Patent Publication Number: US-9896811-B2

Title: Apparatus for removing unwanted material from the ground

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a National Stage of International Application No. PCT/EP2012/054740 filed Mar. 16, 2012, the contents of all of which are incorporated herein by reference in their entirety. 
     TECHNICAL FIELD 
     This invention relates to apparatuses such as snowploughs for removing unwanted material from the ground. 
     BACKGROUND ART 
     Snowploughs can be single-purpose integral machines, having a plough permanently mounted on a vehicle with an engine, designed specifically for the purpose of clearing snow and ice from a roadway or other surface. Alternatively, a snowplough may be provided as an add-on or accessory which is to be mounted on a general purpose vehicle such as a truck or tractor or a multipurpose implement carrier. 
     When a snowplough is provided as an accessory, it is typically mounted to the front of the vehicle, but sometimes to the rear. Some ploughs are designed to be slanted permanently to the near-side of the vehicle (i.e. closest to the kerb in normal traffic flow), so that in use, snow is displaced towards the kerb. Other ploughs are designed to be more versatile, with the slant angle being variable or switchable, so that the plough can displace snow and ice sideways either to the left or right, this being also useful in open spaces with no kerbs. 
     The simplest way of achieving this is to mount the plough on a pivot, so that the blade of the plough can be swung to one side or the other. In other words, the right side edge of the blade can be advanced ahead of the left when the plough is swung in the counter-clockwise direction (when viewed from above) or the left side edge can be advanced ahead of the right when the plough is swung clockwise. In the former configuration, as the plough is driven forward, it displaces snow to the left, and in the latter configuration to the right. For ease of reference the former configuration will be described herein as a left-displacing plough and the latter as a right-displacing plough. 
     A disadvantage of this simple arrangement is that the pivoting action of the plough, as it swings relative to the vehicle, also results in lateral displacement of the plough. Thus, the leading edge will move laterally across the straight-ahead line of travel of the vehicle in the same direction as the displacement direction of the snow, i.e. the leading right-hand edge moves left when the plough is left-displacing and right when the plough is right-displacing. 
       FIG. 1  shows such a plough  10  mounted on the front  12  of a vehicle having a body  14  and wheels, of which only the left front wheel  16  and right front wheel  18  are shown. (As the vehicle&#39;s direction of travel is down the page, the left and right are reversed in this view). The connection between the vehicle mounting  20  and the plough body  22  takes the form of two triangular plates  24 ,  26  pivoted together about a pivot point  28 . 
     A plough blade  30  at the front of the plough body  22  clears a path when the plough is lowered and driven forward over the ground in a direction of forward travel  32 . The cleared path is defined between a pair of parallel dot-dash lines  34 ,  36  defined by the path of the right and left edges respectively of the plough in the direction of travel. The tracks of the left and right wheels are shown by dashed lines  38 ,  40  (for the left wheel  16 ) and  42 ,  44  (for the right wheel  18 ). It can be seen that the wheel tracks lie within the ploughed area, giving the vehicle traction in adverse conditions. 
     Also seen in  FIG. 1  are a pair of castors  46  (which could be replaced by slides) on which the plough body is additionally supported. Not visible in  FIG. 1 , but of relevance, is a rotatable cylindrical brush which is mounted within the plough body  22  with its axis (indicated by a broken line  48 ) parallel to and behind the blade  30  of the plough. The plough blade can be selectively raised and the brush lowered to the ground, and the brush rotated so that it can sweep remaining snow on e.g. a second pass over the ploughed ground, or when used over other debris or snow which is not so deep as to require the snowplough. Alternatively the blade can be lowered to contact the ground, raising the brush during ploughing. The operation and raising and lowering of the brush and plough can be independently controlled, or can be linked to a common selection control. 
       FIG. 2  shows the same plough in use, when slanted in a counter-clockwise direction when viewed from above. In other words, the plough is in a left-displacing configuration. The right-displacing configuration is a mirror image. 
     Now it can be seen that the pivoting of the plough body  22  about the pivot point  28  results in the lateral displacement or translation of the plough body and in particular the blade  30  across the direction of travel. The result is that the cleared path  34 ,  36  is no longer aligned with the vehicle, and the right wheel track  42 ,  44  is no longer within the cleared path&#39;s right-hand edge  34 , and the effective width of the vehicle has increased. Even if the plough is much wider than the vehicle so that the vehicle remains within the ploughed path, the arrangement involves a considerable swinging of the plough from one side to another as the angle changes. 
     One solution is to make the plough wide enough that it will extend to cover the tracks of both wheels, regardless of its orientation. However, this results in a plough and vehicle which is significantly less manoeuvrable, especially in narrow spaces, such as along pathways or between aeroplanes at an airport. 
