Patent Publication Number: US-8528681-B2

Title: Bonnet sealing structure for work machine

Description:
BACKGROUND 
     The present invention relates to a bonnet sealing structure of a swiveling work machine, such as backhoe. 
     In a conventional swiveling work machine, such as backhoe, on a rear portion of a swivel stage is mounted an engine, which is covered with a bonnet. The bonnet is formed of front, left and rear covers for covering front, left and rear sides of the engine, respectively, and the like. The front cover and the left cover are fixed to a support frame or the like straddling the engine. The rear cover is made openable and closable relative to the front cover; the rear cover is supported by the support frame or the like openably and closably about a vertical shaft as a fulcrum shaft on one end in a transversal direction of the rear cover (for example, see Japanese patent application JP2005-280485A). 
     With respect to this type of conventional bonnet structure for swiveling operation, a sealing structure disclosed in, for example, Japanese patent application JP2004-150029A is applied thereto as-is, and generally, an upper end portion of the rear cover (open-close cover) is brought into contact with an upper end portion of a fixed cover through a sealing member, when the rear cover is closed. 
     Therefore, in the conventional structure, snow or soil may be accumulated on the sealing member between the upper end portion of the fixed cover and the upper end portion of the open-close cover, and if snow or soil becomes frozen, the sealing member and the portions of the cover in the vicinity thereof may become fixed in an attached state. 
     Therefore, it would be desirable to provide a structure in which snow or soil is prevented from being accumulated on a sealing member between the upper end portion of the fixed cover and the upper end portion of the open-close cover. 
     SUMMARY OF THE INVENTION 
     In one aspect of the present invention, there is provided a bonnet sealing structure for a swiveling work machine including: a bonnet configured to cover an engine provided on a swivel stage including: a fixed cover, and an open-close cover which is swingably supported about a vertical shaft and is openable and closable relative to the fixed cover; a sealing member through which an upper end portion of the open-close cover is brought into contact with an upper end portion of the fixed cover when the open-close cover is closed; and a cover piece protruding from one of an upper wall of the open-close cover and an upper wall of the fixed cover, wherein when the open-close cover is closed, the cover piece is located above the sealing member and reaches a point above the other of the upper wall of the fixed cover and the upper wall of the open-close cover. 
     In the bonnet sealing structure, it would be preferable that the cover piece is provided on the upper wall of the open-close cover, and is provided with a suspended piece protruding downward from a base portion of the cover piece, a standing piece is provided on an end portion of the upper wall of the fixed cover, that stands opposite to the suspended piece and is positioned below the cover piece when the open-close cover is closed, and the sealing member is provided on one of the suspended piece and the standing piece, and is brought into contact with the other of the suspended piece and the standing piece when the open-close cover is closed. 
     It would be also preferable that the engine and a radiator are mounted on a rear portion of the swivel stage, a support frame straddles the engine, the fixed cover configured to cover upper and front sides of the engine is fixed to the support frame, the open-close cover configured to cover a rear side of the engine is supported by the support frame in such a manner that the open-close cover is freely opened and closed about the vertical shaft as a fulcrum shaft on one end in a transversal direction of the open-close cover, the open-close cover includes a cover main body; and an upper cover body which is fixed to an upper end portion of the cover main body and protrudes frontward, and the upper cover body includes the upper wall on which the cover piece and the suspended piece are provided. 
     It would be still preferable that a partition cover configured to separate a space around the radiator into an upstream-side space and a downstream-side space in terms of an air flow direction is fixed to the support frame so as to extend along a free end portion in the transversal direction of the open-close cover, the partition cover includes: a top wall; and a rear wall protruding downward from a rear end of the top wall, on a free end portion of the upper cover body, an upper sealing member is provided which is brought into contact with the top wall of the partition cover when the open-close cover is closed, and on a free end portion of the cover main body, a rear sealing member is provided which is brought into contact with the rear wall of the partition cover when the open-close cover is closed. 
     It would be still preferable that a downward protrusion protrudes downward from a protruding end portion of the cover piece, and the standing piece is positioned below the cover piece and on a suspended piece side relative to the downward protrusion, when the open-close cover is closed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The various aspects, other advantages and further features of the present invention will become more apparent by describing in detail illustrative, non-limiting embodiments thereof with reference to the accompanying drawings. 
