrated embodiment, the first end portion302of the constant-force spring90is in the form of the coil portion542, which is coupled to the table framework60to form the coupled spring-second framework connection310, and the second end portion304of the constant-force spring90is in the form of the free end544, which is coupled to the intermediate portion76of the cable70for movement together as a coupled spring-cable connection320. Other embodiments are contemplated. For example, the coil and free end relationship may be switched. Thus, in some embodiments, the first end portion302of the constant-force spring90may be in the form of a free end that is coupled to the table framework60to form the coupled spring-second framework connection310, and the second end portion304of the constant-force spring90may be in the form of a coil spring that is coupled to the intermediate portion76of the cable70for movement together as a coupled spring-cable connection320.

Referring now toFIGS.10-19and21-24, the curved guide segment130in accordance with an embodiment of the invention will now be described. As will be appreciated, in some embodiments, the surgical table10may be configured without the curved guide segment130, for example where no change in a cable travel path direction of the cable70is required or a change in the travel path direction of the cable70is accomplished by other means.

As shown inFIG.13, the curved guide segment130may take the form of a quarter round or 90 degrees arc structure. The curved guide segment includes a 90 degree hub600and a pair of 90 degree rims or flanges602extending radially outward from the hub600on axially opposite sides of the hub600. The hub600and flanges602form first and second U-shape openings604,606at opposite ends of the arc, as shown for example inFIGS.18,19and22-24. As shown inFIG.19, the first and second U-shape openings604,606of the curved guide segment130may be sized to receive the cable70therethrough with a tolerance of approximately one-half cable diameter on opposite sides of the cable70. This allows the cable70to shift laterally as the cable70bends around the curved guide segment130.

The hub600includes an axial through hole620for receiving a screw622therethrough. A corresponding threaded hole624is provided in the upright wall472of the channeled frame440. The curved guide segment130is mounted in fixed relation to the table framework60by passing the screw622through the through hole620of the hub600and threading the screw622into the corresponding threaded hole624in the upright wall472of the channeled frame440. In an alternate form, the hub600may include a radially extending hole therein that protrudes in a vertical direction and the upright wall472may include a corresponding threaded hole that extends in a vertical direction, the vertical direction being up and down inFIG.13, so that the screw622may be inserted from a vertical direction, that is, from above inFIG.13, to secure the hub600to the upright wall472.

FIGS.14,16,18,19and21show the position of the curved guide segment130relative to the sheave120, the table framework60, and the column framework50. As shown inFIGS.18and19, the first U-shape opening604is configured to align with the sheave120and the second U-shape opening606is configured to align with an opening630in the lower wall360of the table framework60. In the illustrated embodiment, the opening630is positioned such that when the tabletop is in a horizontal position the opening630is offset from the trend axis T-T and offset from the tilt axis X-X. The cable70extends along a first cable travel axis J-J where the cable70is tangential to the outer diameter of the hub410of the sheave120and aligned with the center of the first U-shape opening604of the curved guide segment130. As shown inFIGS.14,16and21, the cable70also extends along a second cable travel axis K-K where the cable70is aligned with the center of the second U-shape opening604and is connected to the column framework50to form the cable-first framework connection350. In the illustrated embodiment, the portion of the cable70extending in the direction along the first cable travel axis J-J is parallel to the longitudinal direction of the tabletop40and the portion of the cable70extending in the direction along the second cable travel axis K-K is inclined relative to the longitudinal direction.

Referring toFIGS.14and16, the curved guide segment130changes the travel path direction of the cable70from parallel to the longitudinal direction of the tabletop40to an incline of about 80 degrees relative to the longitudinal direction as the tabletop40moves in the first and second directions D1, D2relative to the base30. InFIG.21, the curved guide segment130changes the travel path direction of the cable70from parallel to the longitudinal direction of the tabletop40to an incline of about 90 degrees, that is perpendicular, relative to the longitudinal direction as the tabletop40moves in the first and second directions D1, D2relative to the base30.

