Cartesian Winch Spooler with Counterbalance

Abstract

A winch system includes a reel, a reel motor operably connected to the reel and configured to rotate the reel about a reel axis, and a spooling guide assembly. The spooling guide assembly includes a spooling guide supported by a carriage so as to be movable with the carriage along a Cartesian x-axis. A table on which the carriage is movably mounted is configured to be moved along a Cartesian y-axis which is perpendicular to the Cartesian x-axis. A frame is configured to support the table. A first counterbalance has a first portion fixedly attached to the frame. The first counterbalance is operably connected to the table and is configured to apply a first force to the table in a first direction opposite to a gravitational force on the table when the table is located at a first position.

Claims

1. A winch system, comprising: a reel; a reel motor operably connected to the reel and configured to rotate the reel about a reel axis; and a spooling guide assembly, the spooling guide assembly including a spooling guide supported by a carriage so as to be movable with the carriage along a Cartesian x-axis, a table on which the carriage is movably mounted, the table configured to be moved along a Cartesian y-axis, the Cartesian y-axis perpendicular to the Cartesian x-axis, a frame configured to support the table, and a first counterbalance having a first portion fixedly attached to the frame, the first counterbalance operably connected to the table and configured to apply a first force to the table in a first direction opposite to a gravitational force on the table when the table is located at a first position.

2. The winch system of claim 1, the spooling guide assembly further comprising: a table motor; and a first drive shaft operably coupled to the table motor and to the table so as to move the table along the Cartesian y-axis, wherein the first counterbalance has a second portion fixedly attached to the first drive shaft.

3. The winch system of claim 2, the spooling guide assembly further comprising: a second counterbalance with a third portion fixedly attached to the frame, the second counterbalance operably connected to the table and configured to apply a second force to the table in a second direction opposite to the first direction when the table is located at the first position.

4. The winch system of claim 3, the spooling guide assembly further comprising: a second drive shaft operably coupled to the table, wherein the second counterbalance includes a fourth portion fixedly attached to the second drive shaft.

5. The winch system of claim 4, the spooling guide assembly further comprising: a first drive wheel operably connected to the first drive shaft; a second drive wheel operably connected to the second drive shaft; and a drive component operably connected to the first drive wheel and the second drive wheel so as to drive the second drive wheel with the first drive wheel.

6. The winch system of claim 5, wherein: the first counterbalance is configured to apply a third force to the table when the table has been moved in the first direction from the first position to a second position; the second counterbalance is configured to apply a fourth force to the table when the table has been moved in the first direction from the first position to the second position; and either the third force is less than the first force and the fourth force is greater than second force, or the third force is greater than the first force and the fourth force is less than the second force.

7. The winch system of claim 6, wherein: the first counterbalance and the second counterbalance are configured to provide a floating condition for the table.

8. The winch system of claim 7, wherein: the reel includes a barrel section and at least one flange at an end of the barrel section; and the first counterbalance and the second counterbalance are configured to provide a floating condition for the table at a location midway between a height of the table when the spooling guide is aligned with a top of the barrel section, and a height of the table when the spooling guide is aligned with a top course of flexible material when a maximum number of courses of the flexible material are spooled on the reel.

9. The winch system of claim 8, wherein: the first counterbalance and the second counterbalance are configured to provide the floating condition for the table at a location whereat the spooling guide is aligned at one-half a height of the at least one flange above the top of the barrel section.

10. The winch system of claim 6, wherein: the first counterbalance comprises one of a first torsion spring, a first pneumatic cylinder, and a first hydraulic cylinder; and the second counterbalance comprises one of a second torsion spring, a second pneumatic cylinder, and a second hydraulic cylinder.

11. A spooling guide assembly, comprising: a spooling guide supported by a carriage so as to be movable with the carriage along a Cartesian x-axis to align the spooling guide with a spooling location of a reel; a table on which the carriage is movably mounted, the table configured to be moved along a Cartesian y-axis, the Cartesian y-axis perpendicular to the Cartesian x-axis; a frame configured to support the table; and a first counterbalance having a first portion fixedly attached to the frame, the first counterbalance operably connected to the table and configured to apply a first force to the table in a first direction opposite to a gravitational force on the table when the table is located at a first position.

12. The spooling guide assembly of claim 11, further comprising: a table motor; and a first drive shaft operably coupled to the table motor and to the table so as to move the table along the Cartesian y-axis, wherein the first counterbalance has a second portion fixedly attached to the first drive shaft.