         FIG. 1  is a perspective view of an upper portion of a backhoe according to one embodiment of the present invention. 
         FIG. 2  is a plan view of a swivel stage. 
         FIG. 3  is a left side view of a portion of a rear bonnet of the swivel stage. 
         FIG. 4  is a rear view of a portion of the rear bonnet of the swivel stage. 
         FIG. 5  is a plan view of an upper portion of the swivel stage. 
         FIG. 6  is a plan view of a portion of the rear bonnet of the swivel stage. 
         FIG. 7  is a plan view of a portion of a rear cover of the swivel stage. 
         FIG. 8  is a rear view of a portion of the rear cover of the swivel stage. 
         FIG. 9  is a rear view of a left end portion of the rear cover of the swivel stage. 
         FIG. 10  is a plan view of the left end portion of the rear cover of the swivel stage. 
         FIG. 11  is a longitudinal cross section of a portion of the rear cover of the swivel stage. 
         FIG. 12  is a perspective view of the rear cover. 
         FIG. 13  is a perspective view of a portion of a partition cover of the swivel stage. 
         FIG. 14  is a perspective view of a left portion of a counter weight. 
         FIG. 15  is a perspective view of the left portion of the counter weight with a cover member removed. 
         FIG. 16  is a longitudinal cross section of a portion of a rear cover of a swivel stage according to another embodiment. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Hereinbelow, embodiments of the present invention will be described with reference to the accompanying drawings. 
     As shown in  FIGS. 1 to 4 , a backhoe  1  as one example of a swiveling work machine includes a traveling device with a pair of right and left crawler track traveling bodies (not shown), and a swivel stage  2 . The swivel stage  2  is mounted above the traveling device through a swivel bearing, rotatably about a swivel shaft center extending in a vertical direction. 
     The swivel stage  2  includes a swivel base  3  in a shape of a plate and a vertical wall  5  partitioning a space above the swivel base  3  into front and rear spaces. The vertical wall  5  stands on the swivel base  3  in an intermediate portion thereof in a longitudinal direction. The swivel base  3  is provided with a pair of right and left longitudinal ribs  6 , 7  which are away from each other from a front side to a rear side of the swivel base  3 . On a front side of a pair of the right and left longitudinal ribs  6 , 7 , a bracket  9  is provided so as to protrude frontward from the swivel base  3 . Through the bracket  9 , a working device for excavation is installed on a front end portion of the swivel stage  2 . 
     A rear end portion of the swivel base  3  is provided with a counter weight  11 . Frontward of the counter weight  11  in the rear end portion of the swivel base  3 , a mounting wall  12  in a shape of an arc protrudes upward. Frontward of the mounting wall  12  in the rear end portion of the swivel base  3 , an engine  14  is disposed. On a left portion of the swivel base  3 , a fuel tank is disposed, and on a right portion of the swivel base  3 , a battery and an oil tank are disposed. The fuel tank is arranged frontward of the vertical wall  5  and on an immediate left side of the left longitudinal rib  6 . The battery and oil tank are arranged frontward of the vertical wall  5  and on a right side of the right longitudinal rib  7 . 
     In this manner, on a rear side of the vertical wall  5  of the swivel stage  2  is formed an engine room  20 . The engine  14 , a radiator  15  and the like are mounted on a rear portion of the swivel stage  2 , and a hydraulic pump  16  is disposed on a left side of the engine  14 . 
     As shown in  FIG. 5 , frontward of the engine  14  on the swivel stage  2 , a front cover  22  is provided which is configured to serve as a partition on a front side of the engine room  20 . A lower end portion of the front cover  22  is fixed to the vertical wall  5  with fixtures, such as bolt. A rear cover  24  is provided on a rear end portion of the swivel stage  2 , a left cover  25  is provided on a left side of the rear cover  24  on the swivel stage  2 , a right inner wall cover  26  is provided on a right side of the front cover  22  on the swivel stage  2 , and a right cover  28  is provided on a right side of the right inner wall cover  26  on the swivel stage  2 . 
