Patent Publication Number: US-2016222634-A1

Title: Device for securing teeth to tooth adapters of an earth-moving machine through pins

Description:
TECHNICAL FIELD 
     The present invention relates to a device for securing implements to heavy machines by means of pins; in particular, said implements may be teeth for earth-moving machines. 
     BACKGROUND ART 
     In the field of heavy machines, devices are known which are used for securing implements to such machines by means of pins. Such devices can be used in combination with different type of machines, including earth-moving machines. 
     With particular reference to the field of earth-moving machines, excavators, for example, are equipped with a bucket or a blade connected to the end of a movable arm for breaking up and moving earth, the characteristics of which may vary extensively. 
     The bucket of such machines is generally fitted with one or more teeth, or tips, which can be connected thereto in a removable manner, so that such teeth can be replaced when worn or should they break during use, without requiring the replacement of the whole bucket, which would be a very expensive and difficult task. 
     In particular, the teeth are secured in different ways to protuberances, also known as tooth adapters, arranged along the lower edge of the bucket. An old fastening method requires the use of a pin or key to be forcedly driven with a hammer into a series of holes between the tooth adapter of the bucket and the tooth; once inserted, the pin is received into a deformable element, e.g. a rubber element or ring, which can generate friction that holds the various pieces in position while using the machine. 
     This method is, of course, not very safe and practical, in particular when small excavators must be used and the room between the tooth adapters of the bucket is not enough to allow the use of a hammer. In addition, when big pins are used much force needs to be exerted with the hammer in order to insert the pin and create the required friction with the ring. 
     Another problem is the low level of safety for operators using hammers or clubs for inserting the pin. 
     A further drawback is that such devices work mainly by friction, and the pin has much clearance within the spaces in which it is inserted; therefore, there is more likelihood that the pin might come off, particularly when the bucket is working into hard ground or in the presence of water: in such cases, vibrations and water will remove the thin layer of earth deposited in the interstices between the tooth, the bucket and the fastening device, which is useful for increasing friction and holding the pieces in mutual contact. 
     When the machine is in use, one or more pins coming off will cause a number of problems, including: higher costs; danger due to fall of tips from the bucket raised above ground; wear of the “uncovered” tooth adapter, and hence of the bucket itself. 
     For these reasons, in recent years less “invasive” fastening techniques have been developed, which are however not very practical, especially because they are prevalently intended for use in building yard environments, where water and debris are often present. 
     For example, document ES1068766U illustrates a device comprising a partially threaded through pin, intended for cooperating with a threaded washer having a locking means, e.g. a groove, into which an operator inserts a screw or pin for holding it in position, thereby preventing the parts from coming out of their seat. 
     An additional drawback is that the (big) through pin and the (small) locking screw must presumably be screwed by using two different wrenches, resulting in a more complex replacement operation. Moreover, when working in an outdoor environment some of these parts may easily get lost, in particular the locking screw. 
     SUMMARY OF THE INVENTION 
     It is one object of the present invention to provide a device for securing teeth to a tooth adapted of an earth-moving machine by means of pins, which can be produced in a simple and economical manner. 
     It is a further object of the present invention to provide a device having a number of functional features, including ease of installation and removal, operator safety, and reliability, mainly due to a reduced risk of losing teeth from the tooth adapters. 
     In particular, according to one or more embodiments of the present invention, a pin is used which can be manually inserted into and extracted from suitable holes without requiring the use of hammers, clubs or the like; this technology is also referred to as “hammerless”. 
     According to the present invention, this and other objects are achieved through a device made in accordance with the appended claim  1 . 
     It is to be understood that the appended claims are an integral part of the technical teachings provided in the following detailed description of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further features and advantages of the present invention will become apparent from the following detailed description, which is supplied by way of non-limiting example with reference to the annexed drawings, wherein: 
         FIG. 1  is a view of an implement connected to a machine by means of the present invention; 
         FIG. 2  is an exploded view of one example of a device in accordance with the present invention; 
         FIG. 3  is a sectional view of the device shown in  FIG. 2 , in a retracted condition; 
         FIG. 4  is a sectional view of the device shown in  FIG. 2 , in an extracted condition; 
         FIG. 5  is a sectional view along line V-V of the device shown in  FIG. 4 ; 
         FIG. 6  is a sectional view of a second embodiment of the device; 
         FIG. 7  is a sectional view along line VII-VII of the device shown in  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to the above-listed drawings, a device connects an implement  3  to an implement carrier  4 . In particular, implement  3  is a tooth  3 , and implement carrier  4  is a tooth adapter  4  of a bucket  5  belonging to an earth-moving machine, e.g. an excavator useful for excavating/moving earth. 
