Abstract:
In accordance with one aspect of the present invention, a latching system is provided for use with machines with front or rear guards assembled to protect certain components, that otherwise may get damaged during machine reversing or turning operations in narrow workplaces, such as a mine site. The locking system comprises a hood assembly, a guard assembly, a motor structured and arranged to move the hood assembly between an open and closed position, a sensor to detect position of guard assembly, and a latch assembly. The latch assembly including a support member enables or disables the guard assembly movement. When the guard assembly is in open position it is restricted and simultaneously the sensor urges to interact with a hood operating system that would allow the hood to operate. Alternatively, when the latching system of the guard assembly is unlocked manually, the sensor disables the hood operating system.

Description:
TECHNICAL FIELD 
       [0001]    The present disclosure relates to a guard assembly for a machine and more specifically to guard assemblies which pivot to allow access for motor driven engine hood assemblies to provide unobstructed engine hood opening. 
       BACKGROUND 
       [0002]    Typically, mining machines used in confined spaces such as in a tunneling environment operate in narrow spaces and often require a machine body protection system to protect the front and rear portions of the machine which include hoods and less robust cosmetic parts such as body panels and light assemblies which are vulnerable to damage during reverse or turning operations. These protecting systems are often structurally integrated with frame of machine, so that should an impact occur it can then be relayed to and absorbed by the frame. As a result, body components such as, bumpers, hoods, lamps, doors, etc., are protected by use of such guards. 
         [0003]    Guard assemblies which protect moveable engine compartment hoods, which may be opened or closed, have to be positioned so that the normal opening of such hood does not create interference with the guard assembly. For example, if the engine compartment hood is motor driven and manually actuatable, an operator opens the hood by activating a switch typically provided in the operator station. In situations where a large machine incorporates a guard assembly, the hood is operated may be opened via a hydraulic press or motor or may be opened using an electric motor with linkage to open the hood in response to the motor being activated. However, it is difficult for an operator to move the guard assembly prior to activating the switch which opens the hood. In fact, if the hood tilts outwardly from the machine when the hood pivots open then the hood may contact the closed guard assembly which is undesirable. Moreover, an operator may not be able to quickly judge whether the guard assembly is open or closed at the time it is desired to open the hood. In this situation, the operator may be required to exit the machine to confirm the position of the guard and subsequently re-board the machine if the guard is not obstructing the hood. This may cause undue fatigue on the operator and lead to inefficient machine operation. Therefore, a guard system which may overcome one or more of these deficiencies would be desirable. 
         [0004]    U.S. Pat. No. 7,992,665B2 discloses a split hood assembly that may be operated in two modes. In the first mode the radiator guard alone may be manually opened and in the second mode, the entire hood assembly may be operated using a powered system. The hood operating or actuating switch is located away from the rear portion of the machine therefore the operator must leave the machine to ensure that the radiator guard is in a closed position prior to activating the hood switch otherwise the hood may contact the radiator guard. As a result the operator must confirm the position of the radiator guard prior to activating the hood assembly which may be time consuming and tedious for the operator. 