13. The spooling guide assembly of claim 12, further comprising: a second counterbalance with a third portion fixedly attached to the frame and operably connected to the table, the counterbalance configured to apply a second force to the table in a second direction opposite to the first direction when the table is located at the first position.

14. The spooling guide assembly of claim 13, further comprising: a second drive shaft operably coupled to the table, wherein the second counterbalance has a fourth portion fixedly attached to the second drive shaft.

15. The spooling guide assembly of claim 14, further comprising: a first drive wheel operably connected to the first drive shaft; a second drive wheel operably connected to the second drive shaft; and a drive component operably connected to the first drive wheel and the second drive wheel so as to drive the second drive wheel with the first drive wheel.

16. The winch system of claim 12, wherein: the first counterbalance is configured to apply a third force to the table when the table has been moved in the first direction from the first position to a second position; the second counterbalance is configured to apply a fourth force to the table when the table has been moved in the first direction from the first position to the second position; and either the third force is less than the first force and the fourth force is greater than second force, or the third force is greater than the first force and the fourth force is less than the second force.

17. The spooling guide assembly claim 16, wherein: the first counterbalance and the second counterbalance are configured to provide a floating condition for the table.

18. The spooling guide assembly of claim 17, wherein: the reel includes a barrel section and at least one flange at an end of the barrel section; and the first counterbalance and the second counterbalance are configured to provide a floating condition for the table at a location midway between a height of the table when the spooling guide is aligned with a top of a barrel section of the reel, and a height of the table when the spooling guide is aligned with a top course of flexible material when a maximum number of courses of the flexible material are spooled on the reel.

19. The spooling guide assembly of claim 18, wherein: the first counterbalance and the second counterbalance are configured to provide the floating condition for the table at a location whereat the spooling guide is aligned at one-half a height of at least one flange of the reel above the top of the barrel section.

20. The spooling guide assembly of claim 19, wherein: the first counterbalance comprises one of a first torsion spring, a first pneumatic cylinder, and a first hydraulic cylinder; and the second counterbalance comprises one of a second torsion spring, a second pneumatic cylinder, and a second hydraulic cylinder.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above-described features and advantages, as well as others, will become more readily apparent to those of ordinary skill in the art by reference to the following detailed description and accompanying drawings.

[0022] FIG. 1 depicts a perspective view of a winch system incorporating counterbalances in the form of tension springs which provide a floating configuration for a table movable in a Cartesian x-axis and a Cartesian y-axis;

[0023] FIG. 2 depicts a schematic of a control system for the winch system of FIG. 1;

[0024] FIG. 3 depicts a simplified plan view of the reel of the winch system of FIG. 1 along with a portion of the spooling guide with the spooling guide aligned with a spooling location for a flexible member;

[0025] FIG. 4 depicts a simplified plan view the reel of the winch system of FIG. 1 along with a portion of the spooling guide with the spooling guide aligned with a spooling location for a flexible member after a full course of the flexible member has been spooled;

[0026] FIG. 5 depicts a simplified plan view the reel of the winch system of FIG. 1 along with a portion of the spooling guide with the spooling guide aligned with a spooling location for a flexible member after a maximum number of courses of the flexible member have been fully or partially spooled;

[0027] FIG. 6 depicts a simplified plan view the reel of the winch system of FIG. 1 along with a portion of the spooling guide with the spooling guide aligned with a spooling location for a flexible member after a maximum number of courses of the flexible member have been fully or partially spooled;

[0028] FIG. 7 depicts a simplified schematic view of drive wheels, a drive member, tension springs and winding cones of the winch system of FIG. 1 with a connecting member located in an initial position to show various forces in the system;

[0029] FIG. 8 depicts a simplified schematic view of the drive wheels, drive member, tension springs and winding cones of FIG. 7 after moving the connecting member to a second position to show various forces in the system;

[0030] FIG. 9 depicts the winch system of claim 1 with the counterbalance tension springs replaced with counterbalance linear spring; and

[0031] FIG. 10 depicts the winch system of claim 1 with the counterbalance tension springs replaced with counterbalance hydraulic/pneumatic cylinders.

DETAILED DESCRIPTION

[0032] For the purpose of promoting an understanding of the principles of the disclosure, reference will now be made to the embodiments illustrated in the drawings and described in the following written description. It is to be understood that no limitation to the scope of the disclosure is thereby intended. It is further to be understood that the present disclosure includes any alterations and modifications to the illustrated embodiments and includes further applications of the principles of the disclosure as would normally occur to one skilled in the art to which this disclosure pertains.