     The front cover  22  includes: a standing wall  31  as a lower front end portion of the front cover  22 ; an inclined wall  32  extending rearward and upward from an upper end of the standing wall  31 ; and an upper wall  33  extending rearward from an upper end of the inclined wall  32 . A lower portion of the standing wall  31  overlaps an upper end portion of the vertical wall  5 , and fixed to the vertical wall  5  with fixtures, such as bolt and nut. On the inclined wall  32  of the front cover  22 , an opening window  35  for inspection purpose is provided, which is closed with a detachable lid member (not shown). 
     The rear cover  24  is disposed above the counter weight  11 . The counter weight  11  and the rear cover  24  together cover a rear side of the engine room  20 . The left cover  25  covers a left side of the engine room  20 . The vertical wall  5  and the front cover  22  together cover the front side and an upper side of the engine room  20 . A rear portion of the right cover  28  covers a right side of the engine room  20 . In this manner, the vertical wall  5 , the front cover  22 , the left cover  25 , a rear portion of the right cover  28 , the counter weight  11  and the rear cover  24  together surround the engine  14  (the engine room  20 ). The right cover  28  covers a right side of the devices on the swivel stage  2 , such as battery and oil tank, and the right side of the engine room  20 . The right cover  28  also covers front, upper and outer side portions of a right front area of the swivel base  3  where the devices, such as battery and oil tank, are mounted. The right inner wall cover  26  covers an inner side portion of the right front area of the swivel base  3  where the devices, such as battery and oil tank, are mounted. 
     A rear bonnet  36  is formed of the front cover  22 , the left cover  25 , the rear portion of the right cover  28  and the rear cover  24 , and a side bonnet  37  is formed of the right cover  28  and the right inner wall cover  26 . 
     As shown in  FIGS. 1 and 2 , on a front side of the vertical wall  5  of the swivel stage  2  and the front cover  22 , an operation part is provided that has a driver&#39;s seat  38  and steering levers. On the front cover  22 , a canopy  39  for protecting the driver&#39;s seat  38  (operation part) stands. 
     As shown in  FIGS. 2 to 8 , a support frame  43  is provided on the rear portion of the swivel stage  2 . The support frame  43  straddles the engine  14  thereabove. The support frame  43  is formed mainly of a left-front leg  45 , a left-rear leg  46 , a right-rear leg  47 , a right-front leg  48  (not shown), a lateral support plate  49  and a longitudinal support plate  50 . The lateral support plate  49  is connected to upper end portions of the legs  45 , 46 , 47 , and the longitudinal support plate  50  protrudes frontward from a right end portion of the lateral support plate  49 , and the right-front leg  48  supports a front portion of the longitudinal support plate  50 . 
     Lower ends of the left-front leg  45  and the right-front leg  48  are fixed to the swivel base  3  through the vertical wall  5  and the like. Lower ends of the left-rear leg  46  and the right-rear leg  47  are fixed to the swivel base  3  through mounting stages  55 , 56  and the like. The lateral support plate  49  is in a shape of a band extending in a transversal direction. A left end portion of the lateral support plate  49  and the upper end portion of the left-front leg  45  are connected and fixed to each other by welding or the like. An intermediate portion of the lateral support plate  49  in the transversal direction is connected and fixed to the upper end portion of the left-rear leg  46  by welding or the like. The right end portion of the lateral support plate  49  is connected and fixed to the upper end portion of the right-rear leg  47  by welding or the like. A rear end portion of the longitudinal support plate  50  is connected and fixed to the right end portion of the lateral support plate  49  and also to the upper end portion of the right-rear leg  47  by welding or the like. 
     As shown in  FIGS. 5 to 8 , the left cover  25  is supported by and fixed to the lateral support plate  49  of the support frame  43  through a mounting bracket  53  or the like. The right inner wall cover  26  is supported and fixed to the lateral support plate  49  through a mounting bracket or the like. The right cover  28  is supported by the longitudinal support plate  50  of the support frame  43  through a hinge, in such a manner that the right cover  28  is freely opened and closed about a shaft extending in the longitudinal direction. The upper wall  33  of the front cover  22  is positioned right above the lateral support plate  49 , and fixed to the lateral support plate  49  with fixtures, such as bolt and nut. 
