Abstract:
A processing machine including a movable support which can mount either one of a processing part and a workpiece and which can reciprocate between a first position and a second position, and a reciprocating part for reciprocating the movable support. A protective part is provided on the upstream side and/or downstream side of the movable support. The protective part includes at least one protective member with a synthetic resin sheet or a film that can be kept rolled in a free state when tensile force is not applied to the protection member and unrolled when tensile force is applied to the member. The protective member is rolled and unrolled by forward and backward movement of the movable support.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a processing machine such as a grinding machine for grinding the rear surface of a semiconductor wafer or a cutting machine for cutting a semiconductor wafer and to a protective member used to protect required constituent elements in the processing machine. 
     DESCRIPTION OF THE PRIOR ART 
     The above processing machine such as a grinding machine or a cutting machine comprises a movable support means which can reciprocate between a first position and a second position and a reciprocating means for reciprocating the movable support means. There is generally provided a guide means extending in the reciprocating direction of the movable support means, and a to-be-guided means provided on the movable support means is slidably engaged with the guide means so that the movable support means can slide along the guide means. Either one of a processing tool such as a grinding wheel or cutting blade and a workpiece such as a semiconductor wafer is mounted to the movable support means. The processing tool mounted to the movable support means is applied to the workpiece by moving forward and/or backward the movable support means, or the processing tool is applied to the workpiece mounted to the movable support means to make desired processing on the workpiece by means of the processing tool. A typical example of the reciprocating means for reciprocating the movable support means comprises a male screw member extending in the reciprocating direction of the movable support means, a female screw member mounted to the movable support means and screwed with the male screw member, and a motor for turning the male screw member. A circulating ball is generally provided between the male screw of the male screw member and the female screw of the female screw member. The reciprocating means provided with the circulating ball is called “ball thread mechanism”. 
     When the workpiece is processed, namely, ground or cut by the processing tool, swarf is produced. If the swarf is adhered to the male screw member or the guide means, the smooth reciprocation of the movable support means is prevented. To cope with this, a bellows member for covering the male screw member and the guide means is arranged on the upstream side and/or downstream side when seen from the forward moving direction of the movable support means. The bellows member can be formed of cloth such as canvas cloth or a combination of cloth and a metal plate. 
     Therefore, the above bellows member is relatively expensive and the operation of exchanging it is not always easy. 
     SUMMARY OF THE INVENTION 
     It is the principal object of the present invention to provide a novel and improved processing machine which prevents swarf from adhering to constituent elements to be protected such as a male screw member and guide means by means of protective means which can be used in place of a bellows member or in addition to the bellows member, is very inexpensive and can be easily exchanged. 
     It is another object of the present invention to provide a protective member which can be used in place of a bellows member or in addition to the bellows member to protect required constituent elements of a processing machine, is much more inexpensive than the bellows member and can be easily exchanged. 
     The inventor of the present invention has found that the above principal object can be attained by a protective means from at least one protective member formed of a synthetic resin sheet or film which can be kept rolled in a free state that tensile force is not applied and can be unrolled when tensile force is applied. The protective member itself which attains the above object can be formed by rolling a synthetic resin sheet or film and heating it for a predetermined period of time in a state where it is rolled. In this specification, the synthetic resin sheet or film which can be kept rolled in a free state that tensile force is not applied and can be unrolled by applying tensile force is referred to as a “rolled sheet or film”. 
     That is, according to the present invention, there is provided a processing machine comprising a movable support means which can reciprocate between a first position and a second position and a reciprocating means for reciprocating the movable support means, either one of a processing tool and a workpiece being mounted to the movable support means, wherein 
     a protective means including at least one protective member formed of a synthetic sheet or film which can be kept rolled in a free state that tensile force is not applied and unrolled when tensile force is applied is provided on the upstream side and/or downstream side of the movable support means when seen from the forward moving direction from the first position to the second position of the movable support means, and the protective member is unrolled by the forward movement of the movable support member and rolled by the backward movement of the movable support member on the upstream side of the movable support means and/or rolled by the forward movement of the movable support member and unrolled by the backward movement of the movable support member on the downstream side of the movable support means. 
     The protective means is preferably provided on both upstream and downstream sides of the movable support means. In a preferred embodiment, there is generally provided a guide means extending in the reciprocating direction of the movable support means and a to-be-guided means to be slidably engaged with the guide means is provided on the movable support means, the reciprocating means comprises a male screw member extending in the reciprocating direction of the movable support means, a female screw member to be screwed with the male screw member and mounted to the movable support means and a motor for turning the male screw member, the protective means includes a main protective members located opposite to the male screw member and the guide means and two sub-protective members situated on both sides of the male screw member and the guide means, and the male screw member and the guide means are covered by the main protective members and the sub-protective members on three sides. 