[0033] FIG. 1 shows a winch system 100 that includes a reel assembly 102 and a spooling guide assembly 104. The reel assembly 102 includes a reel 106 which includes two flanges 108/110 and a barrel section 112. The flanges 108/110 are shown at opposite ends of the barrel section 112 in FIG. 1. A reel motor 114 (see FIG. 2) is configured to rotate the reel 106 about a reel axis 116.

[0034] The spooling guide assembly 104 includes a frame 120 including two frame uprights 122/124. The frame 120 in some embodiments is fixed with respect to a support frame (not shown) of the reel assembly. In some embodiments, the frame 120 is integrally formed with, or directly fixedly attached to, a support frame (not shown) of the reel assembly. At least one of the two frame uprights 122/124 support a table motor 126 and rotatably support an upper drive shaft 128. The table motor 126 is configured to rotate the upper drive shaft 128 through a gear assembly 130.

[0035] Two drive wheels 132/134 are fixedly attached to the upper drive shaft 128 so as to rotate with the upper drive shaft 128. Drive components 136/138 are respectively engaged with the drive wheels 132/134 and with drive wheels 140/142. The drive wheels 140/142 are fixedly attached to a lower drive shaft 144 so as to rotate with the lower drive shaft 144. In various embodiments, the drive components 136/138 are belts or chains. The drive components 136/138 are fixedly coupled to a table assembly 148.

[0036] The table assembly 148 includes a frame member 146 which supports a table 150. The frame member 146 is configured to raise or lower the table 150 along guides 152/154 fixedly mounted to the frame uprights 122/124, respectively.

[0037] The table 150 supports a carriage motor 156 which is operably connected to a screw drive 158 through a gear assembly 160. A carriage 162 is operably connected to the screw drive 158 such that the carriage motor 156 can move the carriage 162 along a screw drive axis 164. The screw drive axis 164 is typically parallel to the reel axis 116. The carriage 162 is stabilized and guided by two support bars 166/168. A spooling guide 170, discussed in further detail below, is mounted to the carriage 162.

[0038] The spooling guide assembly 104 further includes a counterbalance support bracket 172 fixedly attached to the frame upright 124. The counterbalance support bracket 172 is fixedly attached to one end of a counterbalance which in this embodiment is in the form of a torsion spring 174. The bracket 172 functions as a stationary cone. The opposite end of the torsion spring 174 is connected to a winding cone 176 which is selectively rotationally fixedly attached to the upper drive shaft 128.

[0039] A second counterbalance support bracket 180 is fixedly attached to the frame upright 124. The counterbalance support bracket 180 is fixedly attached to one end of a counterbalance which in this embodiment is in the form of a torsion spring 182. The opposite end of the torsion spring 182 is connected to a winding cone 184 which is selectively rotationally fixedly attached to the lower drive shaft 144. In some embodiments the second counterbalance is omitted. While limiting the advantages obtained, a configuration with a single counterbalance advantageously counterbalances at least some of the weight of the table assembly.

[0040] Referring to FIG. 2, a control system 200 for the winch system 100 is depicted. The control system 200 includes a controller 202 which is operatively connected to a memory 204. Stored within the memory 204 are program instructions which, when executed by the controller 202 cause the various operations described herein to be executed. The controller 202 is further operably connected to a control input 206. The control input 206 in some embodiments is a keyboard which is optionally associated with a second controller (not shown).

[0041] The controller 202 is further operably connected to the reel motor 114, the table motor 126, and the carriage motor 156. A sensor array 208 includes any desired sensors for functioning and/or monitoring of the winch system 100. Sensors included within the sensor array is various embodiments include weight sensors configured to determine a weight of the table assembly 148 and/or a weight of a flexible member borne by the table assembly 148, position sensors configured to provide one or more of the spooling location (described further below) of the reel 106, the location of the frame member 146, the location of the table 150, the location of the carriage 162, the location of the spooling guide 170, etc.

[0042] In one embodiment, locations for the winch system are identified using a Cartesian system. For example, while any desired reference can be used, the screw drive axis 164 in some embodiments is set as a Cartesian x-axis. Additionally, a Cartesian y-axis is defined as a vertical axis extending perpendicular to the Cartesian x-axis such as the vertical axis 210 shown in FIG. 1. The origin of the Cartesian axes can be modified as desired. In the examples discussed herein, the Cartesian y-axis is aligned with a direction of gravitational force, but the embodiments are not limited to this configuration.