     As shown in  FIGS. 6 to 8 ,  13  and  16 , a plurality of fixing pieces  59  protrude rearward from the lateral support plate  49 , and are arranged at predetermined intervals in the transversal direction. Each of these fixing pieces  59  includes a mounting base  59   a  which is a horizontal front side portion, and an inclined fixing portion  59   b  which is a rear side portion sloping upward toward the rear. A rear portion of the upper wall  33  of the front cover  22  is positioned above the fixing pieces  59 , and a rear end portion of the upper wall  33  is fixed to the inclined fixing portions  59   b  with fixtures  60 , such as bolt. It should be noted that the rear end portion of the upper wall  33  is formed as an inclined part  33   a  sloping upward toward the rear so as to correspond to the slope of the inclined fixing portion  59   b.    
     As shown in  FIGS. 5 and 13 , a partition cover  62  is fixed to the right-rear leg  47  of the support frame  43 , so as to, extend along a right end (free end in the transversal direction) of the rear cover  24 . The partition cover  62  is configured to separate a space around the radiator  15  into an upstream-side space and a downstream-side space in terms of an air flow direction. The partition cover  62  separates a space on a rear side of the radiator  15  into a right space and a left space, by extending along a rear portion of a periphery of the radiator  15 . With respect to separation of other spaces around the radiator  15 , i.e., spaces on a front side, on a right side and on a left side, other partition covers or the like (not shown) are used. 
     As shown in  FIGS. 5 ,  7 ,  8 ,  11  and  12 , the rear cover  24  includes: a cover main body  64 ; and an upper cover body  65  fixed to an upper end portion of the cover main body  64  in such a manner that the upper cover body  65  protrudes frontward. The cover main body  64  includes: a rear wall  64   a ; and a mounting rim  64   b  frontward protruding from an upper end of the rear wall  64   a . The rear wall  64   a , when seen from above, is curved in a shape of an arc with an intermediate portion in the transversal direction swelling rearward and a right and left end portions jutting frontward. At the same time, an upper portion of the rear wall  64   a  is curved frontward. The upper cover body  65  includes: an upper wall  65   a ; a pair of right and left side walls  65   b  extending downward from corresponding lateral ends of the upper wall  65   a ; and a rear wall  65   c  extending downward from a rear end of the upper wall  65   a . A rear portion (rear wall  65   c ) of the upper cover body  65  is mounted on the mounting rim  64   b  of the cover main body  64  and fastened with fastenings, such as bolt, in such a manner that the upper cover body  65  is detachable from the cover main body  64 . 
     As shown in  FIGS. 7 to 10  and  12 , on an inner face of a left end portion of the cover main body  64  (the rear cover  24 ), a mounting member  68  in a square U-shape is provided, with an opening thereof facing the cover main body  64 . To the mounting member  68 , a supporting member  69  is fixed with fixtures, such as bolt. To a protruding end of the supporting member  69 , a pair of upper and lower support cylinders  70  are attached. On a left end portion of the lateral support plate  49 , a squared U-shaped support bracket  72  is provided while protruding rearward from the lateral support plate  49 , to which an upper support  73  is fixed with fixtures, such as bolt. The upper support  73  is connected to a connecting body  75  through a lower support  74 . Between the upper support  73  and the lower support  74 , a vertical shaft  77  is provided. The vertical shaft  77  is inserted into the pair of upper and lower support cylinders  70  relatively rotatably about a shaft center thereof. With this configuration, the rear cover  24  is supported by the support frame  43  in such a manner that the rear cover  24  is freely opened and closed about the vertical shaft  77  as a fulcrum shaft on a left end of the rear cover  24  (hereinafter, frequently referred to as “open-close cover  24 ”). 
     On an inner face of a right end portion of the rear cover  24 , a lock mechanism  79  is provided. The lock mechanism  79  is configured to be automatically engaged with an engaging portion provided on the support frame  43  when the rear cover  24  is closed, in such a manner that the rear cover  24  is releasably held in a locked state. 
