CONTROL DISPLAY POSITIONING SYSTEM FIELD

The present invention pertains to positioning systems for control displays; more particularly, the present invention pertains to a control display positioning system used with medical/surgical equipment.

BACKGROUND

Prior art medical/surgical systems such as ophthalmic surgical systems with control displays provide limited access to the control display, touch screen, and graphical user interface (GUI). In some medical/surgical systems, the control display is permanently affixed to the front panel of the machine so that it cannot be moved. In other medical/surgical systems, the control display is mounted on a yoke-type device so that the control display can both spin from side to side about a vertical axis and also tilt about a horizontal axis. However, since the display is still centered on and mounted to the medical/surgical system, the health care professional is still restricted to accessing the control display from a position directly in front of the machine.

Restricting the control display to a position directly in front of a medical/surgical system is a problem in a medical/surgical setup where trays of surgical tools and devices must often be placed directly in front of the system. In this configuration, a health professional must reach over the surgical tools and devices to gain access to the control display. Such positioning of the control display risks compromising the sterile field near the machine and over the surgical tools and devices.

Another situation that presents difficulty is accessing the GUI when the patient is positioned between the medical/surgical system and the user. In this situation, the user must reach over the patient to access the GUI. Yet another problem is accommodating the body position of the health care professional using the medical/surgical system. In some procedures the health care

professional is more comfortable working from a sitting position. In other procedures the heath care professional is more comfortable working from a standing position. Whether seated or standing, the height of the health care professional is also a major concern. This is because a health care professional can misread the screen because the screen is not properly positioned to provide a clear line of sight. Misreading the screen could result in an improper and possibly unsafe step in a surgical procedure. Accordingly, the proper placement of a control display with respect to the eyes of a health care professional to avoid glare from the screen, reflections from room lighting, or distortions of the images appearing on the control display is essential. It has also been found that the pivoting of prior art control display positioning systems into different orientations causes twisting of the cables housed within the control display positioning system. This twisting of the cables places a mechanical stress on the cables. This mechanical stress will eventually cause the cables to break. In some prior art systems the cables leading to a control display are wrapped into tight coils. In other prior art systems, movement of the cables is restricted at each cable end. This restricting of the movement of the cables at each end is done so that the mechanical stress caused by movement of the cable on each axis could be reduced axis by axis.

The problem with the axis by axis restriction on cable movement is that the cables must be quite long because the length of the cable needed to handle the rotation in each axis is additive. The increased cable length is required to be stored in a relatively large coil. The need to store a relatively large coil of cable increases the overall size of the control display positioning system. When several cable movement axes are used in series, the length of the cable necessitates a significant increase in the size of the control display positioning system. It has also been found that using coiled cables and restricting movement of the cable ends is not an acceptable solution when multiple cables are used. Further, it has also been found that it is advantageous to separate video signal

transmission cables from other cables to reduce the amount of noise added to the video signal.

Another problem with prior art control display positioning systems is that the spring force, used to push friction generation surfaces together, is typically created by the compression of a series of wave washers. Because individual wave washers provide a relatively low level of force when compressed, several wave washers must be used in series to generate the amount of force needed to press on the friction generation surfaces.

Wave washers also are characterized by a linear deflection to force curve (spring rates).

As a result, variations in the deflection of the wave washers caused by a variation in the dimensions of the wave washers and their mating parts cause a large variation in spring force. This large variation in spring force, in turn, results in a large variation in frictional force.

Accordingly, there remains a need in the art for a control display positioning system that is usable with a piece of medical/surgical equipment that: a) adjusts the position of the control to display to where it can be best seen by a health care professional; b) reduces the mechanical stress on the electrical cables providing electrical signals to the control display; c) provides a wide range of motion for the control display, and d) retains its position when manually repositioned.