[0043] To prepare for operation, one of the torsion spring 174 and the torsion spring 182 is initially torsioned to support the weight of the table assembly 148 and optionally an additional weight of a flexible member expected to be applied to the table assembly during operation by rotation of the associated winding cone 176/184. In this embodiment, the winding cones 176/184 are motor operated. In some embodiments the sensor array 208 includes sensors configured to identify the weight of the table assembly and/or the weight of the flexible member supported by the table assembly. Accordingly, the controller 202 executes program instructions stored in the memory 204 to obtain weight data from the sensor array 208 and/or from lookup tables stored in the memory 204 and controls the winding cone 176/184 based upon the weight data. In some embodiments, the winding cones 176/184 are additionally and/or alternatively manually manipulated. In some embodiments, some or all of the weight of the table assembly and/or the weight of the flexible member supported by the table assembly is simply counterbalanced using a weight as discussed below.

[0044] Once the initial torsioning is completed, when using two counterbalances, both the torsion spring 174 and the torsion spring 182 are further torsioned to provide a floating configuration at a desired location as further discussed below. The controller 202 then continues executing program instructions stored in the memory 204 to perform a spooling operation as discussed with further reference to FIG. 3.

[0045] As shown in FIG. 3, the controller 202 has controlled the table motor 126 and the carriage motor 156 to position the spooling guide 170, shown in simplified form in FIG. 3, in alignment with a spooling location 212 of the reel 106. A spooling location is the location on the reel 106 at which a flexible member 214 initially contacts the reel 106 or a coil of the flexible member 214 positioned on the reel 106. The controller then controls the reel motor 114 to rotate the reel 106. As the reel 106 rotates, the flexible member 214 is guided by the spooling guide 170 to the spooling location 212.

[0046] As the reel 106 rotates, the controller 202 controls the carriage motor 156 to move the carriage 162 along the Cartesian x-axis which in this example is aligned with the screw drive axis 164. The controller synchronizes movement of the carriage 162 such that as the reel 106 completes a rotation, the carriage has moved, with reference to FIG. 3, to the left along the Cartesian x-axis by an amount that corresponds to a diameter of the flexible member 214. This continues until a desired amount of the flexible member 214 has been coiled or until the carriage 162 has been moved such that the spooling guide 170 is in alignment with a spooling location 212 of the reel 106 immediately adjacent to the flange 108 and the first course of spooled flexible member 214 is finished.

[0047] The spooling location 212 then moves from a position on the reel 106 to a position on the first spooled course of flexible member 214 as shown in FIG. 4. In FIG. 4, the controller 202 has controlled the table motor 126 to move along the Cartesian y-axis (vertical axis 210 of FIG. 1 in this example) in a direction away from the direction in which gravity is acting upon the table assembly 148 (gravity acts downwardly in the configuration of FIG. 1) by an amount corresponding to the diameter of the flexible member 214.

[0048] The controller 202 then continues to move only the carriage 162 along the Cartesian x-axis in the direction away from the flange 108 as the reel 106 rotates (see FIG. 5) to complete as many further full or partial courses of spooled flexible member 214 as desired while raising the table assembly 148 at the end of each course in the manner described above. De-spooling of the flexible member 214 is accomplished by reversing the process described above.

[0049] As noted above, at the end of each course of flexible member 214 spooled on the reel 106 the table assembly 148 is raised (or lowered for de-spooling). Raising/lowering the table assembly 148 results in modification of the force applied by the torsion spring 174 and the torsion spring 182. This is explained, along with the initial torsional loading of the system, with reference to FIGS. 6-8.

[0050] FIG. 7 is a simplified schematic drawing of FIG. 1 taken along the line VII-VII showing the drive wheels 132 and 140, the drive component 136 along with a connecting member 220 which connects to the table 150 such that movement of the drive component 136 results in movement of the table 150. While only a connecting member 220 on the drive component 136 is shown, a further connecting member is preferably provided on the drive component 138.