     DISCLOSURE OF THE INVENTION 
     There is provided an apparatus for removing unwanted material from the ground when the apparatus is driven across the ground by the vehicle, the apparatus comprising:
         a) a vehicle mounting permitting attachment of the apparatus to a vehicle;   b) a body supporting a path-clearing blade, the blade having a longitudinal axis generally parallel to the ground in use, defining an axis of the body; and   c) a jointed connection between the vehicle mount and the body permitting the axis of the body to rotate within a plane generally parallel to the ground in use, the jointed connection comprising at least one pivot arm which pivots in a counter-clockwise sense relative to the vehicle mount as the body&#39;s axis rotates in the clockwise sense, and vice versa.       

     The counter-rotation of the pivot arm relative to the direction of rotation of the body&#39;s axis serves to translate the body in a direction which counteracts the natural swinging movement due to pivotal rotation of the body about the axis. 
     Preferably, the jointed connection comprises:
         i. a first pivot arm pivotally connected about a first proximal axis of rotation relative to the vehicle mounting and pivotally connected about a first distal axis of rotation relative to the body, and   ii. a second pivot arm pivotally connected about a second proximal axis of rotation relative to the vehicle mounting and pivotally connected about a second distal axis of rotation relative to the body, wherein as the body&#39;s axis rotates in the clockwise sense relative to the ground, the first and second arms each pivot in a counter-clockwise sense about their respective proximal axes of rotation, and vice versa.       

     Thus, in comparison to a body mounted on a simple pivot arm, which swings laterally away from the neutral position when rotated to a slanted angle, the jointed connection of the invention permits the body to adopt a slanted orientation without significant lateral displacement. 
     Preferably, one of the pivot arms is a load-bearing arm, and the other is a link arm which is not load-bearing but which constrains the movement of the body. 
     Preferably, the separation between the first and second proximal axes of rotation is greater than the separation between the first and second distal axes of rotation. 
     Thus, the four axes of rotation define the vertices of a quadrilateral, with the first and second pivot arms defining two of the opposed sides of the quadrilateral, where the quadrilateral tapers from the mounting end towards the body end. 
     (For the avoidance of doubt the quadrilateral may be regular or irregular. Irregular quadrilaterals are of the type known as a trapezium in North America and a trapezoid in the UK and Ireland, where no two sides are parallel. Regular quadrilaterals have the opposite names trapezoid in North America and trapezium in the UK and Ireland and are distinguished by at least two sides being parallel.) 
     Most preferably, the geometry of the arms and the axes of rotation is selected to constrain the body to always be centred on approximately the same line, this being the centreline of travel of the vehicle. 
     The body can also be constrained, by the jointed connection to lie within substantially the same width, regardless of the angle of rotation adopted by the body. By “substantially the same width” it is meant that the lateral extremities of the body when rotated away from the neutral position do not stray by more than a threshold amount on either side outside the body&#39;s lateral extent when it is in the neutral position. 
     The threshold amount can be defined in terms of the width of the plough itself or the width of the vehicle. Preferably, the threshold amount is not more than 12.5% of the plough blade&#39;s width, more preferably not more than 10%. In particularly preferred embodiments the threshold amount is not more than about 8% and most especially not more than 6%. For example, one embodiment confines the lateral movement of a 1500 mm wide blade to move no more than 120 mm outside the neutral path of the blade on either side, and a currently preferred embodiment confines the lateral movement to 85 mm respectively giving threshold amounts of 8% and 5.6%. The arrangements described herein can be modified to confine the blade entirely within its neutral position width for all angles of operation. In this way, the body can be rotated through a range of angles, preferably to both sides, without significant lateral translation. Where the width of the body of the apparatus is approximately equal to the width of the vehicle body (or of the wheelbase track width) then the body will continue to clear the same track (adjusted for the slight narrowing due to the offset of the blade, i.e. the cos α factor. 
     Preferably, the blade can be rotated to either side through an angle of at least 20 degrees relative to a neutral position, more preferably at least 25 degrees, and most preferably 28-33 degrees. For a snow plough this angular offset allows efficient clearing of snow, ice and other debris. 
     The first and second pivot arms are preferably rigid. 
     While compound (articulated) arms may be employed, the simplest and presently preferred form is a rigid, simple arm in each case extending from the respective proximal axis to the distal axis of rotation. 
     Preferably, the apparatus further comprises a driven means for moving the body relative to the mounting. 
     The driven means is preferably selected from a hydraulic, pneumatic or mechanical mechanism. 