SUMMARY The control display positioning system of the present invention permits adjusting the position of the control display to a wide variety of positions where it can best be seen by a health care professional; reduces the mechanical stress on the cables providing electrical signals to the control display and retains its position when manually repositioned. The disclosed control display positioning system features three hinges ~ each having a substantially vertical axis to provide rotational movement in a substantially

horizontal plane. The first or base vertical hinge is mounted to a stationary portion of a piece of medical/surgical equipment. Extending outwardly from the proximal end of the base vertical hinge is a first arm. At the opposite or distal end of the first arm is located the second or elbow vertical hinge. Extending outwardly from the proximal end of the elbow vertical hinge is a second arm. At the distal end of the second arm is located a third or display vertical hinge. Connecting the display vertical hinge to the control display is a control display mounting or horizontal hinge to move the control display with respect to a substantially vertical plane. The horizontal hinge is mounted to the back of the control display. Within each vertical hinge is a substantially cylindrical passage. The cable bundle which provides electrical signals to the control display passes through this substantially cylindrical passage.

Surrounding the substantially cylindrical passage within each vertical hinge is a friction mechanism for holding each vertical hinge in a selected position. The friction mechanism for holding each vertical hinge in a selected position includes a stack of washers. Friction forces are created by the contact between a friction washer and a steel washer. The force pushing the friction washer and the steel washer together is provided by a stack of one or more Belleville washers.

BRIEF DESCRIPTION OF THE DRAWING FIGURES A still better understanding of the control display positioning system of the present invention may be had by reference to the drawing figures wherein:

Figure 1 is a perspective view of the control display positioning system of the present invention mounted to a stationary portion of a piece of medical/surgical equipment; Figure 2A is a side, sectional of the vertically oriented hinge used in the disclosed invention;

Figure 2B is a side, sectional view of the horizontally oriented hinge used in the disclosed invention; and

Figure 3 is an exploded perspective view of the horizontally oriented hinge attached to the back of the control display for tilting the control display with respect to a vertical plane and the display mounting vertical hinge. DESCRIPTION OF THE EMBODIMENTS

The disclosed control display positioning system 10 as shown in Figure 1 is used to support and position a control display 90 for a medical/surgical system 100 such as an ophthalmic surgical system. Those of ordinary skill in the art will understand that the disclosed system 10 may also be used with other types of medical/surgical equipment.

An important feature of the disclosed system 10 is that the cables 110 which deliver electrical energy and signals to the electronic components housed within the control display 90 are contained within the control display positioning system 10.

Another feature of the disclosed control display positioning system 10 is that the frictional force within the hinges 20, 30, 50, 70 keeps the control display 90 at any selected position. The health care professional repositions the control display 90 simply by applying sufficient force to overcome the frictional force within the hinges 20, 30, 50,

70. The result is that the disclosed control display positioning system 10 enables the control display 90 to be placed and remain in any position within a semi-circular area about the front or either side of the medical/surgical system 100.

The control display 90 includes a graphical user interface (GUI) 91 having a touch panel or touch screen 92. It is the touch panel 92 which acts as the primary user input device for the system 100. The 4 axis arm movement of the disclosed control display positioning system 10 allows the control display 90 to be located in positions ranging from the center of the machine, to over the patient, to a position extended out in front of or to the sides of the piece of medical/surgical equipment. This increased range of motion

facilitates access to the display by nurses who may be acting in several different operational roles during a medical/surgical procedure.

The disclosed control display positioning system 10 includes 3 vertical spin axes Vi, V ₂ , V ₃ through each hinge 30, 50, 70 and one horizontal tilt axis H ₁ , through the remaining hinge 20. The 3 vertical spin axes Vi, V ₂ , and V ₃ allow the disclosed control display positioning system 10 to move the control display 90 to any position in a horizontal plane parallel to the floor within its range of motion. The horizontal tilt axis Hi provided by the hinge 20 allows the viewing angle of the display 90 to be adjusted by + 20° with respect to a vertical plane to accommodate users of different heights. Both the vertically oriented hinges 30, 50, 70 and the horizontally oriented hinge

20 have friction generating mechanisms as shown generally in Figures 2A and 2B, respectively, to create drag and allow each arm 40 and 60 to remain in position once placed there. In the vertical axes Vi ₁ V ₂₁ V ₃ , friction is created by pressing a stainless steel washer 102 against a plastic friction washer 104 as shown in Figure 2A. Belleville washers 106 that have a non-linear spring constant are used to create the load on washer 102. The Belleville washers 106 reduce the fluctuation in frictional load.