     As shown in  FIGS. 11 and 12 , from the upper wall  65   a  of the upper cover body  65  (the rear cover  24 ), a cover piece  81  protrudes frontward. On the cover piece  81 , a suspended piece  82  is provided that protrudes downward from a base portion of the cover piece  81 . On the upper wall  33  of the front cover  22  (an upper end of the inclined part  33   a  of the upper wall  33 ), a standing piece  83  is provided that stands opposite to the suspended piece  82 , when the rear cover  24  is closed. The standing piece  83  is positioned below the cover piece  81 , when the rear cover  24  is closed. On the suspended piece  82 , a sealing member  84  is attached so as to be brought into contact with the standing piece  83 , when the open-close cover  24  is closed. The sealing member  84  spans a nearly entire length of the rear cover  24  in the transversal direction. In addition, the sealing member  84  includes a fixing portion  85  having a U-shaped cross-section and a cylindrical contacting portion  86 , with the fixing portion  85  being fitted onto and fixed to a lower portion of the suspended piece  82  from a bottom side. The sealing member  84  is configured to make a seal between an upper end portion of the rear cover  24  and an upper end portion of the front cover  22  along a nearly entire length in the transversal direction, by pressing and bringing the contacting portion  86  of the sealing member  84  into a close contact with the standing piece  83 , when the rear cover  24  is closed. 
     On a protruding end portion (front end portion) of the cover piece  81 , there is provided a downward protrusion  87  in such a manner that the standing piece  83  is positioned below the cover piece  81  and on a suspended piece  82  side (rear side) relative to the downward protrusion  87 , when the rear cover  24  is closed. 
     The cover piece  81  protrudes frontward further in the longitudinal direction than a front end of the sealing member  84 , or protrudes frontward to approximately the same level in the longitudinal direction as the front end of the sealing member  84 . When the rear cover  24  is closed and the sealing member  84  is elastically deformed rearward relative to the cover piece  81  by being pressed to the upper end portion (the standing piece  83 ) of the front cover  22 , the cover piece  81  is located above the sealing member  84  and reaches a position above the upper wall  33  of the front cover  22  (the standing piece  83  or the rear end portion of the upper wall  33 ). 
     On a free end portion of the upper cover body  65  (a lower end portion of a right side wall  65   b ), there is provided an upper sealing member  90  which is brought into contact with a top wall  62   a  of the partition cover  62  when the rear cover  24  is closed, while on a free end portion of the cover main body  64  (the right end portion of the rear wall  64   a ), there is provided a rear sealing member  88  which is brought into contact with a rear wall  62   b  of the partition cover  62  through a protrusion  89  when the rear cover  24  is closed. On a base end portion of the cover main body  64  (left end portion of the rear wall  64   a ), a base end sealing member  91  is provided through a protrusion  92 , which is configured to be brought into contact with a right end portion of the left cover  25  when the rear cover  24  is closed, to thereby make a seal between the left cover  25  and the rear cover  24 . 
     As shown in  FIGS. 1 ,  14  and  15 , on a left upper portion of the counter weight  11 , an opening window  95  is provided at a position corresponding to a position of the hydraulic pump  16 , and a cover member  96  for closing the opening window  95  is detachably provided on the counter weight  11  with a fastening  97 , such as bolt. Accordingly, when the hydraulic pump  16  is to be removed from the swivel stage  2  for the purpose of inspection or the like, it is not necessary to remove the entire counter weight  11 , and simply removing the cover member  96  will suffice. It should be noted that the cover member  96  is made of synthetic resin or the like. 
     According to the above-described embodiment, when the rear cover  24  is rotated about the vertical shaft  77  to close the rear cover  24 , the sealing member  84  on the upper cover body  65  is pressed and brought into a close contact with the standing piece  83  on the front cover  22 , to thereby make a seal between the upper end portion of the rear cover  24  and the upper end portion of the front cover  22  along a nearly entire length in the transversal direction. In this situation, the standing piece  83  is positioned below the cover piece  81  and on the suspended piece  82  side (rear side) relative to the downward protrusion  87 , and the cover piece  81  is located above the sealing member  84  and reaches a position above the upper wall  33  of the front cover  22  (a standing piece  83  or rear end portion of the upper wall  33 ). Therefore, even when it snows on the rear bonnet  36 , or even when soil lifted during excavation work or the like drops on the rear bonnet  36 , the cover piece  81  and the downward protrusion  87  can protect an upper side of the sealing member  84 , and thus prevent snow and soil from accumulated on the sealing member  84 . Accordingly, snow or soil is prevented from being accumulated on the sealing member  84  or portions of the cover in the vicinity thereof, and thus the sealing member  84  and portions of the cover in the vicinity thereof are prevented in advance from becoming fixed in an attached state which may otherwise be caused by frozen snow or soil. 
