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You are an expert at summarizing long articles. Proceed to summarize the following text: 
FIELD OF THE INVENTION 
     This invention relates to an end-effector for a robotic mechanism. More particularly, it relates to a scoop or bucket-like attachment for capturing and picking-up friable material, such as soil. It also relates to a versatile end-effector for grasping articles. 
     BACKGROUND TO THE INVENTION 
     In the field of earth moving diggers, diggers have been provided with scooping shovels that have a bucket with a hinged bottom panel. The bottom panel closes up against the edges of the bucket to provide a floor for the bucket. This design was particularly common with steam-powered shovels and is still used in many petroleum-powered earth moving machines. 
     In designs based on a scoop having a shovel/bucket fixed to an arm with the floor panel being hinged, penetration of the scoop into soil has been effected by manipulation of the bucket through the supporting arm. 
     As well, shovel buckets have been attached to a supporting arm by hinged joints, with provision to actuate the bucket itself to perform claw-like functions. In this latter arrangement, the bucket is generally of a monolithic form i.e. the bottom panel and sidewalls are integral. In many configurations the jaws of a pair of such “clam” buckets close together until their teeth abut against each other. 
     In both of the described cases reliance is placed on the weight of the arm to break into material that is to be gathered. In earth-moving equipment, the weight of the arm is substantial and by merely dropping the arm under gravity, sufficient force can be applied to provide a penetrating effect. 
     In robotic applications wherein a vehicle is provided with an arm with a scoop to collect samples of material through remote actuation, the vehicle may not be of significant mass. Similarly, the arm may also be of light-weight. This is particularly true of extra terrestrial exploration vehicles that are necessarily of light weight in a low gravity environment. 
     A need exists for an end-effector arrangement based upon a light weight supporting arm that is nevertheless able to apply adequate disruptive breaking forces to material that is to be collected. Such an end-effector should be versatile in its capacity to gather and contain material being collected while nevertheless being relatively simple in design. As well, it would be desirable to enable such an end-effector to grasp articles that are adapted to be engaged by the end-effector. The present invention addresses these objectives 
     The invention in its general form will first be described, and then its implementation in terms of specific embodiments will be detailed with reference to the drawings following hereafter. These embodiments are intended to demonstrate the principle of the invention, and the manner of its implementation. The invention in its broadest and more specific forms will then be further described, and defined, in each of the individual claims which conclude this Specification. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the invention an end-effector carried by a supporting arm is in the form of a bucket that has an actuated scoop as one portion and a non-actuated plate as a second portion. The scoop lacks an enclosing end wall and is defined instead by its side and circumferential wall only. 
     The plate, which is able to serve as a “floor” for the bucket, is fixed to the arm at some convenient position. The scoop is manipulated by causing it to rotate towards, and preferably around the plate. To achieve this effect, the scoop is hinged to swing in an arcuate path that allows the scoop to be positioned so the plate serves as a “floor”. The scoop may abut the plate, or pass around the plate with a sliding fit. The plate in this latter case serves as a partitioning wall inside a hinged, torus-like scoop segment that may be swung so as to envelop the plate. 
     As a preferred arrangement, the scoop can be arrested at a position whereat the plate serves as a floor portion at one end of the bucket. The scoop may also be arrested at a position wherein the plate is located intermediate the scoop&#39;s front and back edges. Or it may be located at the other end of the scoop. In this manner a bucket cavity may be formed that opens outwardly in either of two, opposed directions. 
     The plate is carried by the arm, generally in a fixed orientation with respect to the arm. In use, the plate may be variously oriented horizontally or vertically by positioning of the arm. In one application the plate may be positioned so that it is substantially aligned with the supporting arm. Both of these components may then be placed in a vertical alignment and pressed into the ground in the manner of a spade. 
     Next, the scoop may first be elevated and then descended in an arc towards the plate. To the extent that material of the surface to be sampled lies above the lower edge of the plate, it will be severed from that surface upon which it lies and contained within the scoop. The scoop may then be closed to capture material which is located adjacent to the plate. Such material, e.g. soil, will then be contained by the circumferential, outer, curved surface of the scoop. The plate also serves to contain material in cooperation within the scoop, preventing it from falling out of the end of the scoop by closing-off one end of the scoop. 
     The plate may be attached to the supporting arm, at a fixed orientation, or its orientation with respect to the arm may be adjustable. It may also be controllable in the sense of being actuated. An adjustable coupling for the plate may be effected through use of a hinged connection to the arm that includes a locking system that will fix the plate at differing, “indexed”, orientations with respect to the arm. In an aligned orientation, the plate and arm can function as a “shovel”. 
     The plate need not be flat. It may be cylindrically curved, for example. The scoop, as well, need not be of circular cross-section. It is sufficient that the edges of the plate fit closely enough to the scoop to provide a containment function when they are interfitted with each other. 
