Patent Publication Number: US-2020291591-A1

Title: Snow blower implement

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 62/818,467, which was filed on Mar. 14, 2019. 
    
    
     BACKGROUND 
     The present disclosure is related to implements and accessories for implements that are attachable to power machines. More particularly, the present disclosure is related to implements or implement accessories that include a snow blower with an auger housing. 
     Power machines, for the purposes of this disclosure, include any type of machine that generates power to accomplish a particular task or a variety of tasks. One type of power machine is a work vehicle. Work vehicles are generally self-propelled vehicles that have a work device, such as a lift arm (although some work vehicles can have other work devices) that can be manipulated to perform a work function. Some examples of work vehicle power machines include loaders, excavators, utility vehicles, tractors, and trenchers, to name a few. 
     One type of implement is a snow blower having an auger housing with an auger that rotates to urge snow or other material to an impeller. The impeller can then drive the snow or material upwardly through a discharge chute. Such a snow blower with an auger and an impeller is commonly as a two-stage snow blower. Typically, it is difficult for an operator of the power machine on which the snow blower implement is mounted to have a clear view of the area directly in front of the auger housing of the implement. The housing itself blocks the operator&#39;s view, potentially allowing the implement to come into contact with objects or materials which were not intended. This can result in damage to the snow blower or to the objects or materials. 
     The discussion in this Background is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter. 
     SUMMARY 
     This Summary and the Abstract are provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. The summary and the abstract are not intended to identify key features or essential features of the claimed subject matter. 
     Disclosed embodiments include snow blower implements having an auger housing with one or more groups of apertures formed in a top or back wall in a pattern or arrangement to provide visibility through the housing, while minimizing material passing through the apertures. 
     In accordance with disclosed embodiments, one general aspect includes an implement ( 100 ;  100 ′;  100 ″;  200 ;  300 ;  400 ) configured to be coupled to an implement interface ( 40 ) of a power machine ( 10 ), the implement including: a power machine interface ( 110 ;  110 ′;  110 ″;  210 ;  310 ;  410 ) having a machine mount ( 112 ;  112 ′;  112 ″;  212 ;  312 ;  412 ) configured to engage the implement interface of the power machine; and a tool ( 120 ;  120 ′;  120 ″;  220 ;  320 ;  400 ) coupled to the power machine interface, the tool having a frame ( 122 ;  122 ′;  122 ″;  222 ;  322 ;  422 ) forming a housing, where the housing includes at least one aperture ( 262 ;  264 ;  362 ;  364 ;  462 ;  464 ;  466 ;  468 ) formed in the housing configured and arranged to provide an operator of the power machine with visibility, through the at least one aperture, of an implement workspace while operating the power machine. 
     Implementations may include one or more of the following features. The implement where the housing includes first and second spaced apart side plates ( 240 ;  242 ;  340 ;  342 ;  440 ;  442 ) on outer sides of the implement, and at least one laterally extending section ( 244 ;  246 ;  248 ;  344 ;  348 ;  444 ;  446 ) between the first and second spaced apart side plates, where the at least one aperture is formed in the at least one laterally extending section. The implement where the at least one laterally extending section includes a curved back wall ( 344 ) and where the at least one aperture is formed in the curved back wall. 
     The implement where the implement is a snow blower, where the housing is an auger housing, and where the at least one laterally extending section includes a bottom plate ( 348 ) extending between the side plates and configured to function as a scraper to scoop snow into the housing. 
     The implement where the implement is a snow blower, where the housing is an auger housing, and where the at least one laterally extending section includes a rear wall ( 244 ), a top wall ( 246 ) extending between the side plates, and a bottom plate ( 248 ) extending between the side plates and configured to function as a scraper to scoop snow into the housing. The implement where the at least one aperture is formed in the top wall of the housing. 
     The implement where the at least one aperture includes at least one group of apertures formed in the housing. The implement where the at least one group of apertures formed in the housing includes at least one diagonally oriented slot formed in the housing. The implement where the at least one group of apertures includes a plurality of diagonally oriented slots arranged parallel to each other. 
     The implement where the implement is a bucket ( 400 ). 