     As will be apparent to a man skilled in the art, implement carriers  4 , in this case tooth adapters  4  of bucket  5 , are shaped in such a way as to at least partially enter a cavity formed in implements  3 , which are intended for being mounted on the machine and replaced as necessary. It is therefore necessary to use a device capable of firmly keeping implement  3  in contact with implement carrier  4  while the machine is in use. 
     “Hammerless” device  1  comprises a pin  10  to be removably inserted through at least one first aperture  12  on an implement  3  and one second aperture  14  on an implement carrier  4  of a machine. 
     Device  1  comprises at least one expanding element  20  adapted to reversibly switch between a retracted position, in which said expanding element  20  is at a minimum distance from the longitudinal axis x-x of said pin  10 , to an extracted position, in which said expanding element  20  is at a maximum distance from the longitudinal axis x-x of said pin  10 . 
     In accordance with an advantageous embodiment illustrated in  FIGS. 1 to 5 , expanding element  20  is adapted to reversibly switch from said retracted position to said extracted position by moving in a plane substantially perpendicular to the longitudinal axis x-x of said pin  10 . In other words, expanding element  20  is adapted to reversibly switch from the retracted position to the extracted position by moving transversally relative to the longitudinal axis x-x of pin  10 . 
     Device  1  further comprises at least one retaining element  22  associated with at least one of said first and second apertures  12 ,  14 , and provided with at least one seat  24  for at least partially receiving said at least one expanding element  20  when said at least one expanding element  20  is in said extracted position. 
     Retaining element  22  is associated with at least one of the first and second apertures  12 ,  14  through methods which are per se known; for example, it is possible that a cavity, also known as “counterbore”, is formed on at least one of said first and second apertures  12 ,  14 , into which retaining element  22  can be at least partially inserted. 
       FIG. 1  shows one advantageous embodiment of the present invention, wherein tooth  3  has a cavity into which tooth adapter  4  is inserted, and two first apertures  12  are present on the faces that delimit the cavity; pin  10  is then inserted through the first apertures  12  on tooth  3  and through the second aperture  14  on tooth adapter  4  of bucket  5 . 
     That part of tooth adapter  4  which must be inserted into the cavity of tooth  3  is also known as “catch”; however, reference will only be made below to tooth adapter without departing from the protection scope of the present invention. 
       FIG. 2  shows one advantageous embodiment of the present invention, wherein pin  10  has a substantially cylindrical outer surface; other shapes are however also conceivable, e.g. prismatic with a square, rectangular, triangular, polygonal, etc. cross-section. 
     Expanding element  20  comprises a pair of balls on diametrically opposed sides relative to axis x-x of pin  10 , which are adapted to move along a radial path while reversibly switching between the extracted and retracted positions. 
     Further variants are also conceivable, wherein the pin contains a different number of expanding elements  20  (or even just one). 
     In addition, expanding element  20  may, still in accordance with the present invention, have other non-limiting shapes, including: bar, parallelepiped, cylinder, ellipse, etc. 
     In other words, expanding element  20  (which in the case illustrated herein is spherical in shape) is a movable element, preferably a sliding element, susceptible of moving between the extracted condition and the retracted condition. 
     Retaining element  22  shown herein has a substantially annular shape, and includes a seat  24  formed on the face of retaining element  22  which is closer to pin  10 . Said seat is a recess so shaped as to easily receive expanding element  20 , which in this case consists of a pair of balls. 
     In the illustrated example, seat  24  advantageously has a continuous annular development along the entire retaining element  22 , so as to be able to receive expanding element  20  irrespective of the angle between pin  10  and retaining element  22 . 
     In accordance with further variant embodiments (not shown), device  1  comprises multiple seats  24  arranged on retaining element  22 , each one intended for receiving one or more expanding elements  20 . 
     Retaining element  22  may have different shapes, preferably compliant with the shape of the cross-section of pin  10 , such as: square, rectangular, triangular, polygonal, open section, “C” section, etc. 
     With reference to  FIG. 3 , device  1  is in the retracted position, in which expanding elements  20  (in this case, balls) are close to axis x-x and do not protrude past the outer surface of pin  10 . Balls  20  are not in contact with retaining element  22 , and therefore a relative movement (along the axis x-x) is possible between pin  10  and retaining element  22 , which allows pin  10  to be extracted from apertures  12 ,  14  and tooth  3  to be disengaged from tooth adapter  4  of bucket  5 . 
     In the illustrated embodiment, device  1  comprises at least one duct  26 , formed in pin  10  and allowing the reversible movement of the at least one expanding element between the extracted condition and the retracted condition. 