[0051] Also shown in FIG. 7 are the winding cones 176/184, the upper drive shaft 128, and the lower drive shaft 144. In this example, the torsion springs 174/182 are initially unloaded and the initial torsioning discussed above is applied to the torsion spring 174. This is accomplished by selectively rotationally releasing the winding cone 176 from the upper drive shaft 128 and rotating the winding cone 176 in a clockwise direction as indicated by the arrow 222 in FIG. 7 with respect to the upper drive shaft 128. This also rotates the torsion spring 174, which increases the torsion in the torsion spring 174, since one end of the torsion spring 174 is fixedly connected to the winding cone 176.

[0052] In this example, the clockwise rotation of the torsion spring 174 tightens the coils of the torsion spring 174 resulting in a torsional force in the direction of the arrow 224 of FIG. 7. The winding cone 176 is thus rotated in the clockwise direction until the force generated by the torsion spring 174 on the upper drive shaft 128 (a force in the direction of the arrow 224) will counterbalance the weight of the table assembly 148 at the connecting member 220 once the winding cone 176 is again fixed to the upper drive shaft 128. That is, the torsion spring 174 applies a force through the connecting member 220 in a direction (arrow 226) opposite to the direction of force (arrow 228) from the table assembly 148 resulting from gravity. To assist in this process, the spooling guide assembly 104 in some embodiments is provided with a brake (not shown) which holds the table assembly 148 and/or the upper drive shaft 128 (and/or lower drive shaft 144 when torsioning the torsion spring 182) in a desired location during the torsioning process. In some embodiments, some or all of the weight of the table assembly and/or the weight of the flexible member supported by the table assembly is additionally/alternatively counterbalanced using a counterbalance weight 216 positioned, for example, on the side of a drive component 136/138 opposite the location of the connecting member 220. This reduces the amount of tension required in the tension springs.

[0053] The torsion spring 174 is further torsioned (or initially torsioned when using a counterbalance weight for all of the weight of the table assembly 148) based upon a total rise in the table assembly 148 from the initial position (FIG. 3) to the height associated with the final course of the flexible member 214 (see FIG. 6). In particular, raising of the table assembly 148 is effected by rotation of the upper drive shaft 128 in the direction of the arrow 224. Accordingly, the torsion spring 174 is wound in a direction opposite to the direction in which the torsion spring was wound to increase torsion (arrow 222). Thus, the raising of the table assembly 148 results in a reduction in the torsional force generated by the torsion spring 174. The amount of this reduction is accounted for by further rotation of the winding cone 176 following the initial torsioning of the torsion spring 174. In some embodiments, a further excess torsioning is supplied to ensure sufficient counterbalancing of the system so that the entire weight of the table assembly (and possibly the weight of the flexible member 214 borne by the table assembly) is counterbalanced by the force applied by the connecting member 220 by the torsion spring 174 in the direction of the arrow 226. The winding cone 176 is then re-fixed (rotationally) to the upper drive shaft 128.

[0054] In order to counterbalance the additional (and further excess) force generated by the torsion spring 174 beyond that needed to counterbalance the table assembly 148, a further counterbalancing force is generated by the torsion spring 182 in the direction of the arrow 228. The torsion of the torsion spring 182 is modified much in the same manner as the torsion spring 174. Thus, the winding cone 184 is rotationally unlocked from the lower drive shaft 144 and rotated in the direction of the arrow 230 thereby causing the torsion spring 182 to be rotated in the direction of the arrow 230. The torsion spring 182, however, has a winding which is reversed from the winding of the torsion spring 174. Accordingly, rotation in the direction of the arrow 230 produces a torsional force from the torsion spring 182 in the direction of the arrow 231 resulting in a force being applied to the table assembly 148 through the connecting member 220 in the direction of the arrow 228.

[0055] The torsion of the torsion spring 182 is thus set to match all of the torsion of the torsion spring 174 with the exception of the torsion associated with the weight of the table assembly 148 (and in some embodiments the weight of the flexible member 214 that is to be borne by the table assembly 148). Consequently, when the system is adjusted and ready for initial spooling, the connecting member 220 will be located at a height which aligns the spooling guide 170 with the spooling location 212, and the net force on the connecting member 220 will be at or near zero. In particular, the force generated at the connecting member 220 in the direction of the arrow 226 by the torsion spring 174 will be matched/equal to the force in the direction of the arrow 228 resulting from the weight of the table assembly 148 (and in some embodiments the weight of the flexible member 214 that is to be borne by the table assembly 148) plus the force generated by the torsion spring 182. Thus, the system will be in a float condition. This allows for the use of a relatively small table motor 126, even with a very large/heavy table assembly.