     Further, according to the present invention, there is provided a protective member constituted by a synthetic resin or film which can be kept rolled in a free state that tensile force is not applied and can be unrolled when tensile force is applied, as the protective member for attaining the above object. 
     Preferably, the protective member is formed by folding back a synthetic resin sheet or film in two in a lengthwise direction, then rolling it from the folded portion and heating it for a predetermined period of time in a state where it is rolled. When this protective member is used in a processing machine, one end thereof can be fixed to the movable support means and the other end thereof can be fixed to the static member. The protective member may also be formed by fixing one end of a synthetic sheet or film to a support shaft, rolling the synthetic resin sheet or film round the support shaft and heating it for a predetermined period of time in a state where it is rolled. When this protective member is used in a processing machine, the support shaft can be rotatably mounted to the static member or the movable support means and the free end of the protective member can be fixed to the movable support means or the static member. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view showing the whole of a grinding machine which is a preferred embodiment of a processing machine constituted according to the present invention; 
     FIG. 2 is a partial perspective view of part of the grinding machine of FIG. 1; 
     FIGS. 3- a  to  3 - d  are schematic diagrams showing a production pattern of a rolled sheet or film used in the grinding machine of FIG. 1; and 
     FIGS. 4- a  to  4 - d  are schematic diagrams showing a production pattern of a modification example of the rolled sheet or film. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Preferred embodiments of a processing machine constituted according to the present invention will be described in detail with reference to the accompanying drawings. 
     FIG. 1 shows a grinding machine for grinding the rear surface of a semiconductor wafer as a workpiece as a preferred embodiment of the processing machine constituted according to the present invention. The illustrated grinding machine comprises a housing wholly designated by  2 . This housing  2  has a prolonged rectangular parallelepiped main portion  4 . At the rear end of the main portion  4 , an upright wall  6  extending upward and substantially vertically is provided. Two grinding means, that is, a rough grinding means  8   a  and a fine grinding means  8   b  are disposed on this upright wall  6 . The constitution and mounting of the rough grinding means  8   a  and the fine grinding means  8   b  will be described in detail later. 
     Continuing explanation with reference to FIG. 1, a turn table  10  is provided on the top surface of a rear half portion of the main portion  4  of the housing  2 . This turn table  10  is supported pivotably on the center axis extending substantially vertically. The turn table  10  is connected to an appropriate electric motor (not shown) and is turned intermittently at 120° each time as will be described later. Three chuck means  12  are provided on the turn table  10  at equiangular intervals in the peripheral direction. The illustrated chuck means  12  are each formed of a porous disk which is mounted pivotably on the center axis extending substantially vertically. The chuck means  12  are connected to an appropriate electric motor (not shown) and turned at a revolution speed of 5 to 100 rpm. The chuck means  12  are selectively communicated to a vacuum source (not shown) so that the semiconductor wafer mounted on the chuck means  12  is vacuum adsorbed to the chuck means  12  as will be described later. By turning the turn table  10  at 120° intermittently, the chuck means  12  are positioned in a carrying-in/carrying-out area  14 , a rough grinding area  16  and a fine grinding area  18 , sequentially. 
     On the top surface of a front half portion of the main portion  4  of the housing  2  are provided a cassette carrying-in area  20 , a cassette carrying-out area  22 , a carrying unit  24 , a semiconductor wafer receiving means  26  and a cleaning means  28 . On the top surface of an intermediate portion of the main portion  4  of the housing  2  are disposed carrying units  30  and  32 . A cassette C storing a plurality of semiconductor wafers W whose rear surfaces are to be ground is placed on the cassette carrying-in area  20 . A cassette C for storing semiconductor wafers W whose rear surfaces have been ground is placed on the cassette carrying-out area  22 . The carrying unit  24  takes out one semiconductor wafer W from the cassette C placed on the cassette carrying-in area  20 , inverts the semiconductor wafer W and places the inverted semiconductor wafer W on the semiconductor wafer receiving means  26 . The carrying unit  30  carries the semiconductor wafer W placed on the semiconductor wafer receiving means  26  with its rear surface facing up to the top of the chuck means  12  positioned in the carrying-in/carrying-out area  14 . 
