Abstract:
An improved footswitch is disclosed. The footswitch may have an adjustable length treadle to accommodate different size feet. The footswitch may also have a treadle having a slidable plate that facilitates the actuation of a side switch.

Description:
This application claims the priority of U.S. Provisional Application No. 60/520,381 filed Nov. 13, 2003. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to the field of footswitches; more particularly to footswitches used to control patient treatment apparatus used by physicians, surgeons, dentists, veterinarians, etc. 
     DESCRIPTION OF THE RELATED ART 
     During the use of a complex patient treatment apparatus; for example, the handpiece used when performing ophthalmic surgery, the control of a variety of different subsystems such as pneumatic and electronically driven sub-systems is required. Typically, the operation of the sub-systems included in a complex patient treatment apparatus is controlled by a microprocessor-driven console that receives mechanical inputs from either the user of the device or from an assistant. A control device, generically known as a footswitch, is often used for receiving the mechanical inputs which originate from the movement of the foot of a user to govern the operation of a sub-system. The mechanical inputs from the movement of the foot of the user become electrical signals which are used to control the operational characteristics of a subsystem in a complex patient treatment apparatus. 
     Examples of footswitches that are designed for receiving mechanical inputs from the movement of the foot of a user operating a complex patient treatment apparatus may be found in U.S. patents, including U.S. Pat. No. 4,837,857 (Scheller, et al.); U.S. Pat. No. 4,965,417 (Massie); U.S. Pat. No. 4,983,901 (Lehmer); U.S. Pat. No. 5,091,656 (Gahn); U.S. Pat. No. 5,268,624 (Zanger); U.S. Pat. No. 5,554,894 (Sepielli); U.S. Pat. No. 5,580,347 (Reimels); U.S. Pat. No. 5,635,777 (Telymonde, et al.); U.S. Pat. No. 5,787,760 (Thorlakson); U.S. Pat. No. 5,983,749 (Holtorf); and U.S. Pat. No. 6,179,829 B1 (Bisch, et al.); and in International Patent Application Publication Nos. WO 98/08442 (Bisch, et al.); WO 00/12037 (Chen); and WO 02/01310 (Chen). These aforementioned patents and patent applications focus primarily on footswitches which include a foot pedal or tiltable treadle. The movement of the foot pedal or tiltable treadle typically provides a linear control input such as may be used, for example, for regulating rotational speed, power, or reciprocal motion. 
     In more complex footswitch assemblies, side or wing switches are typically located on either side of the foot pedal or tiltable treadle. The condition of these side or wing switches is changed by the application of pressure from the front portion of the user&#39;s foot or from the rear portion of the user&#39;s foot. However, given the ever-increasing complexity of patient treatment apparatus, there remains a need in the art to provide additional control features on a footswitch; while, at the same time, not making the footswitch overly complex. It has been found that one of the most usable additional control features would be a second separate proportional control input beyond the linear control input provided by a single foot pedal or tiltable treadle. In addition, there is a need to assure that the footswitch is ergonomically sound to minimize fatigue of the user&#39;s foot or leg, as such fatigue may cause improper control inputs. Such improper control inputs have the potential of injuring a patient. 
     SUMMARY OF THE INVENTION 
     In one aspect, the present invention is a footswitch including a base assembly and a pivotable treadle mounted on the base assembly for providing a control output. The treadle has an adjustable length to accommodate different size feet. 
     In another aspect, the present invention is a footswitch including a base assembly, a side switch mounted on the base assembly for providing a first control output; and a pivotable treadle mounted on the base assembly for providing a second control output. The treadle has a top surface and a plate on the top surface. The plate is slidably disposed along a linear path relative to the top surface so as to facilitate actuation of the side switch by the user&#39;s foot. 
     The present invention minimizes fatigue of the user&#39;s foot or leg and helps to insure proper use of the footswitch. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present invention, and for further objects and advantages thereof, reference is made to the following description taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a perspective view of the dual control footswitch assembly of the present invention; 
         FIG. 2  is an elevational view in partial section of the disclosed footswitch assembly; and 
         FIG. 3  is an enlarged elevational view in partial section of the encircled portion of the heel support assembly shown in  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The preferred embodiments of the present invention and their advantages are best understood by referring to  FIGS. 1 through 3  of the drawings, like numerals being used for like and corresponding parts of the various drawings. 