[0056] Of course, the float condition is not maintained throughout the travel of the table 150/table assembly 148. FIG. 8 shows the configuration of FIG. 7 after the table 150/table assembly 148 has been raised by the distance D to a higher position. In raising the table 150/table assembly 148, the table motor 126 has rotated the upper drive shaft 128 in the direction of the arrow 224 of FIG. 7 through the gear assembly 130 causing the drive wheels 132/134 to rotate in the direction of the arrow 224 of FIG. 7. Rotation of the drive wheels 132/134 causes the drive components 136/138 to rotate in the direction of the arrow 224 resulting in rotation of the drive wheels 140/142 and lower drive shaft 144 in the direction of the arrow 224. Consequently, the connecting member 220 moves from the position of FIG. 7 to the position of FIG. 8 by the distance D, thereby moving the table 150/table assembly 148 and spooling guide 170 by the distance D.

[0057] The above-described rotation of the upper drive shaft 128 and the lower drive shaft 144 also causes the winding cones 176 and 184 to rotate in the direction of the arrow 224. Thus, both the torsion spring 174 and the torsion spring 182 are rotated in the direction of the arrow 224/230 which releases torsion of the torsion spring 174 and increases torsion of the torsion spring 182. The net force on the connecting member 220 is thus the combined change in the forces generated by the torsion spring 174 and the torsion spring 182. So long as the torsion spring 174 and the torsion spring 182 are selected to generate a change of force which is less than the force required to support the weight of the table assembly 148, the force required to be provided by the table motor 126 is reduced. Accordingly, the torsion spring 174 and the torsion spring 182 are selected to be very long relative (large number of coils) to the necessary movement of the table 150/table assembly 148.

[0058] Consequently, at the location depicted in FIG. 8, the force generated at the connecting member 220 in the direction of the arrow 226 by the torsion spring 174 will be less than the initial force generated by the torsion spring 174 in the position of FIG. 7, and the force generated by the torsion spring 182 in the position of FIG. 8 will be greater than the force generated by the torsion spring 182 in the position of FIG. 7.

[0059] So as to minimize the net difference in force, the system in some embodiments is configured to float at a location midway between the height of the table 150/table assembly 148 when the spooling guide is aligned with the top of the barrel section 112 (see FIG. 3), and the height of the table 150/table assembly 148 when the spooling guide is aligned with the top course of flexible material 214 when the maximum number of courses of the flexible material 214 are spooled on the reel 106 (see FIG. 6). In one embodiment, the float height is selected to be one-half the height of the flanges 108/110 above the barrel section 112 which is at the height 218 shown in FIG. 3.

[0060] While one particular spring winding arrangement has been discussed above, in other embodiments the windings are reversed. In some embodiments, the lower counterbalance is used to support the weight of the table assembly rather than the upper counterbalance. Additionally, while the counterbalances in the embodiment of FIG. 1 are provided in the form of torsion springs, in other embodiments other types and/or configurations of counterbalances are used. By way of example, FIG. 9 depicts an embodiment wherein the winch system 100 of FIG. 1 has been modified to include counterbalances in the form of linear springs 240/242. One end portion of the linear springs 240/242 are fixedly connected to the frame upright 124 by respective mounts 244/246 and opposite end portions are fixedly connected to the table 150 through respective table mounts 248/250.

[0061] The linear springs 240/242 provide the same counterbalancing function as the torsion springs in the embodiment of FIG. 1 by having one of the linear springs in compression while the other is in tension. Accordingly, a floating configuration can be provided for the table 150.

[0062] As a further example, FIG. 10 depicts an embodiment wherein the winch system 100 of FIG. 1 has been modified to include counterbalances in the form of pneumatic/hydraulic cylinders 260/262. One end of the pneumatic/hydraulic cylinders 260/262 are fixedly connected to the frame upright 124 by respective mounts 264/266 and opposite ends are fixedly connected to the table 150 through respective table mounts 268/270.

[0063] The pneumatic/hydraulic cylinders 260/262 provide the same counterbalancing function as the torsion springs in the embodiment of FIG. 1 by having one of the pneumatic/hydraulic cylinders 260/262 in compression while the other is in tension. Accordingly, a floating configuration can be provided for table 150.

[0064] While the disclosure has been illustrated and described in detail in the drawings and foregoing description, the same should be considered as illustrative and not restrictive in character. It is understood that only the preferred embodiments have been presented and that all changes, modifications and further applications that come within the spirit of the disclosure are desired to be protected.