       FIG. 4  shows device  1  in the extracted position, in which balls  20  protrude at least partially past the outer surface of pin  10  for mechanically cooperating with retaining element  22  to prevent any relative movement between pin  10  and retaining element  22 , so as to firmly engage tooth  3  with tooth adapter  4  of bucket  5 . 
     Device  1  further comprises an actuator  30  adapted to allow said at least one expanding element  20  to reversibly switch from the retracted position to the extracted position. 
     In particular, as shown in  FIGS. 3 and 4 , actuator  30  is a threaded screw to be at least partially inserted into a hole  32  provided on the pin. A user will act upon screw  30 , typically by means of a wrench, in order to bring said screw  30  closer to the at least one expanding element until they come in contact with each other; at this point, the tip of screw  30  will push, as it goes forwards, expanding element  20  towards a position farther away from axis x-x, i.e. towards the extracted position, thus securing tooth  3  to bucket  5  and allowing the excavating machine to be normally used. Likewise, when tooth  3  needs to be replaced, the user will undo screw  30  to move the at least one expanding element  20  into the retracted condition, thus allowing removal of pin  10 . 
     In  FIG. 5  two ducts  26  are visible, through which the two balls  20  slide in order to switch from the retracted position to the extracted position, and vice versa, under the action of actuator  30 . Ducts  26  are arranged radially relative to the axis x-x of pin  10 , and are substantially straight. 
     In this variant, screw  30  is coaxial to pin  10 . 
     However, actuator  30  may also move along an axis that does not coincide with axis x-x. 
     If actuator  30  is a threaded screw, it is also conceivable to use a self-locking element, or self-locking material, suitable for preventing the screw from loosing accidentally and causing expanding element  20  to move from the extracted position to the retracted position. 
     According to a further embodiment (not shown), actuator  30  can move said at least one expanding element  20  by means of a gear or a gear system. 
     According to yet another embodiment, actuator  30  can move said at least one expanding element  20  by means of a lever or a lever system. 
     For simplicity, retaining element  22  will be referred to below as a “ring”, without however limiting the scope of the invention. 
       FIGS. 6 and 7  illustrate a second embodiment of the present invention, which comprises an elastic means  34  capable for bringing said at least one expanding element  20  towards one of the extracted position and the retracted position. Advantageously, elastic means  34  is a spring, such as a coil spring. Other per se known elastic means  34  may alternatively be used, such as, for example, a disk spring, or an elastically deformable element, such as a reed or a small bar, a rubber element, or chemical materials having an elastic behaviour. 
     Preferably, elastic means  34  is adapted to bring expanding element  20  towards the extracted position. 
     After having inserted pin  10  through holes  12 ,  14  of tooth  3  and of tooth adapter  4 , the user will associate the ring with pin  10 ; then, by operating actuator  30 , the user will bring the expanding element into the extracted condition in order to mechanically secure the ring to pin  10 , thereby preventing them from mutually sliding along axis x-x, hence securing tooth  3  to tooth adapter  4 . Thanks to the presence of elastic means  34 , which will tend to hold expanding elements  20  in the extracted position, in order to place the ring into the correct position along axis x-x of pin  10  the user will have to slide the ring along pin  10  against the resistance opposed by elastic means  34 , which will tend to hold expanding elements  20  in the extracted condition. In fact, when pin  10  is not associated with the ring, expanding elements  20  protrude at least partially from the external side surface of pin  10 , and therefore the ring will encounter an obstacle while sliding along pin  10 . 
     In the absence of elastic means  34 , there is a risk that the ring might be incorrectly secured to pin  10 . In fact, in difficult working conditions the user might bring expanding element  20  into the extracted condition without however positioning the ring to correctly receive expanding element  20  (i.e. without the ring and pin  10  being properly aligned along axis x-x). In such a situation, pin  10  might slide off the ring, resulting in the risk that pin  10  might come out of the holes of tooth  3  and of tooth adapter  4 , thus causing the tooth to be detached from the tooth adapter. 
     Therefore, the presence of elastic means  34  prevents the risk that the ring might be incorrectly secured to pin  10 , because it will be easy for the user to understand when pin  10  and the ring are in the proper mutual position, and then to operate actuator  30  in order to lock expanding elements  20  in the extracted condition, thus securing tooth to tooth adapter  4 . After the ring has been properly positioned on pin  10 , expanding elements  20  will, through the effect of elastic means  34 , move away from axis x-x of pin  10 , arranging themselves in the extracted condition in abutment with seat  24  of the ring; at this stage, a short vibration and a “clack” noise may be generated because of the sudden movement of expanding elements  20 . The user can thus easily perceive that pin  10  and the ring have been properly engaged. 