The cable70passes through the opening630in the lower wall360of the table framework60as the cable70transitions from the longitudinal direction travel path to the inclined direction travel path, and vice versa.FIGS.16and19show the table framework60raised to a vertically upper position, for example, by the actuators172,174. Owing to the offset position of the opening630in the lower wall360of the table framework60, the inclined direction travel path, that is, that portion of the cable70extending downward from the table framework60to the column framework50along the second cable travel axis K-K, is transverse to the tilt axis X-X and offset from the tilt axis X-X, and transverse to the trend axis T-T and offset from the trend axis T-T.FIG.20shows the tilt frame280of the table framework60pivoted about the tilt axis X-X, for example, by the actuator290. Here too, owing to the offset position of the opening630in the lower wall360of the table framework60, the inclined direction travel path is transverse to the tilt axis X-X and offset from the tilt axis X-X.FIG.21shows the trend frame180of the table framework60pivoted about the trend axis T-T, for example, by the actuators172,174. Here too, owing to the offset position of the opening630in the lower wall360of the table framework60, the inclined direction travel path is transverse to the trend axis T-T and offset from the trend axis T-T. In each of the foregoing movements of the table framework60relative to the column framework50, the offset of the opening630enables the cable70to travel unobstructed between the tabletop40or table framework60to the column framework50, and vice versa. This is advantageous in that the cable70may be directed to the outside of and/or alongside the column140of the surgical table10and away from the actuators172,174located at diagonally opposite corners of the column140and away from the moveable linear guide elements272, as shown inFIGS.14and16, thus allowing movement of the actuators172,174and moveable linear guide elements272.

As will be appreciated, the cable take-up mechanism20equipped with the curved guide segment130, in changing the travel path directions of the cable70, enables the cable70to utilize space in volumes of the surgical table10that heretofore were not available for prior cable take-up mechanisms, for example, cable take-up mechanisms employing cable chains or sliding groove arrangements. In the illustrated embodiment, the curved guide segment130enables the cable70to move along two different travel path directions, that is, two degrees of freedom. It will be appreciated that in some embodiments multiple curved guide segments130may be used to provide the cable70with three or more travel path directions, that is three or more degrees of freedom, wherein each travel path direction is within respective different spaces in different volumes of the surgical table10.

FIG.23shows a table framework60and cable take-up mechanism720in accordance with another embodiment of the invention. TheFIG.23cable take-up mechanism720is in many respects similar to the above-described cable take-up mechanism20, and consequently the same reference numerals are used to denote structures corresponding to similar structures in the cable take-up mechanism20. In addition, the foregoing description of the cable take-up mechanism20, including the sheave120, the curved guide segment130, the bearing block340, and the channeled frame440, is equally applicable to theFIG.23cable take-up mechanism720except as noted below. Moreover, it will be appreciated upon reading and understanding the specification that aspects of the cable take-up mechanisms20,720may be substituted for one another or used in conjunction with one another where applicable.

Turning then toFIG.23, the cable take-up mechanism720includes a tension spring790coupled to the intermediate portion76of the cable70to take up slack in the cable70as the table framework60and the cable framework50move relative to one another to move the tabletop40relative to the base30in the first and second directions D1, D2. The cable take-up mechanism720may include the sheave120rotatably coupled to the tension spring790such that the cable70slidably wraps around the sheave120. As will be appreciated, the coupling may be by means of a not-shown yoke, for example. In some embodiments, the sheave120may be omitted, in which case the intermediate portion76of the cable70may be coupled by other means to the second end portion304of the tension spring790to form the coupled spring-cable connection320. The cable take-up mechanism720may include the curved guide segment130around which the cable70may bend to change a travel path direction of the cable70as the tabletop40moves in the first and second directions D1, D2relative to the base30. In some embodiments, the surgical table10may be configured without the curved guide segment130, for example where no change in a cable travel path direction of the cable70is required or a change in the travel path direction of the cable70is accomplished by other means. Although not shown inFIG.23, it will be appreciated that the tension spring790may be coupled to the intermediate portion76of the cable70by the bearing block340. Further, the cable take-up mechanism720may include the channeled frame440to constrain the bearing block340to sliding linear movement via the linear channel of the channeled frame440, thus ensuring that the bearing block340and thus the tension spring790mounted thereto move along a linear path and do not shift or sag within the table framework60and/or the tabletop40during raising and lowering and/or tilting and/or trending of the tabletop40.

