Abstract:
An operator presence control assembly for a walk-behind greens mower includes a handle supported on a frame of the walk-behind greens mower, a ribbon switch on the outer perimeter of the handle, and a circuit including the ribbon switch. The circuit is completed by applying a threshold pressure to the ribbon switch, and a device selectively energizeable via the circuit in accordance with the threshold pressure applied to the ribbon switch. As the user of the greens mower grips the handle, the ribbon switch completes a circuit to energize a switch to engage an electromagnetic clutch.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. patent application Ser. No. 10/872,189, filed on Jun. 18, 2004. The disclosure of the above application is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a walk-behind greens mower and, more particularly, to an operator presence control system for a walk-behind greens mower. 
     BACKGROUND OF THE INVENTION 
     Operator presence features are common in walk-behind reel mowers and rotary mowers. Typically, the mower is provided with a lever, also known as a bale, which can be moved between an engaged and disengaged position. The bale engages cable links, springs, and other mechanical components in order to enable a micro-switch and activate the cutting mechanism. However, it should be understood that these systems require additional mechanical components that increase the cost of the mower and further increase the complexity of operation of the operator presence control system. 
     Therefore, while the existing operator presence control mechanisms may operate sufficiently, it is desirable to provide a walk-behind reel mower with an operator presence control having a reduced number of components, simplified operation, and improved reliability. 
     SUMMARY OF THE INVENTION 
     The present invention relates to an operator presence control assembly for a walk-behind greens mower. The operator pressure control assembly includes a handle supported on a frame of the walk-behind greens mower and a ribbon switch mounted on the outer perimeter of the handle. An electrical circuit, including the ribbon switch, is energized in response to application of a threshold pressure to the ribbon switch, which causes a device to be selectively energized. 
     The present invention further relates to a walk-behind greens mower having a frame, a power source coupled to the frame, a traction roller coupled to the frame and drivingly connected to the power source, and a reel rotatably mounted to the frame and selectively driven by the power source. An electromagnetic clutch is further provided for transferring power from the power source to the traction roller and the reel, whereby the electromagnetic clutch is interposed between the power source and a transmission. An electric circuit is electrically connected between the power source and the electromagnetic clutch. The electric circuit includes a rectifier connected to the power source, a ribbon switch connected to the rectifier, and an electromagnet interposed between the ribbon switch and the electromagnetic clutch. 
     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
         FIG. 1  illustrates an exploded view of a greens mower constructed in accordance with the teachings of the present invention; 
         FIG. 2  is a circuit diagram of a ribbon switch used in accordance with the teachings of the present invention; 
         FIG. 3  is a perspective view of one embodiment of the operator control assembly constructed in accordance with the teachings of the present invention; 
         FIG. 4  is a block diagram of an operator presence control system in accordance with the teachings of the present invention; and 
         FIGS. 5   a  through  5   d  display different configurations of the ribbon switch and handle in accordance with the teachings of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
     Referring to  FIG. 1 , a walk-behind greens mower constructed in accordance with the teachings of the present invention is depicted at reference number  10 . While the operator control assembly of the present invention is shown in conjunction with a walk-behind greens mower powered by an internal combustion engine, other devices may incorporate the same operator control assembly. Furthermore, these devices may utilize electric motors, hybrid power sources, or the like. For example, any walk-behind device such as a blower, string trimmer, or mower may incorporate the operator control assembly of the present invention. Additionally, the invention described herein will be illustrated in the context of an articulating handle. One skilled in the art will recognize that the subject of the present invention will be equally applicable to various articulating and non-articulating configurations. 
     Mower  10  includes a cutting unit  12  and an operator control assembly  14 . Typically, cutting unit  12  includes a power source or engine  15  coupled to a frame  16 . Traction roller  18  is rotatably coupled to frame  16  and drivingly connected to engine  15 . Reel  20  includes blades  22  rotatably mounted to frame  16  and is selectively driven by engine  15 . A transmission  24  is also included on the frame  16 . Between transmission  24  and engine  15  is an electromagnetic clutch  26 . Electromagnetic clutch  26  is responsible for selectively transferring power from engine  15  to traction roller  18  and reel  20 . Wheels  28  are connected to traction roller  18  to provide motive force for translating mower  10  along the ground. 
     Electromagnetic clutch  26  is controlled by means of operator presence control assembly  14 . Operator presence control assembly  14  comprises a handle  30  with a ribbon switch  32 . Ribbon switch  32  electrically connects with a micro-switch  36 . Micro-switch  36  connects to electromagnetic clutch  26  to enable engine  15  to engage transmission  24 . 
     Referring now to  FIG. 2 , this figure shows a basic circuit diagram demonstrating the electrical significance of ribbon switch  32 . A voltage source  38  is connected to one end of ribbon switch  32 , while an electrical load  40  is connected to a second end of ribbon switch  32 . As the minimum threshold pressure is applied to ribbon switch  32 , the circuit is complete and current can flow from voltage source  38  to electrical load  40 . When the pressure applied to ribbon switch  32  falls below the threshold pressure, the circuit opens and current can not flow from voltage source  38  to electrical load  40 . In one configuration of the present invention, voltage source  38  is replaced by engine  15  or a battery, and electrical load  40  is replaced by micro-switch  36 . 
