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CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application No. 60/305,979, filed Jul. 16, 2001. This U.S. Provisional Application is herein incorporated by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Excavation bucket assemblies are used in the construction and mining. The bucket assemblies are used with a variety of different excavating apparatuses such as backhoes, power shovels, front-end loaders, dragline equipment, etc. Excavation bucket assemblies typically have a bucket body with a rear wall, sidewalls, and a bottom wall. The walls cooperatively define a region where excavated material can be contained and moved. The bottom, front edge of the bucket body can be coupled to a lip. Tooth assemblies are coupled to the lip to form an excavation bucket assembly. 
     Each tooth assembly can include an adaptor and a tooth. The adaptor can be coupled to the lip and a tooth can be coupled to the adaptor. Pins can be used to couple the parts of the tooth assembly together and can be used to couple the tooth assembly to the lip. When a tooth becomes worn or damaged, the pin coupling the tooth to its corresponding adapter can be removed so that the tooth can be uncoupled from the adaptor. A new tooth is then mounted in the place of the worn or damaged tooth. 
     During the tooth replacement process, the pin is knocked out with a large hammer. If the pin is damaged during this process, it is replaced with a new pin. Frequently replacing broken pins is undesirable as doing so increases the cost of maintaining the excavation bucket assembly. Moreover, using a large hammer to remove a pin can be dangerous. When striking the pin with a hammer, flying debris such as metal chips and sand can be created. The flying debris can potentially harm persons in the vicinity of the hammering. 
     An improvement over the conventional pin-based coupling systems is described in U.S. Pat. No. 6,216,368 by the same inventor as the present invention. FIG. 1 shows an embodiment in the U.S. patent. FIG. 1 shows the wedge-locking system  101  that couples an adaptor  106  and a tooth  105  together without the use of pins. Other details about the wedge-locking system  101  are described in the U.S. patent, which is herein incorporated by reference in its entirety for all purposes. As shown in FIG. 1, the wedge-locking system  101  is present in a depression  102  in the adaptor  106 . In this example, the depression  102  is in the form of a rectangle and is defined by four slightly raised walls. 
     Over a period of time, particles such as grit or sand can get into the depression  102  and can abrade the parts of the wedge-locking system  101  and the adaptor  106 . Accordingly, when the operator uncouples the adaptor  106  and the tooth  105 , the operator also cleans the depression  102  of sand and grit. If the operator does not clean the depression  102  well, particles can remain in the depression  102 . When the wedge-locking system  101  is in use, the particles lodged in the depression  102  can continue to abrade the parts of the wedge-locking system  101  and the adaptor  106 . The abrasion reduces the useful life of the wedge-locking system  101  and the adaptor  106 . More frequent replacement of the wedge-locking system  101  parts and the adaptor  106  may be required. 
     Embodiments of the invention address these and other problems. 
     SUMMARY OF THE INVENTION 
     One embodiment of the invention is directed to a locking system for coupling a first member including an aperture, and a second member having a receiving region, the locking system comprising: (a) an interference element including (i) a first portion that fits within the aperture of the first member when the locking system couples the first member and the second member together, and (ii) a second portion, wherein the first portion forms an angle with respect to the second portion, and (iii) a protrusion that extends into the receiving region of the second member when the locking system is in use; and (b) a locking element that engages the second portion of the interference element when the locking system is in use. 
     Another embodiment of the invention is directed to an assembly comprising: a first member including an aperture; a second member having a receiving region and a recess; and a locking system that couples the first member to the second member, wherein the locking system comprises (a) an interference element including (i) a first portion disposed within the aperture of the first member, (ii) a second portion, wherein the first portion forms an angle with respect to the second portion, and (iii) a protrusion that extends into the receiving region of the second member, and (b) a locking element that engages the second portion of the interference element and that is in the recess. 
     Another embodiment of the invention is directed to an excavation bucket assembly comprising: a bucket body; and a plurality of tooth assemblies coupled to the bucket body, wherein each tooth assembly includes an adaptor including an aperture, a tooth having a receiving region, and a locking system that couples the first member to the second member, wherein the locking system comprises (a) an interference element including (i) a first portion disposed within the aperture of the first member, and (ii) a second portion, wherein the first portion forms an angle with respect to the second portion, and (iii) a protrusion that extends into the receiving region, and (b) a locking element that engages the second portion of the interference element. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a cross-sectional view of a wedge-locking system that is present in a depression in an adaptor. 
     FIG. 2 shows a lip assembly with a plurality of tooth assemblies coupled to a lip. 