FIG.24shows a table framework60and cable take-up mechanism820in accordance with another embodiment of the invention. TheFIG.24cable take-up mechanism820is in many respects similar to the above-described cable take-up mechanisms20,720and consequently the same reference numerals are used to denote structures corresponding to similar structures in the cable take-up mechanisms20,720. In addition, the foregoing description of the cable take-up mechanisms20,720including the sheave120, the curved guide segment130, the bearing block340, and the channeled frame440, is equally applicable to theFIG.24cable take-up mechanism820except as noted below. Moreover, it will be appreciated upon reading and understanding the specification that aspects of the cable take-up mechanisms20,720,820may be substituted for one another or used in conjunction with one another where applicable.

Turning then toFIG.24, the cable take-up mechanism820includes a compression spring890coupled to the intermediate portion76of the cable70to take up slack in the cable70as the table framework60and the cable framework50move relative to one another to move the tabletop40relative to the base30in the first and second directions D1, D2. The cable take-up mechanism820may include the sheave120rotatably coupled to the compression spring890such that the cable70slidably wraps around the sheave120. As will be appreciated, the coupling may be by means of a not-shown yoke, for example. In some embodiments, the sheave120may be omitted, in which case the intermediate portion76of the cable70may be coupled by other means to the second end portion304of the compression spring890to form the coupled spring-cable connection320. The cable take-up mechanism820may include the curved guide segment130around which the cable70may bend to change a travel path direction of the cable70as the tabletop40moves in the first and second directions D1, D2relative to the base30. In some embodiments, the surgical table10may be configured without the curved guide segment130, for example where no change in a cable travel path direction of the cable70is required or a change in the travel path direction of the cable70is accomplished by other means. Although not shown inFIG.24, it will be appreciated that the compression spring890may be coupled to the intermediate portion76of the cable70by the bearing block340. Further, the cable take-up mechanism820may include the channeled frame440to constrain the bearing block340to sliding linear movement via the linear channel of the channeled frame440, thus ensuring that the bearing block340and thus the compression spring890mounted thereto move along a linear path and do not shift or sag within the table framework60and/or the tabletop40during raising and lowering and/or tilting and/or trending of the tabletop40.

As will be appreciated, in some embodiments, the cable take-up mechanism constrains the rotating sheave to a linear motion on a bearing block. In some embodiments, the cable may enter one side of the sheave and exit the other side after changing direction. In some embodiments, the cable take-up mechanism may include a constant-force spring to exert a constant force or near constant force on the bearing block which in turn maintains a constant tension on the cable. The cable take-up mechanism may allow a constant tension to be applied to the cable while retracting 10 inches of the cable's length. The design can be adjusted for shorter or longer lengths as needed. This prevents the cable from being stressed unnecessarily at the spring's extended condition. The constant tension, or near constant tension, may be accomplished in the constant-force spring coil acting on the sheave. In some embodiments, the constant-force spring could be replaced by a tension spring or compression spring or any other suitable spring as noted above, depending on the available volume and desired spring performance profile. The constant-force spring is a compact way to apply tension to the cable through a relatively large range of motion. The range of motion typically will be limited only by the space available for the diameter of the retracted constant-force spring coil, whereas prior systems were limited by the range of motion of a linear or torsion spring or a hydraulic cylinder. Application of the constant tension to the cable may be by using a combination of any one or more of the constant-force spring, the bearing block, the sheave, the channeled frame, and/or the curved guide segment. The surgical table may employ the constant-force spring as part of a cable tensioning system in multiple spaces in multiple volumes of the surgical table.