     In the illustrated example, elastic means  34  is positioned between two expanding elements  20 , and exerts a repulsion force on such expanding elements  20  that tends to move them away from axis x-x into the extracted position. A first end (on the right in the drawing) of elastic means  34  is in contact with one expanding element  20 , while a second end (on the left) of elastic means  34  is in contact with the other expanding element  20 . Elastic means  34  is arranged in ducts  26 . 
     According to another variant (not shown), pin  10  may be equipped with one elastic means  34  for each expanding element  20 . Elastic means  34  may be associated with an abutment portion of pin  10 ; thus, a first end of elastic means  34  is in contact with one expanding element  20 , and a second end of elastic means  34  is associated with the abutment portion. 
     With particular reference to the illustrated embodiment comprehensive of elastic means  34 , in the absence of actuator  30  one can engage/disengage pin  10  and the ring by applying a force overcoming the force exerted by elastic means  34  to hold the expanding elements  20  in the extracted condition, thus allowing mutual sliding between pin  10  and the ring. In this case, actuator  30  will contribute to hold expanding means  20  more firmly in said extracted condition in contact with the ring, thus minimizing the risk that pin  10  and ring might accidentally come off. 
     In the particular variant embodiment shown in Figures and  7 , the outer surface of pin  10  has a shape that limits the sliding of the ring along axis x-x of the same pin  10 . 
     Advantageously, the outer surface of pin  10  has two different cross-sections along its axis x-x (the cross-sections are perpendicular to the axis x-x). In particular, pin  10  includes a first portion  10   a  with a smaller cross-section and a second portion  10   b  with a larger cross-section. In the variant that uses a substantially cylindrical pin  10 , the two cross-sections are two circumferences having different diameters. 
     Portion  10   a  of pin  10  that extends from a first end of the latter (the upper end in  FIG. 6 ) to expanding elements  20  has a smaller cross-section; the remaining portion  10   b  of pin  10  has a larger cross-section. Thus, the outer surface of pin  10  has a configuration that resembles two superimposed coaxial cylinders. 
     The difference between the cross-sections of the two portions  10   a ,  10   b  of the outer surface of pin  10  creates a projection (i.e. an abutment, a stop portion or the like) which is useful for limiting the sliding movement of the ring along pin  10 , so that the ring can be correctly positioned on pin  10  during the insertion step. Therefore, after having inserted pin  10  through tooth  3  and tooth adapter  4 , the user will push the ring towards pin  10 ; the ring will slide over pin  10  until it meets the projection, where it will stop. At this point, pin  10  and the ring will be in the correct mutual position that will allow expanding elements  20  to move into the extracted condition within seat  24  of the ring, thereby securing the assembly. 
     The presence of elastic means  34  and of the projection on the outer surface of pin  10  allows the operator to associate together pin  10  and the ring in a faster, easier and more reliable manner, thereby minimizing the risk of incorrect assembly and obtaining a confirmation that the parts have been assembled correctly. 
     It must be pointed out that the features of elastic means  34  and of the projection may be individually present in device  1  of the invention, and that they may be combined with any other features of the present invention, unless they are technically incompatible. 
     As can be seen in some of the drawings, device  1  may be so shaped as to be able to receive a tool or wrench, so that said device  1  can be held while an operator is acting upon actuator  30 . For example, if actuator  30  is a screw, on the side opposite to said screw there may be a housing adapted to receive a second tool (e.g. an Allen wrench), so that the necessary torque can be applied without device  1  turning within apertures  12 ,  14 . 
     Optionally, device  1  comprises a housing formed on pin  10  and shaped for receiving a tool or wrench. Housings are generally formed at the ends of pin  10 , along the longitudinal axis x-x thereof. Device  1  illustrated in  FIG. 6  comprises a pair of housings: the first housing  40  is located at hole  32  that accommodates actuator  30  (upper part of the drawing), and the second housing  42  is formed at the end of portion  10   b  of the pin (lower part of the drawing). 
     Advantageously, device  1  comprises a closing element  50 ,  52 , e.g. a plug or the like, for closing the respective housing. This will avoid undesired entry of debris and dirt, ensuring better efficiency and a longer life of device  1 . 
     Closing element  50 ,  52  is removable, thus allowing the tools to be inserted into respective housing  40 ,  42 . Closing element  50 ,  52  may be made of any material; preferably it is made of rubber or plastic. Closing element  50 ,  52  may have many different shapes, e.g. cylindrical, truncated cone, parallelepiped, etc. 
     Of course, without prejudice to the principle of the invention, the forms of embodiment and the implementation details may be extensively varied from those described and illustrated herein by way of non-limiting example, without however departing from the scope of the invention as set out in the appended claims.