     Another general aspect includes a snow blower implement ( 100 ;  100 ′;  100 ″;  200 ;  300 ) configured to be coupled to an implement interface ( 40 ) of a power machine ( 10 ), the snow blower implement including: a power machine interface ( 110 ;  110 ′;  110 ″;  210 ;  310 ) having a machine mount ( 112 ;  112 ′;  112 ″;  212 ;  312 ) configured to engage the implement interface of the power machine; and a rotary snow blowing tool ( 120 ;  120 ′;  120 ″;  220 ;  320 ) coupled to the power machine interface, the rotary snow blowing tool having a frame ( 122 ;  122 ′;  122 ″;  222 ;  322 ) forming an auger housing, where the auger housing includes: first and second spaced apart side plates ( 240 ;  242 ;  340 ;  342 ) on outer sides of the auger housing; at least one laterally extending section ( 244 ;  246 ;  248 ;  344 ;  348 ) between the first and second spaced apart side plates; and an aperture ( 262 ;  264 ;  362 ;  364 ) formed in the at least one laterally extending section to provide an operator of the power machine with visibility, through the aperture, of an implement workspace. 
     Implementations may include one or more of the following features. The snow blower implement where the at least one laterally extending section, in which the aperture is formed, is a top wall of the auger housing. The snow blower implement where the at least one laterally extending section, in which the aperture is formed, is a sloped back wall of the auger housing. The snow blower implement where the aperture includes a first group of apertures arranged in a pattern. The snow blower implement where the aperture includes a second group of apertures arranged in a pattern, each of the first and second groups of apertures formed on different sides of the at least one laterally extending section. 
     Another general aspect includes an implement ( 100 ;  100 ′;  100 ″;  200 ;  300 ;  400 ) configured to be coupled to an implement interface ( 40 ) of a power machine ( 10 ), the implement including: a power machine interface ( 110 ;  110 ′;  110 ″;  210 ;  310 ;  410 ) having a machine mount ( 112 ;  112 ′;  112 ″;  212 ;  312 ;  412 ) configured to engage the implement interface of the power machine; and a tool ( 120 ;  120 ′;  120 ″;  220 ;  320 ;  400 ) coupled to the power machine interface, the tool having a frame ( 122 ;  122 ′;  122 ″;  222 ;  322 ;  422 ) forming a housing, where the housing includes at least one group of apertures ( 262 ;  264 ;  362 ;  364 ;  462 ;  464 ;  466 ;  468 ) formed in the housing configured and arranged to provide an operator of the power machine with visibility, through the at least one group of apertures, of an implement workspace while operating the power machine. 
     Implementations may include one or more of the following features. The implement where the housing includes first and second spaced apart side plates ( 240 ;  242 ;  340 ;  342 ;  440 ;  442 ) on outer sides of the implement, and at least one laterally extending section ( 244 ;  246 ;  248 ;  344 ;  348 ;  444 ;  446 ) between the first and second spaced apart side plates, where the at least one group of apertures is formed in the at least one laterally extending section. The implement where the at least one laterally extending section includes a curved back wall ( 344 ) and where the at least one group of apertures is formed in the curved back wall. 
     Another general aspect includes an implement ( 100 ;  100 ′;  100 ″;  200 ;  300 ;  400 ) configured to be coupled to an implement interface ( 40 ) of a power machine ( 10 ), the implement including: a power machine interface ( 110 ;  110 ′;  110 ″;  210 ;  310 ;  410 ) having a machine mount ( 112 ;  112 ′;  112 ″;  212 ;  312 ;  412 ) configured to engage the implement interface of the power machine; a tool ( 120 ;  120 ′;  120 ″;  220 ;  320 ;  400 ) coupled to the power machine interface, the tool including: a frame ( 122 ;  122 ′;  122 ″;  222 ;  322 ;  422 ) forming a housing; an actuator ( 252 ) configured to perform a work function; and at least one aperture ( 262 ;  264 ;  362 ;  364 ;  462 ;  464 ;  466 ;  468 ) formed in the housing and configured and arranged to provide an operator of the power machine with visibility, through the at least one aperture, of an implement workspace while operating the power machine. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1-3  are each block diagrams illustrating functional systems of a representative implement on which embodiments of the present disclosure can be practiced and a power machine to which the representative implement can be coupled. 
         FIG. 4  is a diagrammatic perspective view of an implement including a snow blower having an auger housing that provides improved visibility for an operator of a power machine in accordance with exemplary embodiments. 
         FIG. 5  is a diagrammatic perspective view of another implement including a snow blower having an auger housing that provides improved visibility for an operator of a power machine in accordance with an alternate embodiment. 