       FIG. 3  illustrates operator control assembly  14  in greater detail. As previously stated, operator control assembly  14  consists of handle  30 , ribbon switch  32 , and micro-switch  36 . Handle  30  connects to a support arm  39 , which is coupled to frame  16 . Ribbon switch  32  is attached to handle  30  and is electrically connected to micro-switch  36  through leads  34 . Micro-switch  36  is further electrically connected to electromagnetic clutch  26 . When energized, electromagnetic clutch  26  causes engine  15  to engage transmission  24 . 
     In order for ribbon switch  32  to complete a circuit, the mower operator must apply the minimum threshold pressure as previously stated. Once the operator applies the minimum threshold pressure, ribbon switch  32  conducts current. The minimum threshold pressure required for ribbon switch  32  to conduct electricity preferably is selected so that the operator can apply such pressure by comfortably gripping handle  30  on which ribbon switch  32  is attached. When the mower operator releases handle  30 , ribbon switch  32  opens and stops conducting current. This action disables micro-switch  36 , which de-energizes electromagnetic clutch  26 . 
       FIG. 4  is a block diagram of a control system  40  typically associated with the operator control assembly of the present invention. Control system  40  includes a power source  42 . Power source  42  can be either alternating current (AC) or direct current (DC) supplied by a device driver by engine  15  or a battery. Depending on the type of device, power source  42  delivers either an AC or DC signal to a rectifier or converter  44 . If the signal is AC, rectifier  44  converts the AC signal to a DC signal. If the power source is DC, converter  44  adjusts the DC level to that required by micro-switch  36 . Ribbon switch  32  is interposed between rectifier or converter  44  and micro-switch  36 . When ribbon switch  32  senses pressure sufficient to complete the circuit, the DC signal is transmitted to micro-switch  36 . When ribbon switch  32  does not sense sufficient pressure to complete the circuit, micro-switch  36  is de-energized. Micro-switch  36 , when energized, engages electromagnetic clutch  26 , such that, the power from engine  15  travels to transmission  24 , allowing reel  20  to turn. 
     Referring now to  FIGS. 5   a  through  5   c , these figures illustrate various methods of attaching ribbon switch  32  to handle  30 . These arrangements are merely exemplary in nature, and other similar variations that do not depart from the invention are intended to be within the scope of the invention. First, referring to  FIG. 5   a , ribbon switch  32  wraps around the outer perimeter of handle  30  and connects to micro-switch through leads  34 . This arrangement allows the user to grip handle  30  with only one hand to complete the circuit and activate micro-switch  36 . 
     Alternatively,  FIG. 5   b  illustrates a two-handed configuration. In this arrangement, ribbon switch  32  is arranged around handle  30  in such a way that both of the operator&#39;s hands must be present on handle  30  in order for the circuit to be complete. Ribbon switch  32   a  is electrically connected in series with ribbon switch  32   b  through leads  34   a , and connects to micro-switch  36  through leads  34 . Both switches must be closed in order enable micro-switch  36 . Therefore, if the mower operator takes one or both hands off of handle  30 , micro-switch  36  will be disabled, de-energizing electromagnetic clutch  26 . A parallel connection of ribbon switches  32   a  and  32   b  may enable the operator to use either hand to enable energization of microswitch  36 . 
     Next,  FIG. 5   c  shows ribbon switch  32  embedded in handle  30 . Embedding ribbon switch  32  into handle  30  makes the existence of ribbon switch  32  unknown to the user. One method of embedding ribbon switch  32  onto handle  30  is to place an elastomer  50  over the combination of ribbon switch  32  and handle  30 . Coating ribbon switch  32  and handle  30  with elastomer  50  makes the presence of ribbon switch  32  unknown to the mower operator.  FIG. 5   c  shows elastomer  50  only covering half of ribbon switch  32 , however, ideally, elastomer  50  would cover ribbon switch  32  completely. Furthermore, although  FIG. 5   c  shows a one-handed configuration, ribbon switch  32  could be embedded in handle  30  such that two hands are required to complete the circuit, as demonstrated in  FIG. 5   d . In  FIG. 5   d , ribbon switch  32   a  and  32   b  are completely covered by elastomer  50 . 
     Ribbon switch  32  attaches to handle  30  through any number of ways. For example, ribbon switch  32  may simply wrap around handle  30  forming a new layer on the outer perimeter. Alternatively, ribbon switch  32  could have an adhesive side that would stick to handle  30  by simply placing a strip across the handle. With this method, ribbon switch  32  could be placed on the top or bottom side of handle  30 . Either of these methods allow ribbon switch  32  and handle  30  to be coated with elastomer  50  to render ribbon switch  32  invisible to the mower operator. 
     The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.