     The apparatus may optionally comprise a power source, or it may comprise a coupling to a suitable power source for driving the driven means. 
     Most preferably, the driven means is a hydraulic cylinder operable to vary the rotation angle of the body relative to the mounting as it is extended and contracted. 
     In a preferred embodiment, the apparatus is embodied in a snow plough. 
     More preferably, the apparatus further comprises a rotatable brush disposed on the body. 
     The brush is preferably disposed behind the plough blade. 
     Preferably the vertical height of the blade can be varied relative to the brush to selectively bring either the brush or blade into proximity or contact with the ground. 
     Preferably, at least one and preferably both of the distal axes of rotation are disposed forwardly of the rear edge of the brush in the direction of the blade. 
     More preferably, at least one and preferably both of the distal axes of rotation are disposed forwardly of the axis of the rotatable brush in the direction of the blade. 
     In another aspect, the invention provides a snowplough accessory for mounting on a vehicle, comprising:
         a) a body supporting a snowplough blade at a front side thereof, the blade having a longitudinal axis generally parallel to the ground in use, defining an axis of the body;   b) a rotatable cylindrical brush mounted on the body rearwardly of the snowplough blade with its axis parallel to the axis of the body;   c) a vehicle mounting permitting attachment of the apparatus to a vehicle;   d) a pivoting connection between the vehicle mount and the body permitting the axis of the body to rotate within a plane generally parallel to the ground in use;   wherein the pivoting connection comprises an arm which extends from the vehicle mount to a pivot point on the body, the pivot point being located above or forward of the brush, and the arm extending to the pivot point over the top of the brush such that in normal use the brush is located below the arm and above the ground.       

     Preferably, the pivot point is located above or forward of the axis of rotation of the brush. 
     Typical known snowplough accessories of this kind (i.e. combined snowplough and brush) have a plough blade carried forwardly of a rotatable brush, both mounted in a body or housing. The housing is mounted on the vehicle by a connection arrangement (see for example the plates  24 ,  26  and pivot  28  in  FIG. 1 ) which is carried on the body rearwardly of the brush. 
     A pivot arm which extends over the top of the brush to a pivot point on the body which is carried above or forwardly of at least the rear edge of the brush and more preferably above or forwardly of the axis of the brush provides a significant advantage in that the accessory is more compact, and any tendency to lateral swinging is significantly reduced. 
     The preferred features of the first aspect of the invention enumerated earlier and in the dependent claims are equally applicable to the second independent aspect of the invention but not separately enumerated here for conciseness. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic overhead view of a known snowplough connected to the front of a vehicle body, when in a neutral (straight-ahead) position; 
         FIG. 2  is a schematic view of the known snowplough of  FIG. 1 , when slanted to the left-displacing configuration; 
         FIG. 3  is a perspective view of an apparatus according to the invention, in perspective view from behind and below; 
         FIG. 4  is a perspective view of the apparatus of  FIG. 3 , in perspective view from behind and above; 
         FIG. 5  is a perspective view of the apparatus of  FIG. 3 , in perspective view from in front and below; 
         FIG. 6  is a perspective view of the apparatus of  FIG. 3 , in perspective view from in front and above; 
         FIG. 7  is a top plan view of the apparatus of  FIG. 3 , when attached to the front of a vehicle and when in a neutral position; 
         FIG. 8  is a top plan view, similar to  FIG. 7 , with the apparatus in a left-displacing configuration; 
         FIG. 9  is a top plan view, similar to  FIG. 7 , with the apparatus in a right-displacing configuration; 
         FIG. 10  is a side elevation of the apparatus of  FIG. 7 , shown from the vehicle&#39;s left-hand side is a top plan view, similar to  FIG. 7 , with the apparatus in a left-displacing configuration; 
         FIG. 11  is a side elevation of the apparatus of  FIG. 7 , shown from the vehicle&#39;s right-hand side is a top plan view, similar to  FIG. 7 , with the apparatus in a right-displacing configuration; 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring to  FIGS. 3-6 , an apparatus  50  according to the invention is shown from different perspective viewpoints. The apparatus  50  comprises a snowplough body  52  having a snowplough blade  54  mounted at the front end  56  thereof, and a cylindrical roller brush  58  mounted with its major longitudinal axis parallel to the axis of the blade  54  at a position intermediate the blade and the rear end  60  of the apparatus  50 . 
     The blade is carried at either side on a swivel arrangement  62  which permits it to be raised and lowered (by hydraulic control  64 ) relative to the body  52 . A spring  66  biases the front breakaway edge of the plough into its normal working position, but allows the bottom edge to breakaway by pivoting up and back when a hard obstruction is struck, in known manner. 