       SUMMARY OF THE INVENTION 
       [0005]    In accordance with one aspect of the present invention, a latching system is provided for use with machines with front or rear guards assembled to protect the softer components such as lamps, hood, doors etc., that otherwise may get damaged during machine reversing or turning operations in narrow workplaces, such as a mine site. The locking system comprises a hood assembly, a guard assembly, a motor structured and arranged to move the hood assembly between an open and closed position, a sensor to detect position of guard assembly, and a latch assembly. Further, the latch assembly includes a support member having a first end and a second end, the first end of the support member being pivotably attached to a hood support structure, the second end having a contact portion and the second end being retained by the guard assembly. A locked position of the support member is defined when the motion of guard assembly is being restricted and clear of the hood. An unlocked position is defined when the support member is re-positioned such that the guard assembly is not restricted. When the guard assembly is in the locked position simultaneously a sensor urges to interact with a hood operating system that would allow the hood assembly to open or close. A manual intervention is required to switch the support member in order to change the locked position of the guard assembly to unlocked position. Through the mechanism of providing the latch system, an accidental enablement of the hood operating system by an operator while the guard is in a position that may obstruct the hood operation is eliminated. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a perspective view of an exemplary work machine illustrating a rear guard assembly structured to interact with the tilting engine compartment hood for unobstructed movement of the hood according to the present disclosure; 
           [0007]      FIG. 2  is a perspective view of the rear portion of work machine of  FIG. 1 , illustrating the rear guard assembly and the hood assembly opened for allowing access to the engine and maintenance stations; 
           [0008]      FIG. 3  is a diagrammatical and schematical view of the rear portion of work machine of  FIG. 1 , showing a latch assembly to hold the guard assembly opened and the hood assembly is shown in a closed position and portions of a hood disconnect circuit are illustrated in accordance with the present disclosure; 
           [0009]      FIG. 4  is a partially exploded and enlarged view of the latch assembly illustrated in  FIG. 3 ; 
           [0010]      FIG. 5  is a partial view of the rear guard assembly of  FIG. 3  in two positions, one being the open position (solid) and a interim position (dotted line), with the machine and hood assembly removed to illustrate the slider block of the slider assembly in these positions; and 
           [0011]      FIG. 6  is an enlarged fragmented view of a portion of the rear guard assembly of  FIG. 3 , illustrating two positions of a slider block of the slider assembly, one position (in solid line) immediately prior the door is completely opened and the other position (in dotted line) to illustrate the slider in a dropped and locked position corresponding to the door being completely in the open position. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    Referring to  FIG. 1 , a work machine  100  is shown and includes a frame  101 , a front portion  102 , a rear portion  104 , and a bucket  106  which is located at the front portion  102  of machine  102 . The rear portion  104  of machine  100  includes an engine compartment  108  ( FIG. 2 ), a hood assembly  110 , and a bumper assembly  112 . The hood assembly  110  generally encloses the engine compartment  108  as is customary. The bumper assembly  112  extends across the outermost extents of the rear portion  104  of machine  100  to protect the same from low impact contact with surrounding objects. Work machines  100  which operate in harsh environment conditions may benefit from certain machine guarding equipment to protect certain components which may be affected by impact. In an exemplary embodiment, the work machine  100  may be a wheel loader being operated in a mining site for example, however it is contemplated that the present disclosure may be adapted to other machines in many other work environments. A latching system will be explained hereafter that allows the operation of the hood assembly  110  by integrating the operation of a guard assembly  130  with a latching assembly  146 , based on the position of said guard assembly  130 . 
         [0013]    Referring to  FIG. 2 , the hood assembly  110  includes an engine enclosure  114  and a radiator guard  116 . Specifically, the engine enclosure  114  includes a top panel  118 , a pair of side panels  120 , and an exhaust stack  122  mounted on the top panel  118 . The radiator guard  116  forms a portion of the engine enclosure  114  and includes a top panel  124 , a pair of sidewall panels  126 , and a radiator grill  128  encloses an end of the engine compartment  108  and is connected to the top panel  118  of radiator group  124 . In an exemplary embodiment of the disclosure, the radiator guard  116  may be opened and closed using a gas spring (strut) mechanism, which is known to those with ordinary skill in the art. 
         [0014]    As best seen in  FIG. 3 , the engine enclosure  114  may be hinged (see  FIG. 2 ) and therefore opened and closed using the hood actuation system  129 . The hood actuation system  129  may include at least one actuator or motor  170  which may be an electric motor known to those with ordinary skill or it may be a hydraulically actuator also known to those with ordinary skill, for example. A switch  172  may be provided within the hood actuation system  129  to close or open the circuit, as the case may be, to initiate the opening/closing of the engine enclosure  114 . The switch  172  may be placed at a convenient location, such as inside an operator station (not shown) or on the exterior of operator station near the access door of the work machine  100 . 