         FIG. 6  is a diagrammatic perspective view of a bucket implement having a housing that provides improved visibility for an operator of a power machine in accordance with another exemplary embodiment. 
         FIGS. 7-1 through 7-3  are diagrammatic illustrations of example aperture shapes and orientations in accordance with disclosed embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     The concepts disclosed in this discussion are described and illustrated with reference to exemplary embodiments. These concepts, however, are not limited in their application to the details of construction and the arrangement of components in the illustrative embodiments and are capable of being practiced or being carried out in various other ways. The terminology in this document is used for the purpose of description and should not be regarded as limiting. Words such as “including,” “comprising,” and “having” and variations thereof as used herein are meant to encompass the items listed thereafter, equivalents thereof, as well as additional items. 
     Disclosed concepts are used to increase visibility of the area in front of the housing of an implement, such as in front of an auger housing of a snow blower implement or in front of a bucket implement, to reduce contact with obstacles, structures or other materials which could damage the snow blower and/or the contacted structures or materials. In accordance with disclosed concepts, one or more apertures are formed in a top wall of an auger housing in a pattern which enhances visibility of the area in front of the auger housing. Power machine  10  includes an operator station that includes an operating position from which an operator can control operation of the power machine. In some power machines, the operator station  150  is defined by an enclosed or partially enclosed cab, though this need not be the case in all embodiments. An implement workspace includes an area in front of, or even within, the housing or frame of the implement where the implement engages material such as snow or dirt to perform a work function such as digging, loading, or gathering snow in an auger. Disclosed embodiments include at least one aperture, and in some embodiments, groups of apertures, formed in a housing of a tool of the implement to provide an operator of the power machine positioned in the operator station with visibility, through the aperture, of the implement workspace. 
     Disclosed concepts can be practiced on various implements and various power machines, as will be described below. Representative implements  100 ,  100 ′,  100 ″ on which the embodiments can be practiced and representative power machines  10  and  10 ′ to which the implement can be operably coupled are illustrated in diagram form in  FIGS. 1-3  and described below before any embodiments are disclosed. For the sake of brevity, only one implement and power machine combination is discussed in detail. However, as mentioned above, the embodiments below can be practiced on any of a number of implements and these various implements can be operably coupled to a variety of different power machines. Power machines, for the purposes of this discussion, include a frame, in some instances at least one work element, and a power source that is capable of providing power to the work element to accomplish a work task. One type of power machine is a self-propelled work vehicle. Self-propelled work vehicles are a class of power machines that include a frame, work element, and a power source that is capable of providing power to the work element. At least one of the work elements is a motive system for moving the power machine under power. 
     Referring now to  FIG. 1 , a block diagram illustrates basic systems of power machine  10  as are relevant to interact with implement  100  as well as basic features of implement  100 , which represents an implement upon which the embodiments discussed below can be advantageously incorporated. At their most basic level, power machines for the purposes of this discussion include a frame  20 , a power source  25 , a work element  30 , and, as shown in  FIG. 1 , an implement interface  40 . On power machines such as loaders and excavators and other similar work vehicles, implement interface  40  includes an implement carrier  50  and a power port  60 . The implement carrier  50  is typically rotatably attached to a lift arm or another work element and is capable of being secured to the implement. The power port  60  provides a connection for the implement  100  to provide power from the power source to the implement. Power source  25  represents one or more sources of power that are generated on power machine  10 . This can include either or both of pressurized fluid and electrical power. 
     The implement  100 , which is sometimes known as an attachment or an attachable implement, has a power machine interface  110  and a tool  120 , which is coupled to the power machine interface  110 . The power machine interface  110  illustratively includes a machine mount  112  and a power port  114  for coupling with power machine  10 . Machine mount  112  can be any structure capable of being coupled to the implement interface  40  of power machine  10 . Power port  114 , in some embodiments, includes hydraulic and/or electrical couplers. Power port  114  can also include a wireless electrical connection, as may be applicable on a given implement. While both machine mount  112  and power port  114  are shown, some implements may have only one or the other as part of their power machine interface  110 . Other implements, such as a bucket and some simple forklifts, would not have a power port  114  at all (e.g., See  FIG. 3 ). Some other forklifts may have an actuator for adjusting its tines vertically, horizontally, rotationally, or by extending them in response to power signals received from the power machine  10  at power port  114 . 