     FIG. 3 shows a cross-sectional view of a portion of a lip assembly in a region where a wedge-locking system according to an embodiment of the invention would be used. 
     FIG. 4 shows a cross-sectional view of a portion of a lip assembly in a region where a locking system according to an embodiment of the invention would be used. In this Figure, the tooth has a hole that extends through a leg of the tooth. 
     FIG. 5 shows an interference element according to an embodiment of the invention. 
     FIG. 6 shows a perspective view of an adaptor according to an embodiment of the invention. 
     FIG. 7 shows a perspective view of an adaptor and an interference element according to an embodiment of the invention. 
     FIG. 8 shows a perspective view of a locking element according to an embodiment of the invention. 
     FIG. 9 shows a perspective view of a locking element, an adaptor, and an interference element according to an embodiment of the invention. 
    
    
     DETAILED DESCRIPTION 
     FIG. 2 shows top plan view of a lip assembly according to an embodiment of the invention. The lip assembly includes a lip  20 . A plurality of tooth assemblies  60  is coupled to the lip  20 . Each tooth assembly  60  extends in a forward direction away from the lip  20 . Each tooth assembly  60  includes an adaptor  33  and a tooth  31 . The adaptor  33  and the tooth  31  are coupled together by a wedge-locking system  37 . An adaptor shroud (not shown) may optionally cover the front portion of the adaptor  33 . An interconnection mechanism  29  can couple the adaptor  33  to the lip  20 . The interconnection mechanism  29  can include pins, C-clamps, or even the same or similar type of wedge-locking system that is used to couple the adaptor  33  and the tooth  31  together. Lip shrouds  36  are respectively disposed between adjacent tooth assemblies  60 . The lip shrouds  36  protect the lip  20  from wear. A bucket body (not shown) may be coupled to the rear end of the lip  20  (i.e., on the opposite side as the tooth assemblies  60 ) to form a bucket assembly. The bucket body can be added to the rear end of the lip  20 , and may include a bottom, sidewalls, and a rear wall. Typically, some or all of the parts of the lip assembly are made of a hard metal such as carbon steel. 
     In the example shown in FIG. 2, each adaptor  33  can be considered a first member and each tooth  31  may be considered a second member. Although adaptors and teeth are discussed for purposes of illustration, it is understood that the wedge-locking system  37  can be used to couple any suitable first and second members together. For example, the first and second members need not be parts of a lip assembly or even an excavation bucket assembly. In some embodiments, it is possible to use the wedge-locking system to couple a compaction element for a compactor to a compactor wheel. The compactor may be used, for example, to pack trash in a landfill. 
     FIG. 3 shows a side-cross-sectional view of one embodiment of the invention. In this example, a locking system  37  couples a tooth  31  and an adaptor  33  together. The adaptor  33  is secured to a lip  20 , and includes a recess  75  that is substantially defined by three walls. The three walls include a rear abutment wall  79  and two sidewalls (not shown). A front region of the recess  75  does not have a wall. In this example, the recess  75  can be in the form of a wedge that is defined by two sidewalls, a bottom surface, and a rear abutment wall  79 . 
     An aperture  25  passes through the adaptor  33 . Alternatively, the aperture  25  can pass through only a portion of the adaptor  25 . The tooth  31  may include two legs  31 ( a ),  31 ( b ). One of the legs  31 ( a ) can have a receiving region  30  on its underside. The tooth  31  is coupled to the adaptor  33  using the wedge-locking system  37 . 
     In this example, the wedge-locking system  37  includes an interference element  71 , a locking element  73 , and a biasing element  72 . These three elements  71 ,  72 ,  73  work together to secure the tooth  31  to the adaptor  33 . 
     The interference element  71  can be a single body made of metal. It can include a protrusion  71 ( a ), a first portion  71 ( b ), and a second portion  71 ( c ). In this example, the first portion  71 ( b ) and the second portion  71 ( c ) form an angle. The first portion  71 ( b ) extends into the aperture  25  in the adaptor  33 , while the second portion  71 ( c ) is outside of the aperture  25 . The interference element  71  can move up and down while the walls of the aperture  25  constrain the lateral movement of the interference element  71 . The protrusion  71 ( a ) can fit within and may be cooperatively structured with the receiving region  30  of the tooth  31 . In this example, the receiving region  30  extends through a portion of the leg  31 ( a ). In other examples, the receiving region  30  can form part of a hole that extends from one side of the leg  31 ( a ) to the other side of the leg  31 ( a ). 