         [0015]    The guard assembly  130  of the present disclosure will now be described. Guard assembly  130  is located at the rear portion  104  of the machine  100  and is positioned to generally protect the engine enclosure  114 , radiator guard  116 , lamps (not shown) and other portions of machine  100  which may be subject to impact and possible damage if an impact event occurred. Such risk of impact may occur, for example, if multiple machines are operated in a small area or during turning and reverse operations of the work machine  100  such as in narrow work sites (i.e., tunnels, mine shafts, etc). In an exemplary embodiment of the present disclosure, guard assembly  130  may be a single piece guard which is adapted to pivot open/closed via two vertically arranged hinges  136 . The guard assembly  130  connects to the frame  101  of the machine  102  via an elongated plate-shaped mounting portion  138  of the guard assembly  130 . 
         [0016]    The guard assembly  130  includes a guard panel or door  132 , a lock  134 , and the pair of hinges  136  and the mounting portion  138 . As best shown in  FIGS. 3 and 4 , the guard assembly  130  further includes a latch support plate  140  attached to the bottom  131  of the door  132 . The latch support plate  140  is provided with a grooved portion or slot  141 , extending along the width of the door  132 . The slot  141  of the latch support plate  140  includes a narrow cut portion or channel  142  which extends along the latch support plate  140  with a circular aperture  144  at the end of the slot  141 . The location of aperture  144  coincides with receiving a hat-shaped slider member  156  of a latch assembly  146  when the door is in a fully opened position as will be hereinafter described. The guard assembly  130  also includes latch assembly  146 . Latch assembly  146  includes a u-shaped support member  150 . Support member  150  includes a hinge end  152  and a locking end  154 . Locking end  154  of support member  150  receives the slider member  156  and an outer perimeter portion  157  of the slider member  156  is sized to fit and interlock within the aperture  144  coinciding with the door being fully opened ( FIG. 6 ). In contrast, the hinge portion  152  of the support member  150  is captured (i.e., allowed to rotate and move up and down) by hinge strap  148 , and in turn, hinge strap  148  is mounted to the frame  101  of machine  100 . Therefore, the hinge portion  152  of support member  150  co-acts with the hinge strap  148  by translating within the hinge strap  148  when the support member  150  is moved upward by an operator and thereafter as the door  132  swings open/closed the hinge portion  152  of support member  150  rotates within hinge strap  148 . 
         [0017]    Therefore, the support member  150  can freely rotate about the hinge portion  152  and at the same time the slider member  156  can slide within the slot  141  of the latch support plate  140 . The slider block  156  includes a head portion  158  and a body portion  160 . The size of the head portion  158  is less than the size of the aperture  144 . In  FIG. 5 , the location of slider block  156  is exaggerated and shown well above the latch support plate  140 , for the purpose of explanation. In the exemplary embodiment of the invention, the slider block  156  rests on top of the latch support plate  140 . 
         [0018]    In an exemplary embodiment of the disclosure, a sensor  162  such as a proximity sensor is placed underneath the aperture  144  of the latch support plate. The sensor  162  is therefore positioned to co-acts with a probe portion  160  of slider member  156 , such that as the probe portion  160  drops down into a position when the door  132  is fully opened, and then the probe portion  160  will approach the sensor  162  contemporaneously as the slider member  156  moves through the aperture  144  in the latch support plate  140  to activate the sensor coinciding with the door  132  being fully open (i.e., a locked event). The sensor  162  is electrically connected to an electrical motor  170  with a relay switch  166  therebetween. The electrical motor may be coupled to a hydraulic pump  164  or the electric motor may have a screw driven drive shaft in direct contact with the engine enclosure  114 . In an exemplary embodiment, the hydraulic pump  164  may be fitted with hydraulic hoses  174 ,  176  which are in fluid communication with a hydraulic actuator (not shown) to open/close the engine enclosure  114 . It will be understood that the motor  170  may be any other alternative driver to open/close enclosure  114  known to those having ordinary skill in the art. 