     In instances where a power machine has a specific implement carrier, the machine mount  112  will include a structure that complements the specific implement carrier. For power machines without an implement carrier, the machine mount includes features to directly mount the implement  100  to the power machine  10  such as bushings to accept pins for mounting the implement to a lift arm and an actuator for moving the implement. 
     For the purposes of this discussion, implements can be categorized as simple or complex. A simple implement has no actuated work element. One example of a simple implement is a bucket or a forklift without actuable tines. A complex implement has at least one actuable work element such as a forklift with actuable tines. Complex implements are further divided into those that have one actuable work element and those that have multiple work elements. Some complex implements include features of a simple implement. 
     In  FIG. 1 , the implement  100  illustrates a tool  120  for a complex implement with a single work element  124 . The tool  120  includes a frame  122 , which is coupled with or integral to the machine mount  112 . A work element  124  is coupled to the frame  122  and is moveable in some way (vertical, horizontal, rotation, extension, etc.) with respect to the frame. An actuator  126  is mounted to the frame  122  and the work element  124  and is actuable under power to move the work element with respect to the frame. Power is provided to the actuator  126  via the power machine. Power is selectively provided in the form of pressurized hydraulic fluid (or other power source) directly from the power machine  10  to the actuator  126  via power ports  60  and  114 . 
       FIG. 2  illustrates an implement  100 ′, which depicts a complex, multi-function implement. The features in  FIG. 2  that are similarly numbered to those in  FIG. 1  are substantially similar and are not discussed again here for the sake of brevity. Implement  100 ′ has one or more additional work elements  124 ″, which are shown in block form. Each work element  124 ″ has a corresponding actuator  126 ″ coupled thereto for controlling movement of the work element  124 ″. A control system  130  receives power from the power machine and selectively provides power to the actuators  126 ′ and  126 ″ in response to signals from operator inputs. The control system  130  includes a controller  132 , which is configured to receive electrical signals from the power machine  10  indicative of operator input manipulation and control power to the various actuators based on those electrical signals. The controller  132  can provide electrical signals to some or all of the actuators  126 ′ and  126 ″ to control their function. Alternatively, the controller  132  can control optional valve  134 , which in turn controls actuation of some or all of the actuators  126 ′ and  126 ″ by providing pressurized hydraulic fluid to the actuators. 
     Although not shown in  FIG. 2 , in some instances, controller  132  can receive signals indicative of operator actuation of user inputs that are mounted on the implement, as opposed to the power machine. In these applications, the implement is controlled from an operator position that is located remotely from the power machine (i.e. next to the implement  100 ′). 
       FIG. 3  illustrates an implement  100 ″, which depicts a simple implement. The features in  FIG. 3  that are similarly numbered to those in  FIG. 1  are substantially similar and are not discussed again here for the sake of brevity. Implement  100 ″ has one or more engagement structures  126 ″ that is fixedly or moveably attached to the frame  122 ″. Unlike a work element, which is powered by an actuator to move relative to the frame to perform a work function, the engagement structure can engage a medium to perform, in combination with the power machine, work. For example, a simple bucket has an engagement structure including a cutting edge and a defined volume that holds soil or material that is collected into a bucket. As another example, tines of a forklift can be mounted to the frame of the forklift implement for engaging a pallet. Such tines can be adjustable, but in many cases, the tines themselves are not moveable under power to perform work, but are instead engagement structures for engaging and supporting a load to be lifted and/or carried. 
     A power machine interface can include a machine mount in the form of a generally planar interface plate that is capable of being coupled to an implement carrier on a loader. In embodiments, various types of machine mounts can be employed. The power machine interface can also include a power port (e.g., see interfaces  110  and  110 ′ of  FIGS. 1 and 2  respectively), or not such as with the power machine interface  110 ″ of  FIG. 3 . When the power machine interface includes a power port, the power port can include hydraulic conduits that are connectable to conduits on a power machine so that pressurized hydraulic fluid can be selectively provided to an actuator on the implement to actuate a connected working element. The power port can also include an electrical connection, which can be connectable to a controller (such as controller  132  of  FIG. 2 ) and actuators on a valve (such as valve  134 ). The controller and valve can be included in a control system (such as control system  130 ) on the implement for controlling functions thereon. 