     The plate and scoop may share a common hinge axis. Alternately, the plate may be separately mounted to the arm by supporting means that extends laterally past the hinge of the scoop to connect to the arm. 
     While the plate need not be actuated, it is intended that the circumferentially moving scoop be actuated. The scoop preferably may be swung in an arc about its axis that may extend up to nearly 360° or more. In passing along this curved trajectory, the scoop is able to pass around the plate entirely. By arresting the scoop at appropriate locations with respect to the plate, a bucket cavity can be formed on either side of the plate portion. 
     In more secure operations where spillage is undesirable, a second partitioning panel, providing a second end-wall function to compliment the role of the plate, may be carried by the arm. Such second panel may be both hinged and actuated so as to, when closed on the scoop, form a fully contained cavity within the scoop. With such a cavity so formed, the supporting arm may convey the sampled material without the same orientation restraints that would be present if the bucket were open at one end. This type of arrangement is especially suited to the gathering of contaminating material which should not he dropped during transport. 
     By a further feature of the invention, the scoop and plate may adapted to provide a self-aligning, tool grasping interface allowing the grasping and constraining of articles. This may be effected by providing cooperating notches along the edges of the scoop and/or plate that are positioned to cooperate in engaging with articles that are to be grasped. 
     The foregoing summarizes the principal features of the invention and some of its optional aspects. The invention may be further understood by the description of the preferred embodiments, in conjunction with the drawings, which now follow. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a pictorial perspective view of the end effector of the invention with the plate deployed and the scoop in elevated position. 
     FIG. 1 a  is a cross-sectional view of the scoop and plate of FIG. 1 depicting an axially-mounted motor with an alternate arm-mounted motor and linkages shown in ghost outline. 
     FIG. 2 depicts the arrangement of FIG. 1 with the scoop rotated to enclose the plate portion and the plate respositioned with respect to the arm. 
     FIG. 2 a  is a cross-sectional schematic depiction of the scoop and plate of FIG. 1 showing the plate at various fixed, indexed positions. 
     FIGS. 3 a ,  3   b  and  3   c  are cross-sectional side views of the end-effector progressively acting in front-loading mode, in back-loading mode and in dumping mode. 
     FIG. 3 d  shows the end-effector of FIG. 3 b  with the scoop advanced to provide a slot for controlled release of flowing material. 
     FIGS. 4 a ,  4   b  and  4   c  are progressive cross-sectional side views of the end effector as the scoop is rotated to penetrate vertically into a soil surface. 
     FIGS. 5 a ,  5   b  and  5   c  are cross-sectional side views of the end-effector equipped with a second, hinged and actuated containment panel, progressively depicting the entrapment of contaminating soil. 
     FIGS. 6 a  and  6   b  depict the end effector of FIG. 1 equipped with indentations on the edges of the scoop to enable a shaped article such as a grapple fixture to be grasped. 
     FIG. 7 a  is a cross-sectional view of the scoop and plate portions of the end effector showing the plate with a blunt distal edge. 
     FIGS. 7 b ,  7   c  and  7   d  show progressively enlarged details of optional alternatives to the blunt edge of FIG. 7 a , specifically a sharp edge, an enlarged, beaded edge and a brush-lined edge. 
     FIG. 8 is a pictorial depiction of the end-effector at the end of a support arm mounted on an extra terrestrial lander, with the end-effector delivering (or retrieving) a mobile vehicle located on the surface adjacent the lander. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In FIG. 1 an arm  1  carries a yoke  2  from which extends a plate  3 . While shown as a full “y”-shaped yoke, a half-yoke would suffice. Contained within the yoke  2  is an axial motor  4  which serves to actuate the scoop  5 . The motor  4  may contain a gear assembly  4   a  to provide increased torque. 
     Activation may also be provided from an actuator  27  mounted elsewhere, as on the arm  1 , and connected by rotary and/or chain linkages  28  to the scoop  5 . This is shown in ghost outline in FIG. 1 a , which figure also shows the axially-mounted motor  4  coupled between the yoke  2  and scoop  3 . 
     The scoop  5  has two side panels  6  and a preferably arcuate bottom plate  7 . The edges of these parts may have notches  8  to allow for grasping of objects as further described below. 
     The plate  3  is shown in FIG. 1 as aligned with the arm  1 . This is optional. The plate  3  may be angled with respect to the arm  1 , as shown in FIGS. 2 and 2 a . The alternate orientations of the plate  3  depicted in FIG. 2 a  represent fixed positions to which the plate  3  may be shifted manually or by other means, such as by manipulation of the arm  1  while the plate  3  is engaged with a surface. Engagement means allow the plate  3  to be locked in various orientations. 