     As best seen in  FIG. 1  and  FIG. 2 , a preferred embodiment of the footswitch assembly  10  of the present invention generally includes a bottom housing  12 , a top housing  14 , a foot pedal or tiltable treadle  16 , a separate heel cup assembly  18 , a handle position H in the front, and side or wing switches  20 . 
     Attached to the foot pedal or tiltable treadle  16  is a DC motor/encoder  22 . The angular position of the foot pedal or treadle  16 , which is tiltable with respect to a horizontal plane or to a neutral or home plane, provides the first system for converting of mechanical input from movement of the user&#39;s foot into an electrical signal. Thus, the movement of the foot pedal or tiltable treadle  16  provides a proportional control input, which is preferably a linear control input. 
     As shown in the drawing figures, the footswitch assembly  10  of the present invention provides a second separate proportional control input using the disclosed construction of the heel cup assembly  18 . The heel cup assembly  18  is positioned at the rear portion of the footswitch  10  to engage the user&#39;s heel. The heel cup assembly  18  is positioned over a thrust bearing assembly  28 . Such construction allows the user to rotate the heel cup assembly  18  through an arcuate path while the user&#39;s heel effectively remains in the same spot. 
     In the preferred embodiment and as shown in  FIG. 3 , a shaft  30  is attached to the bottom of the heel cup assembly  18 . The shaft  30  is connected to a first bevel gear  32 . The first bevel gear  32  is positioned to be in mating engagement with a second bevel gear  34 . As the heel cup assembly  18  is rotated in an arcuate motion as shown by the arrow marked A″ in  FIG. 1 , the shaft  30  also rotates. This rotational motion causes rotation of the first bevel gear  32 . The contact between the teeth on the first bevel gear  32  and the teeth on the second bevel gear  34  rotates a shaft  36  which is connected to an angular position potentiometer  38 . This mechanical input into the angular position potentiometer  38  provides an electrical signal. The electrical signal from the potentiometer  38  is the second control signal. This control signal may be either linear or non-linear. In an alternate construction, the potentiometer  38  could be placed directly under the heel of the user. 
     To further enhance control of the second control signal, a simple on/off switch, well known to those of ordinary skill in the art, may be included in the heel cup assembly  18  to activate the signal output from the potentiometer  38 . Alternatively, such on/off switches could also be used to prevent inadvertent activation of the side switches  20 . Such on/off switch may be a slide switch moving along the linear path within the heel cup assembly  18  as is designated by the arrow marked A′ illustrated in  FIG. 1 . In another embodiment, heel cup assembly  18  has a plate  39  that is slidable along the linear path marked by arrow A′ under the application of a force by the user&#39;s foot. This movement of plate  39  also actuates the on/off switch. The on/off switch may be a Hall effect sensor. The user will be able to change the condition of this switch irrespective of the rotational position of the heel cup assembly  18 . 
     Further on  FIG. 1 , foot pedal or treadle  16  may be composed of a base structure  46  and a plate  48 . Base structure  46  is tiltable or pivotable with respect to a horizontal plane or to a neutral or home plane, as decribed above. Base structure  46  is preferably received by flanges  50  and  52  of plate  48 . Plate  48  is movable with respect to base structure  46  along the linear path marked by arrow B in  FIG. 1 , and may preferably be adjusted to selected positions along this path. An end  54  of plate  48  may thus be adjusted closer to or farther away from heel cup assembly  18  to adjust the length of treadle  16  to accommodate different size feet. 
     Still further on  FIG. 1 , foot pedal or treadle  16  may have an anti-friction plate  56  on a top surface  58  of plate  48 . Plate  56  is slidably disposed on top surface  58  along the linear path marked by arrow C in  FIG. 1 . Plate  56  is thus movable from side to side to facilitate a user&#39;s ability to actuate side or wing switches  20 . 
     In yet another embodiment, a mechanical or electrical latching mechanism  40 , well known to those of ordinary skill in the art, may be included to release the heel cup assembly  18 , and thus allow it to rotate. In the preferred embodiment, a return spring  44  is also included to allow the entire heel cup assembly  18  to return it to a home or neutral position. 
     While the present system and method has been disclosed according to the preferred embodiment of the invention, those of ordinary skill in the art will understand that other embodiments have also been enabled. Such other embodiments shall fall within the scope and meaning of the appended claims.