     Referring now to  FIG. 4 , shown is an implement  200 , which can be in accordance with, and include features of, the implements illustrated in  FIGS. 1-3 . In the illustrated embodiment, implement  200  is a snow blower implement configured to be attached to a power machine  10 , such as a loader. Implement  200  includes a power machine interface  210  having a machine mount  212 , which can be any structure configured to be coupled to an implement interface (e.g., implement interface  40  discussed above) of a power machine. Power ports, such as port  114  discussed above, can be included on power machine interface  210  and can include hydraulic and/or electrical couplers. While implement  200  includes a power port in exemplary embodiments, the power port is omitted from  FIG. 4  to simplify the illustration of other features. 
     The tool  220  of snow blower  200  is, in exemplary embodiments, a rotary snow blowing tool. Tool  220  includes a frame or auger housing  222  that is attached to machine mount  212  by rear frame supports  230 . Auger housing  222  includes spaced apart side plates  240  and  242  on the outer sides of the implement  200 . Housing  222  also includes a rear wall  244  and a top wall  246  extending angularly between the side plates  240  and  242 . A bottom plate, represented generally at  248 , also extends between the side plates  240  and  242  and functions to scrape or scoop snow into the housing. The top wall  246  has a ridge  250  at its upper and forward edge. 
     Implement  200  includes an auger or rotor, represented generally at  252  but not specifically illustrated in  FIG. 4 , at its forward end. The auger is mounted between the side plates  240  and  242 . The auger is rotated through the use of a hydraulic or other motor (such as an actuator  126  or  126 ′ shown in  FIGS. 1-2 ) which is not illustrated in  FIG. 4 . A separate motor (such as an actuator  126  or  126 ′ shown in  FIGS. 1-2  but not shown in  FIG. 4 ) drives an impeller or rotor  254 . The impeller  254  is a conventional rotating fan type wheel unit that will receive snow from the auger  252 , and will drive the snow upwardly through a discharge chute opening  260  and into a discharge chute. The discharge chute is omitted from  FIG. 4  to better illustrate features of disclosed embodiments as discussed below. 
     To allow an operator of the power machine to have visibility of material, structures or obstacles approaching or entering the auger housing  222 , implement  200  includes one or more apertures or groups of apertures  262  and  264  formed in a laterally extending section between endpoints such as side plates  240  and  242 . The one or more apertures can be formed for example, in rear wall  244  or top wall  246  in a pattern or arrangement to provide visibility through the top wall, while minimizing the likelihood that snow, rocks or other material can pass through the apertures. While the apertures are formed in the top wall  246 , in some embodiments, apertures can be formed into a back wall, or both a back wall and a top wall. Various auger housing shapes in some embodiments may require such configurations of apertures. In the illustrated example embodiment, the apertures  262  and  264  are two series or groups of diagonal slots, with each series formed on a different side of the top wall. In the illustrated embodiment, the diagonal slots in each group are formed parallel to one another, but this need not be the case in all embodiments. The aperture orientation, number, size, and spacing are selected to provide visibility through portions of the top wall, while minimizing the likelihood of material passing through the aperture. In some exemplary embodiments, the slots or other apertures are laser cut into top wall  246 , but in other embodiments they can be formed using any suitable technique. While a series of slots are shown, the exact number of slots or apertures can vary in different embodiments. For example, in some embodiments, a single slot may be formed to define one (or both) of the groups  262  and  264 . Alternatively, in some embodiments, a snow blower may have only one group of apertures. Further, while diagonally oriented parallel slots are shown as an example embodiment, in other embodiments, other shapes and patterns can be used. For example, the groups of apertures  262  and  264  can instead be one or more circular or other shaped apertures that allow for visibility while minimizing material passing through the apertures. The apertures in a group need not be uniform in size, shape, or orientation. 
     Referring now to  FIG. 5 , shown is an implement  300 , which can be in accordance with, and include features of, the implements illustrated in  FIGS. 1-4 . In the illustrated embodiment, implement  300  is a snow blower implement similar to snow blower implement  200  and similarly configured to be attached to a power machine  10 , such as a loader. Implement  300  includes a power machine interface  310  having a machine mount  312 , which can be any structure configured to be coupled to an implement interface (e.g., implement interface  40  discussed above) of a power machine. Power ports, such as port  114  discussed above, can be included on power machine interface  310  and can include hydraulic and/or electrical couplers. While implement  300  includes a power port in exemplary embodiments, the power port is omitted from  FIG. 5  to simplify the illustration of other features. 