     The scoop  5  swings on an arc that allows it to embrace the plate  3 . The outside face of the plate  3  may carry scarifying blades  9  to allow the scoop  5  to loosen material that is crusty. The blades  9  are shown in FIGS. 1 and 3 as sharp, continuous edges, but may be of various forms, e.g. interrupted, sinuous. 
     In FIG. 3 a  the scoop  5  is shown advancing in front-loading mode into an elevated bank of soil  10 . In FIG. 3 b , the scoop  5  is being swung in the reverse direction to enter soil  10  in back-loading mode. In FIG. 3 c , soil obtained as in FIG. 3 b  and carried on the bottom plate  7  is being dumped by the action of causing the scoop  5  to retire. In this FIG. 3 c , the plate  3  scrapes the soil  10  off the bottom as the scoop  5  passes along its retiring arc. 
     Optionally, in FIG. 3 d , the scoop may be swung outwardly to open a gap  19  to more controllably release soil  10  in the gap  19  created between the plate  3  to the outwardly moving scoop bottom plate  7 . The gap  19  with may be widened or narrowed to provide for fast or slow soil release. 
     In FIGS. 4 a ,  4   b  and  4   c  the scoop  5  progressively penetrates a flat surface  11  that, optionally, has first been loosened by the scarifying blades  9 . In FIG. 4 a  the plate  3  is pushed into the soil  10  in the manner of a spade. Once a first amount of soil  10  has been removed, the bottom plate  3  may be inserted in the depression  12  so formed, and the scoop  5  may attack the sides of the depression  12 , as shown in FIG. 4 c.    
     In FIGS. 5 a ,  5   b  and  5   c  an additional containment panel  13  is carried by the arm  1 . This additional panel  13  is both hinged and actuated with respect to the yoke  5 . In FIG. 5 a  the additional panel  13  is elevated to be parked in a standby location. In FIG. 5 b  the scoop  5  has penetrated soil  10 , advancing soil  10  onto the bottom plate  7 . At this stage, the containment panel  13  is commencing to swing downwardly. 
     In FIG. 5 c  a cavity  14  has been formed within the scoop  5  by the bottom plate  7 , the containment panel  13 , the plate  3  and the side panels  6 . Within the cavity  14 , so formed, soil  10  may be carried with greater security against the risk of contaminating the environment. 
     FIG. 6 a  depicts the scoop  5  engaging a shaped grapple fixture  15  using the notches  8  present along the edges of the bottom  7  and side  6  plates. As the scoop  5  closes on the indented arms of the grapple fixture  15 , the fixture  15  will be pressed against the plate  3  and grasped as shown in FIG. 6 b . Conical indentations  19  on the grapple fixture  15  are positioned to self-align and fit precisely with the notches  8  on the scoop  5 . The scoop  5  and/or plate  3  may also carry electrical sockets to engage with connectors associated with the grapple fixture  15 . By this means grasped objects capable of actuation can, in turn, be controlled. 
     The edges of the plate  3  preferably just lie along the surfaces of the scoop  5  as the scoop  5  is rotated. In particular, the distal edge  20  of the plate  3  may be blunt, FIG. 7 a ; sharpened  21 , FIG. 7 b ; enlarged or beaded  22 , FIG. 7 c ; or it may be compliant and flexible as when lined with a brush  23 , FIG. 7 c.    
     While the end-effector of the invention is inherently suited for use on a light vehicle, it may be operated from a solid platform, such as the extra terrestrial lander  24  of FIG.  8 . Actuators  25  on the arm  1  may position the scoop  5  and plate  3  for transfer of soil  10  from the surface  26  to the lander  24 . A trench  27  on the surface  23  which has previously been excavated by the end-effector of the invention is shown in this FIG.  8 . FIG. 8 also depicts the end-effector seizing a mobile vehicle  28  by a grapple fixture  15  to place it at a desired location on the surface  26 . 
     Thus, a versatile and light-weight end-effector may be provided which can serve both to gather and deliver friable material, and to grasp suitably shaped articles for reliable remote manipulation. 
     CONCLUSION 
     The foregoing has constituted a description of specific embodiments showing how the invention may be applied and put into use. These embodiments are only exemplary. The invention in its broadest, and more specific aspects, is further described and defined in the claims which now follow. 
     These claims, and the language used therein, are to be understood in terms of the variants of the invention which have been described. They are not to be restricted to such variants, but are to be read as covering the full scope of the invention as is implicit within the invention and the disclosure that has been provided herein.

Summary:
An end-effector comprises a circulating scoop that cooperates with a plate that lies in its arcuate path. The plate spans the arcuate gap present within the scoop and preferably may be contained within that gap. The plate may be positioned to provide a bucket-like cavity facing in either fore or aft directions. The scoop and/or plate can carry indentations whereby they grasp shaped articles for controlled manipulation.