     A pair of rear castor wheels  68  support the rear end  60  of the apparatus on the ground, so that the combined load of the body, plough and brush is primarily supported by the castors  68  and the pivot arm  74  (described below). The same unit could be fully supported on a load-bearing pivot arm from the front of a tractor without any castors, slides or other ground-engaging support. 
     The blade height when in the lowered position can be controlled, and is adjustable to give the required clearance over the surface being ploughed, with typical adjustments being 0-20 mm above the ground surface 
     The brush  58  can be lowered to the ground under air pressure when the blade is raised, to contact the ground and sweep the ground by rotation of the brush, again in known manner. 
     Rearward of the body  52  is a vehicle mounting  70  which could take many forms but in the illustrated embodiment is in the form of a plate having a recess  72  which is adapted to receive a complementary mounting structure (not shown) provided on a vehicle. The form of the vehicle mounting shown is proprietary but can be varied to suit any particular vehicle&#39;s pick-up and mounting system. 
     The vehicle mounting is connected to the apparatus body by a jointed connection in the form of a first pivot arm  74  and a second pivot arm  76 , which will be described now in further detail with reference to  FIG. 7 . 
     In  FIG. 7 , the apparatus  50  is shown mounted on a vehicle the front of which  78  is illustrated. One can see in  FIG. 7  the left front wheel  80 , right front wheel  82 , front headlights  84  and a proprietary pick-up and mounting structure  86  which engages with the vehicle mounting  70  of the apparatus  50 . Lock bolts  88  project inwardly into receiving holes  90  ( FIG. 4 ) provided in the vehicle mounting to secure the apparatus on the mounting structure  86  of the vehicle  78 . 
     The apparatus  50  is shown in  FIG. 7  in a neutral position, i.e. with the axis defined by the blade, shown as A-A transverse to the straight-ahead direction of travel of the vehicle. The first pivot arm  74 , which is connected at a first proximal axis of rotation  92  to the vehicle mounting and at a first distal axis of rotation  94  to the body  52 , is parallel to the direction of travel of the vehicle. This is a load-bearing arm and can be thought of as taking the place of a primary pivot arm in a conventional arrangement. 
     The second pivot arm  76  is connected which is connected at a second proximal axis of rotation  96  to the vehicle mounting, and at a second distal axis of rotation  98  to the body  52 . This arm  76  is not load-bearing but acts as a link arm constraining the movement of the body. The second pivot arm  76  is arranged to converge towards the first pivot arm as it approaches the apparatus body  52 . 
     The four axes of rotation  92 ,  94 ,  96 ,  98  define the vertices of an irregular quadrilateral, with the first and second pivot arms  74 ,  76  defining two of the opposed sides of the quadrilateral, where the quadrilateral tapers from the mounting end  92 ,  96  towards the body end  94 ,  98 . 
     The body can be rotated clockwise or counter-clockwise from the position shown in  FIG. 7  by the action of a hydraulic cylinder  100  which, in the embodiment shown extends from approximately the middle of the first pivot arm to a pivot point  102  located on the top of the body. It will be appreciated that other motive mechanisms may be used such as electrical motors, pneumatic mechanisms, geared arrangements driven by a power take-off from the body, or any other suitable means for applying a rotating force. Also, where an extending cylinder arrangement such as the hydraulic cylinder  100  is used, this may be provided between alternative connection points, e.g. between either arm  74 ,  76  and either of the body  52  and mounting  70 , or directly between the mounting  70  and body  52 . 
     Referring next to  FIG. 8 , the apparatus is shown having been rotated counter-clockwise (as viewed from above), i.e. to a left-displacing position. This has been achieved by contracting the cylinder  100  to draw the cylinder&#39;s pivot point  102  closer to the first pivot arm  74 . The distances between each adjacent pair of the four vertices, i.e. the distances  92 - 94 ,  94 - 98 ,  98 - 96 , and  96 - 92 , are fixed in length but the internal angles at each vertex are variable. The angles at vertices  94  and  96  have opened up and those at vertices  92  and  98  have become more acute. 
     The result is that the first and second pivot arms  74 ,  76  have each pivoted about their respective proximal axes of rotation  92 ,  96  in a clockwise rotation as the body  52  and its axis A-A has rotated in a counter-clockwise direction relative to the vehicle mounting  70 . As a consequence the distal axes of rotation have moved laterally towards the vehicle&#39;s right (relative to  FIG. 7 ), and this has pulled the entire body sideways, offsetting the normal lateral movement which would result from a conventional rear-mounted pivot as shown in  FIGS. 1 and 2 . It can thus be seen that the path which will be ploughed, defined by the rearward projection or track between the outermost edges  104 ,  106  of the plough blade, continues to coincide with the tracks of the wheels  80 ,  82 . 