         [0019]    Referring to  FIG. 3 , the hood actuation system will now be described. In an exemplary embodiment, the hydraulic pump  164  is coupled to the electrical motor  170 . The electrical motor  170  is electrically connected to an electrical switch  172 , such as, for example a known on-off toggle type switch. The location of switch  172  may be placed at any convenient location such as within the cab or outside the cab near the cab entry region. The switch  172  may be placed on the platform  163  ( FIG. 1 ) of the machine  100  so that the operator can reach the switch while standing on the ground. 
         [0020]    It is to be understood that individual features shown or described for one embodiment may be combined with individual features shown or described for another embodiment. The above described implementation does not in any way limit the scope of the present disclosure. Therefore, it is to be understood although some features are shown or described to illustrate the use of the present disclosure in the context of functional segments, such features may be omitted from the scope of the present disclosure without departing from the spirit of the present disclosure as defined in the appended claims. 
       INDUSTRIAL APPLICABILITY 
       [0021]    The guard assembly  130  of the present disclosure has the functionality of protecting certain components such as, lamps, bumper, radiator grill, radiator, the engine enclosure, and other non-structural panels, etc., which are externally positioned on the machine  100  and subject to contact. The hood assembly  110  may be operated to open or close by an operator however the swinging guard assembly  130  must first be open and clear of the hood assembly  110 . The hood opening mechanism initiates activation of the hydraulic actuator (not shown) to open or close the engine enclosure  114  with suitable force only if the hood activation system is activated coinciding with the door being in the fully open position. If the guard assembly  130  is not fully opened and thus activation of the sensor  162  has not occurred then the motor  170  to open/close the hood assembly  110  will not be activatable. 
         [0022]    Referring to  FIG. 5 , the locking mechanism for the door  132  of the guard assembly  130  includes the support member  150  which allows the door to be opened until it has reached a fully open position then the support member  150  drops and the slider member  156  locks into the aperture  144  of the latch support plate  140 , the latch support plate being bolted to the door  132 . Further, a sensor  162  co-acts with the slider member  156  by simultaneously activating the hood operating system corresponding with the rod falling into position to activate the proximity sensor. In this manner, the door of the guard assembly must be open and completely out of the way to activate the proximity switch which assures that the door will be open and not obstructing the hood assembly as the hood is opened. 
         [0023]    More particularly, as the door  132  of the guard assembly  130  is being rotated from a closed position of the door  132  to a fully open position of the door  132 , the head portion  158  of slider block  156  slides over the latch support plate  140 , and the body portion  160  of the slider block  156  slides within the narrow cut portion  142 . In  FIG. 5 , the location of slider block  156  is exaggerated and shown well above the latch support plate  140  to illustrate that the probe portion of the slider block is not in proximity with the sensor and should therefore not be activated. The slider block  156  rests on top of the latch support plate  140 . This sliding motion of the body portion  160  of slider block  156  within the slot  141  of the latch support plate  140  is defined as ‘swing event’. During the swing event, the motion of slider block  156  of slider assembly  150  is in a horizontal plane. 
         [0024]    When the door  132  reaches a fully open position, the head portion  158  of the slider block slips into the large aperture  144 , due to gravity. This action of slider assembly falling by weight is defined as the ‘locking event’. After the locking event, the movement of the door  132  is completely restricted. Simultaneously the proximity sensor  162  urges the electrical connection between the switch  172  and the electric motor  170  to a closed circuit. After this circuit between switch  172  and electrical motor  170  is closed, an operator may operate the hood assembly  110  using the toggle switch  172 . 
         [0025]    Once the hood assembly  110  is closed again using the switch  172 , to unlock the door  132 , the slider assembly  150  would be manually lifted up such that the bottom face of slider block  156  is above the upper face of latch support plate  140 , and guide the body portion  160  of slider block  156  within the narrow cut portion  142  of the latch support plate  140 . The lifting of slider assembly  150  would urge the sensor to disconnect the power to the hood operating circuit. Therefore, any further accidental operation of switch  172  by the operator will not cause hood operation. 
         [0026]    While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.