It has been found that more consistent frictional force is achieved by using Belleville washers 106 with nonlinear spring rates. The Belleville washers 106 selected for use in the disclosed invention are specifically designed so that the deflection is in a very flat section of their force curve. The result is that variations in the deflection caused by stacked up tolerance variations result in very small changes in the normal force applied to the friction washer 104.

Included within each vertical hinge assembly is an inner race spanner nut 11, an outer race spanner nut 13 and a ball bearing 15. While a ball bearing 15 has been used in the preferred embodiment, those of ordinary skill in this will understand that other types of bearings may be used without departing from the scope of the invention. At the

bottom of each vertical hinge assembly is a rotation limitation ring 16. One or more caps or covers 17 may be included to keep dirt and debris out of the hinge assembly. Hinge assemblies 30, 50 and 70 are each contained within a housing 18 that is rotationally coupled to outer race spanner nut 13. Hinge assemblies 30, 50 and 70 each have a hinge shaft 19 that is rotationally coupled to inner race spanner nut 11. The rotation of hinges 30 and 70 is limited to 180°; while the rotation of hinge 50 is a full 360°.

The display vertical hinge assembly 70 is attached to the distal end 62 of the first arm 60. At the opposite end 64 of the first arm 60 is located the elbow vertical hinge assembly 50. The elbow vertical hinge assembly 50 provides a connection between the end 64 of the first arm 60 and the distal end 42 of the second arm 40. At the opposite end 44 of the second arm 40 is located the base vertical hinge assembly 30. The base vertical hinge assembly 30 is connected to a stationary portion of medical/surgical system 100.

There is sufficient space within each hinge assembly 30, 50, 70 so that several cables may be routed through the center bore 12 of the hinges. These cables may include an LVDS Signal Cable, an interface data cable, and a cable grouping strap. By allowing the cables to pass in an unrestricted manner through the center bore 12 of the hinge assemblies 30, 50, 70 at all 3 spin axes, mechanical stress in the cables and the resulting cable failure is reduced.

Cable length and cable stress is further reduced by running the cable through an open space 99 running the length of each arm 40, 60 as shown in Figure 3. This reduction of cable stress occurs for two reasons. First, by allowing the path for cable travel to be unrestricted between vertical axes, the twisting motion of one axis can cancel out the opposing twisting motion of a neighboring axis. Additionally, leaving the path 99 for cable travel unrestricted throughout the entire length of each arm 40, 60 allows for a greater cable length. This greater cable length allows for any given annular deflection to be distributed over a longer section of cable thus reducing any mechanical stress

concentration in the cable. If the cable were strain-relieved at either end of each axis as in prior art systems, the angular deflection would to be concentrated over only a couple of inches of cable. It has been found that by strain-relieving the cable at the beginning and at the end of the series of axes, the length that the angular deflection may be distributed over is increased to over 12 inches.

Referring to Figure 3, there are two vertical bars 24 on which the control display 90 is mounted. Bars 24 are connected to the control display mounting or horizontal hinge assembly 20, which provides tilting of the control display 90 about a substantially horizontal axis. Horizontal hinge assembly 20 is connected to display vertical hinge assembly 70.

By comparing Figure 3 to Figure 2B, it may be seen that shaft 22 passes through holes 21 in each vertical bar 24. Each end of the shaft 22 receives a screw 23 within an internally threaded portion 25. Horizontal hinge assembly 20 further includes a stainless steel shim washer 112, a plastic friction washer 114, and a set of Belleville washers 116. Tightening of the screw 23 compresses Belleville washers 116 against bar 24 and friction washer 114 to provide the necessary frictional force to maintain the tilt of the control display 90 about the horizontal axis H ₁ . Similar to Belleville washers 106 in hinge assemblies 30, 50, and 70, Belleville washers 116 have a non-linear spring constant that reduce the fluctuation in frictional load. While the disclosed control display positioning system has been disclosed according to its preferred embodiment, those of ordinary skill in the art will understand that numerous other embodiments have been enabled by the foregoing disclosure. Such other embodiments shall be included within the scope and meaning of the appended claims.