       FIG. 9  shows the body when rotated fully in the opposite direction, i.e. with the cylinder  100  fully extended and the plough in a right-displacing configuration. Now the shape of the quadrilateral  92 ,  94 ,  96 ,  98  has distorted in the opposite manner relative to the  FIG. 7  shape, with the distal axes of rotation (and hence the apparatus body  52 ) shifted to the vehicle&#39;s left, i.e. as the body rotates clockwise, the first and second pivot arms  74 ,  76  rotate counter-clockwise about their proximal axes of rotation  92 ,  98 . 
     It can again be seen that this has the effect of keeping the track defined between the plough blade edges  104 ,  106 , aligned with the track of the wheels  80 ,  82  when the vehicle drives straight ahead. (It is noted that as shown in  FIGS. 8 and 9 , the castors  68  have not rotated to trail along the line of the direction of travel as they would in fact do if the apparatus was driven in contact with the ground.) 
       FIGS. 10 and 11  show the arrangement of  FIG. 7  from either side, i.e. the front of the vehicle  78  with its pick-up and mounting structure  88  in engagement with the apparatus&#39;s vehicle mounting  70 . It can be seen in this view that arm  74  is in two sections  74   a  and  74   b . Section  74   a  extends rearwardly from the first distal axis of rotation or pivot point  94 , over the top of the vehicle body  52 , and section  74   b  connects downwardly at an angle to the first proximal axis of rotation  92  at the vehicle mounting  70 . 
     The second pivot arm, best seen in  FIG. 11 , extends in a straight line, between the second distal axis  96  and second proximal axis  98 , again over the top of the body  52  and above the brush. 
     This has the effect of allowing the distal axes of rotation to be positioned forwardly of the rear of the body and even forwardly of the axis  48  of the brush  58 . In this way, the centre of pivoting of the body, defined by the distal axes of rotation, is at a point which is between the brush axis and the blade, minimising the extent to which the brush and blade swing out to the side when the body is pivoted. 
     When compared with the arrangement in  FIGS. 1 and 2 , the result is that the snowplough and brush can clean the path along which the wheels will travel, without requiring an unduly wide blade. 
     Thus, if the width of the blade, as measured by the distance between the edges  104 ,  106  ( FIGS. 7-9 ), is w, the effective ploughing path, as defined by the rearward projection of those edges ( FIGS. 8 and 9 ) will be w(cos α) where α is the angle of rotation of the axis A-A from its centred position as shown in  FIG. 7 . In  FIGS. 8 and 9 , a is approximately 30 degrees. 
     The geometry of the arrangement, taking into account the depth of the body from front to back, and the compensation against lateral swinging provided by the first and second pivot arms, means that the working width of the vehicle and snowplough accessory is within 85 mm of its mean width (as in  FIG. 7 ) throughout the entire range of angles of rotation moving from  FIG. 8  to  FIG. 7  to  FIG. 9 . 
     Put another way, if one considers that the width of the exemplary snowplough and vehicle in  FIG. 7  is 1500 mm, i.e. with the plough in the neutral position. One could drive this vehicle in a straight line along the centre of a pathway of constant width 1670 mm (i.e. 85 mm more than the neutral working width on either side), while swinging the plough out to one side ( FIG. 8 ) or the other ( FIG. 9 ). This provides a significant advantage when working in tight areas such as along footpaths or among machinery and equipment such as aeroplanes. In contrast, the neutral width of a commercially available (larger) snowplough is 2400 mm, but to accommodate this vehicle in the same manner one would need a path of width 3100 mm, i.e. on each side it swings out by a further 350 mm as it is slanted towards that side as shown in e.g.  FIG. 2 . Since the difference of scale is linear, the comparative percentage figures (i.e. 85 mm as a percentage of 1500 mm, and 350 mm as a percentage of 2400 mm) are 5.6% for the illustrated embodiment of the invention and 14.6% for the conventional snowplough of  FIG. 1 . 
     It is to be understood that the snowplough may be made in many different widths to fit different vehicles and to be used in various environments. No limitation to particular dimensions is in any way implied by the comparison of these different embodiments, which simply illustrate the advantages of employing the claimed invention. 
     The apparatus of  FIGS. 3-11  also includes several hydraulic lines (not shown) for connection to hydraulic feed lines provided from the vehicle (not shown). These hydraulic lines power the apparatus for rotation of the brush, and for raising of the blade. 
     The invention is not limited to the embodiments shown which may be varied or modified without departing from the scope of the invention as defined by the statements of invention herein.