     In addition, when the rear cover  24  is closed, the upper sealing member  90  on the free end portion of the upper cover body  65  (a lower end portion of a right side wall  65   b ) is brought into contact with the top wall  62   a  of the partition cover  62 , and at the same time, the rear sealing member  88  on the free end portion (a right end portion of a rear wall) of the cover main body  64  is brought into contact with the rear wall  62   b  of the partition cover  62 , to thereby make a seal between the rear cover  24  and the partition cover  62 . The base end sealing member  91  on the base end portion of the cover main body  64  (left end portion of the rear wall  64   a ) is brought into contact with the right end portion of the left cover  25 , to thereby make a seal between the left cover  25  and the rear cover  24 . 
       FIG. 16  shows another embodiment in which the sealing member  84  is provided on an upper end portion of the standing piece  83  of the front cover  22 . When the rear cover  24  is rotated about the vertical shaft  77  to close the rear cover  24 , the sealing member  84  on the standing piece  83  is pressed and brought into a close contact with the suspended piece  82  on the rear cover  24 , to thereby make a seal between the upper end portion of the rear cover  24  and the upper end portion of the front cover  22  along a nearly entire length in the transversal direction. In this situation, the standing piece  83  is positioned below the cover piece  81  and on the suspended piece  82  side (rear side) relative to a tip portion  81 A of the cover piece  81 , and the cover piece  81  is located above the sealing member  84  and reaches a position above the upper wall  33  of the front cover  22  (the standing piece  83  or the rear end portion of the upper wall  33 ). Other features are substantially the same as those described in the above-mentioned embodiment, and thus the descriptions are omitted. 
     It should be noted that, in the above-described embodiments illustrated in  FIGS. 11 and 16 , the cover piece  81  protrudes from the upper wall  65   a  of the open-close cover  24 , so as to be located above the sealing member  84  and reach a position above the upper wall  33  of a fixed cover  22 , when the open-close cover  24  is closed. Accordingly, when the rear bonnet  36  is seen from behind, a step between the open-close cover  24  and the fixed cover  22  is covered with the cover piece  81  and the like, which makes a shape of the rear bonnet  36  simpler and contributes to an excellent appearance. Instead, the cover piece  81  may protrude from the upper wall  33  of the fixed cover  22 , so as to be located above the sealing member  84  and reach a position above the upper wall  65   a  of the open-close cover  24 , when the open-close cover  24  is closed. 
     Also in the above-described embodiments illustrated in  FIGS. 11 and 16 , the cover piece  81  is provided on the upper wall  65   a  of the open-close cover  24 , the suspended piece  82  downward protrudes from the base portion of the cover piece  81 , and the standing piece  83  is provided on a rear end portion of the upper wall  33  of the fixed cover  22 , that stands opposite to the suspended piece  82 . Instead, the cover piece  81  may be provided on the upper wall  33  of the fixed cover  22 , the suspended piece  82  may downward protrude from the base portion of the cover piece  81 , and the standing piece  83  is provided on a front end portion of the upper wall  65   a  of the open-close cover  24 , that stands opposite to the suspended piece  82 . In addition, in this case, the sealing member  84  may be attached to the suspended piece  82 , or alternatively, to the standing piece  83 . 
     Moreover, in the embodiments described above, the rear cover  24  to be opened and closed is supported openably and closably about the vertical shaft  77  as a fulcrum shaft on the left end portion in the transversal direction of the rear cover  24 . Instead, the rear cover  24  to be opened and closed may be supported openably and closably about the vertical shaft  77  as a fulcrum shaft on the right end portion in the transversal direction. 
     Also in the embodiments described above, the front cover  22  is a fixed cover and the rear cover  24  is an open-close cover, and when the rear cover  24  is closed, the upper end portion of the rear cover  24  is brought into contact with the upper end portion of the front cover  22  through the sealing member  84 . However, the fixed cover is not limited to the front cover  22 , and the open-close cover is not limited to the rear cover  24 . For example, the left cover  25  may be a cover to be opened and closed, and the front cover  22  may be a cover to be fixed. In this case, the left cover  25  is made openable and closable about the vertical shaft  77 , to thereby bring an upper end portion of the left cover  25  into contact with the upper end portion of the front cover  22  through the sealing member  84 , when the left cover  25  is closed.