     The locking element  73  in this example is in the form of a wedge. It includes an upper surface that is at an angle with respect to a lower surface of the locking element  73 . When the locking element  73  moves forward (e.g., in the direction x), it engages the second portion  71 ( c ) of the interference element  71  and pushes the interference element  71  upward (e.g., in the direction y) until the protrusion  71 ( a ) is received in the receiving region  30  of the tooth  31 . Moving the locking element  73  in a forward lateral direction causes the interference element  71  to move upward in a direction substantially perpendicular to the lateral direction. Once the protrusion  71 ( a ) is in the receiving region  30 , the tooth  31  and the adaptor  33  are coupled together. 
     When the tooth  31  and the adaptor  33  are coupled together, a biasing element  72  can apply pressure to the locking element  73  so that the locking element  73 , the interference element  71 , and the tooth  31  are all engaged. A spring  75  in the biasing element  72  can push a pin  77  into a cooperatively structured slot in the adaptor  33  to secure the biasing element  72  to the adaptor  33 . 
     Variations in the illustrated embodiment are possible. For example, although one specific type of biasing element  72  is shown in FIG. 3, the biasing element could be any other suitable device that can apply pressure to the locking element  73 . For example, the biasing element could be one or two elastomeric blocks that can push the locking element  73  under the second portion  71 ( c ) of the interference element  71 . In yet another embodiment, it is possible to have a bolt or other securing device pass through the biasing element  72  and to the adaptor  33  to secure the biasing element  75  to the adaptor  33 . This can provide even greater stability to the locking system. Other embodiments are also within the scope of the invention. For example, in some embodiments, the locking element  73  and the biasing element  72  could form a one-piece construction. Any of the features that are described herein with respect to a two-piece locking element/biasing element combination could be included in the one-piece locking element. 
     An operator can uncouple the tooth  31  and the adaptor  33  by using, for example, a crowbar or the like. A crowbar can be inserted under a rim  82  of the biasing element  72  to pry the biasing element  72  away from the adaptor  33 . The biasing element  72  is then removed. Any pressure that was previously applied to the locking element  73  is released. The locking element  73  can be disengaged from the interference element  71  by moving it in a rearward direction. Moving the locking element  73  in a rearward direction causes the interference element  71  to move downward. The protrusion  71 ( a ) then disengages from the receiving region  30  of the tooth  31 . The interference element  71  can then be removed and the tooth  31  and the adaptor  33  can be separated from each other. 
     The embodiment shown in FIG. 3 has a number of advantages. First, the wedge-locking system  37  does not need to use a pin to couple the adaptor  33  and the tooth  31  together. Accordingly, hammers need not be used and embodiments of the invention are safer than the conventional pin-based coupling systems. Second, because pins need not be used, the costs associated with damaged pins are eliminated. Third, in embodiments of the invention, the adaptor  33  can be thoroughly cleaned without difficulty. For example, when the tooth  31  and the adaptor  33  are uncoupled from each other, the elements  71 ,  72 ,  73  of the locking system  37  can be removed. The recess  75  that receives and supports the locking element  73  and the biasing element  72  can be easily cleaned. For example, particles such as grit and sand can be removed from the recess  75  by simply brushing the particles in a forward direction so that they pass down the aperture  25  of the adaptor  33  or through the wall-less front region of the recess  75 . Unlike the assembly shown in FIG. 1, the recess  75  does not include a forward wall that obstructs the removal of particles from the recess  75 . Particles that might otherwise abrade the parts of the locking system  37  can be easily removed from the adaptor  33 . Consequently, embodiments of the invention using the locking system  37  mechanism are subject to less wear and a longer working life than assemblies using conventional coupling mechanisms. 
     FIG. 4 shows another embodiment of the invention. In FIG. 4, features that are similar to those shown in FIG. 3 have the same numbering. However, in the embodiment shown in FIG. 4, the two legs  31 ( a ),  31 ( b ) have holes  32 ( a ),  32 ( b ) in them. Each hole  32 ( a ),  32 ( b ) extends to opposite sides of each of the respective legs  31 ( a ),  31 ( b ). The receiving region  30  in the upper leg  31 ( a ) is part of the hole  32 ( a ) in that leg  31 ( a ). If desired, the holes  32 ( a ) can be temporarily plugged or sealed with a suitable material to reduce the amount of debris that might enter the holes  32 ( a ),  32 ( b ). 
     The embodiment shown in FIG. 4 can advantageously be converted to a pin-based coupling system if desired. For instance, the elements  71 ,  73 ,  75  could be removed. A pin could be threaded through the holes  32 ( a ),  32 ( b ) in the tooth  31  and through the aperture  25  in the adaptor  33  to couple the adaptor  33  and the tooth  31  together. Having a convertible assembly is desirable if, for example, the wedge-locking system elements become worn and are not readily available at the operator&#39;s worksite. 