     The tool  320  of snow blower implement  300  is, in exemplary embodiments, a rotary snow blowing tool. Tool  320  includes a frame or auger housing  322  that is attached to machine mount  312  by rear frame supports  330 . Auger housing  322  includes spaced apart side plates  340  and  342  on the outer sides of the implement  300 . Housing  322  also includes a rear wall  344  extending between the side plates  340  and  342 . Instead of including a top wall as was the case with implement  200  discussed above, rear wall  344  of implement  300  is curved forward near the top of the housing. A bottom plate, represented generally at  348 , also extends between the side plates  340  and  342  and functions to scrape or scoop snow into the housing. 
     Implement  300  includes an actuator in the form of an auger or rotor, represented generally at  352 . The auger is mounted between the side plates  340  and  342 . The auger is rotated through the use of a hydraulic or other motor (such as an actuator  126  or  126 ′ shown in  FIGS. 1-2 ) which is not illustrated in  FIG. 5 . A separate motor (such as an actuator  126  or  126 ′ shown in  FIGS. 1-2  but not shown in  FIG. 5 ) drives another actuator in the form of impeller or rotor  354 . The impeller  354  is a conventional rotating fan type wheel unit that will receive snow from the auger  352 , and will drive the snow upwardly through a discharge chute opening  360  and into a discharge chute. 
     To allow an operator of the power machine to have visibility of the implement workspace of the auger housing  322 , implement  300  includes one or more apertures or groups of apertures  362  and  364  formed in a laterally extending section between endpoints such as side plates  340  and  342 . The one or more apertures can be formed for example, in rear wall  344  in a pattern or arrangement to provide visibility through the rear wall, while minimizing the likelihood that snow, rocks or other material can pass through the apertures. In the illustrated example embodiment, the apertures  362  and  364  are two series or groups of diagonal slots, with each series formed on a different side of the top wall. In the illustrated embodiment, the diagonal slots in each group are formed parallel to one another, but this need not be the case in all embodiments. The aperture orientation, number, size, and spacing are selected to provide visibility through portions of the rear wall, while minimizing the likelihood of material passing through the apertures. In some exemplary embodiments, the slots or other apertures are laser cut into top wall  346 , but in other embodiments they can be formed using any suitable technique. 
     Referring now to  FIG. 6 , shown is an implement  400  in the form of a bucket. This and other types of buckets, as well as other implements, can include apertures to provide visibility of the implement workspace in accordance with exemplary embodiments. As shown in  FIG. 6 , implement  400  has a frame  422  forming a housing, and includes side plates or walls  440  and  442 , with a laterally extending section in the form of rear wall  444  extending between the side plates. A top wall  446  forms another laterally extending section between side plates  440  and  442 . A bottom plate  448  also extends between the side plates  440  and  442 . Groups of apertures  462 ,  464  and  466  are formed in the rear wall  444  or laterally extending section to provide visibility, to the operator positioned in the operator station, of the implement workspace forward of the rear wall  444 . In this example embodiment, apertures  462  and  464  are positioned at left and right portions of rear wall  444 , outside of machine mount  412  of power machine interface  410  and adjacent the corresponding side plates. Apertures  466  are positioned in middle or central regions of rear wall  444 . In this embodiment, apertures  468  are also formed in top wall  446  to further provide visibility, through the top wall, of the implement workspace. While the various groups of apertures shown in  FIG. 6  are diagonally extending slots, the shape and exact number of apertures can vary in different embodiments. 
     Further, while diagonally oriented slot shaped apertures are shown as an example embodiment, in other embodiments, other shapes and patterns can be used. For example, in various implements, one or more apertures  562 - 1  in the form of ovals can be used as shown in  FIG. 7-1 . In another embodiment as shown in  FIG. 7-2 , one or more vertically oriented rectangular apertures  562 - 2  can be used. In yet another embodiment, one or more horizontally oriented rectangular apertures  562 - 3  can be used as shown in  FIG. 7-3 . Still other shapes of apertures, such as circularly shaped apertures, can be used. The shape, number, orientation, grouping pattern and other features of the apertures can be selected as desired to achieve visibility of the implement workspace. The apertures in a group need not be uniform in size, shape, or orientation. 
     Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.