     FIG. 5 shows an interference element according to an embodiment of the invention. In this embodiment, the interference element  100  has a protrusion  100 ( a ), a first portion  100 ( b ) that is generally cylindrical, and a second portion  100 ( c ) that is generally flat. The first portion  100 ( b ) and the second portions  100 ( c ) are at an angle. The protrusion  100 ( a ) has an oblong cross-sectional shape. However, in other embodiments, the protrusion could have a circular cross-sectional shape (e.g., as in a cylinder), a square cross-sectional shape (e.g., as in a block), etc. 
     FIG. 6 shows a perspective view of an adaptor  33  according to an embodiment of the invention. The adaptor  33  includes a recess  81  and an aperture  25 . In this example, the aperture  25  is in the recess  81 . As shown, the recess  81  has a rear abutment wall that slopes downward in a forward direction, and two sidewalls. Each sidewall has a height that gradually decreases from the top of the abutment wall towards the front of the adaptor  33 . The front region of the recess  81  does not include a wall. Advantageously, an operator can readily clean the recess  81  by simply scraping, brushing, or blowing debris (e.g., sand, dirt, and rocks) from the deepest part of the recess  81  near the abutment wall towards the wall-less front region of the recess  81 . The debris can pass down the aperture  25  in the adaptor  33  and off the front of the adaptor  33 . In embodiments of the invention, there are many different paths through which debris can be removed from the recess  81  so that the recess  81  can be thoroughly cleaned. After cleaning, the recess  81  is substantially free of debris (e.g., particles). 
     FIG. 7 shows a perspective view of an interference element  87 , a first portion of which is disposed in the aperture of the adaptor  33 . In this example, the interference element  87  includes a protrusion  87 ( a ) that is round. The second portion  87 ( c ) of the adaptor  33  is substantially flat and has a width that is substantially equal to the width of the recess  81 . 
     In this embodiment, the interference element  87  can also be used as a cleaning tool as well as a part of a locking system. Since the interference element  87  is used to secure the tooth to the adaptor  33 , and is essentially always present near the recess  81  in the adaptor  33 , a cleaning tool is always readily available for the operator to use. An operator can grasp the substantially cylindrical first portion (not shown) of the interference element  87  and can use the second portion  87 ( c ) of the interference element  87  to scrape and remove debris from the recess  81 . For example, the operator can insert the second portion  87 ( c ) of the interference element  87  into the recess  81  near the rear abutment wall. The operator can then move the interference element forward while keeping the second portion  87 ( c ) in contact with the bottom surface of the recess  81 . Debris such as particles pass up the sloping bottom wall, into the aperture in the adaptor  33  or past the wall-less front region of the recess  81 , and off of the adaptor  33 . 
     FIG. 8 shows a top perspective view of a one-piece locking element. As shown, the locking element  91  includes a biasing portion that is proximate the rear of the adaptor  33  and a wedge-shaped front portion  91 ( a ) that is proximate the front of the adaptor  33 . The wedge-shaped front portion  91 ( a ) has cutout area for receiving the substantially cylindrical first portion of the interference element  87 . Generally, the biasing portion is thicker than the wedge-shaped front portion  91 ( a ). 
     As shown in FIG. 9, the locking element  91  can be inserted under the interference element  87  so that the wedge-shaped front portion  91 ( a ) engages both the substantially cylindrical first portion and the substantially flat second portion of the interference element  87 . The cutout area engages the cylindrical first portion of the interference element  87 . The wedge-shaped front portion pushes the interference element  91  up as the locking element  87  is pushed toward the interference element  91 . A rectangular pin  77  that is biased with an internal spring then engages a slot in the adaptor to secure the locking element  91  to the adaptor  33 . 
     The terms and expressions which have been employed herein are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding equivalents of the features shown and described, or portions thereof, it being recognized that various modifications are possible within the scope of the invention claimed. Moreover, any one or more features of any embodiment of the invention may be combined with any one or more other features of any other embodiment of the invention, without departing from the scope of the invention.

Summary:
A locking system for coupling a first member including an aperture, and a second member having a receiving region is disclosed. The locking system comprises: (a) an interference element including (i) a first portion that fits within the aperture when the locking system couples the first member and the second member together, (ii) a second portion, wherein the first portion forms an angle with respect to the second portion, and (iii) a protrusion that extends into the receiving region when the locking system is in use; and (b) a locking element that engages the second portion of the interference element when the locking system is in use.