     The semiconductor wafer W carried to the top surface of the chuck means  12  with its rear surface facing up is brought to the rough grinding area  16  together with the chuck means  12  by the intermittent rotation of the turn table  10 . In the rough grinding area  16 , the chuck means  12  holding the semiconductor wafer W is turned and the rough grinding means  8   a  is applied to the rear surface of the semiconductor wafer W to roughly grind the rear surface of the semiconductor wafer W. The semiconductor wafer W roughly ground in the rough grinding area  16  is brought to the fine grinding area  18  together with the chuck means  12  by the intermittent rotation of the turn table  10 . In the fine grinding area  18 , the chuck means  12  holding the semiconductor wafer W is turned and the fine grinding means  8   a  is applied to the rear surface of the semiconductor wafer W to finely grind the rear surface of the semiconductor wafer W. Rough grinding by means of the rough grinding means  8  and fine grinding by means of the fine grinding means  8   b  will be described later. Thereafter, the semiconductor wafer W whose rear surface has been finely ground is brought to the carrying-in/carrying-out area  14  together with the chuck means  12  by the intermittent rotation of the turn table  10 . 
     The carrying unit  32  carries the semiconductor wafer W on the chuck means positioned in the carrying-in/carrying-out area  14  to the cleaning means  28 . The cleaning means  28  sprays a cleaning liquid which may be pure water onto the semiconductor wafer W, while it being turned at a high speed, to clean the semiconductor wafer W and dries it. The carrying unit  24  inverts the cleaned and dried semiconductor wafer W again so that the front surface thereof faces up, and carries the semiconductor wafer W into the cassette C placed on the cassette carrying-out area  22 . When all the semiconductor wafers W in the cassette C placed on the cassette carrying-in area  20  are all carried out, the cassette C is exchanged with the next cassette C storing semiconductor Wafers W whose rear surfaces are to be ground. When a predetermined number of semiconductor wafers W are stored in the cassette C mounted on the cassette carrying-out area  22 , the cassette C is carried out and an empty cassette C is mounted. 
     Continuing explanation with reference to FIG.  1  and FIG. 2, guide means  34   a  and  34   b  are disposed to the front side of the above upright wall  6  provided at the rear end of the housing  2 . The guide means  34   a  and  34   b  are composed of a pair of guide rails  36   a  and a pair of guide rails  36   b , respectively. The pair of guide rails  36   a  are fixed to the front side of the upright wall  6  with a space therebetween in the width direction and extend substantially vertically. Similarly, the pair of guide rails  36   b  are fixed to the front side of the upright wall  6  with a space therebetween in the width direction and extend substantially vertically. A sliding block  38   a  constituting a movable support means is mounted on the pair of guide rails  36   a  in a such a manner that it can slide in a vertical direction, and a sliding block  38   b  constituting a movable support means is mounted on the pair of guide rails  36   b  in such a manner that it can slide in a vertical direction. Foot portions  40   a  and  40   b  extending in a vertical direction are formed on both sides in the width direction of the rear surfaces of the sliding blocks  38   a  and  38   b , respectively, and grooves extending in a vertical direction are formed in the foot portions  40   a  and  40   b . The grooves formed in the foot portions  40   a  and  40   b  are slidably engaged with the guide rails  36   a  and  36   b  so that sliding blocks  38   a  and  38   b  can slide along the guide rails  36   a  and  36   b , respectively. Therefore, the grooves formed in the foot portions  40   a  and  40   b  constitute a to-be-guided means which cooperate with the guide rails  36   a  and  36   b  constituting the guide means, respectively. 
     Reciprocating means  42   a  and  42   b  for reciprocating the sliding blocks  38   a  and  38   b  in the upward/downward direction or vertically are provided between the above upright wall  6  and the sliding blocks  38   a  and  38   b , respectively. Describing in more detail, male screw members  48   a  and  48   b  extending substantially vertically are rotatably mounted to the front side of the upright wall  6  by means of mounting pieces  44   a  and  44   b  and mounting pieces  46   a  and  46   b , respectively. A male thread is formed on the peripheral surfaces of the male screw members  48   a  and  48   b . Electric motors  50   a  and  50   b  which may be pulse motors are also mounted on the mounting pieces  44   a  and  44   b  and the output axes of the electric motors  50   a  and  50   b  are connected to the male screw members  48   a  and  48   b , respectively. Female screw members (not shown) having a screw through hole extending vertically are fixed to the center portions of the rear surfaces of the sliding blocks  38   a  and  38   b  and screwed with the male screw members  48   a  and  48   b , respectively. Therefore, when the electric motors  50   a  and  50   b  are rotated in a forward direction, the sliding blocks  38   a  and  38   b  are moved forward or down, and when the electric motors  50   a  and  50   b  are rotated in the reverse direction, the sliding blocks  38   a  and  38   b  are moved backward or up. 
     Continuing explanation with reference to FIG.  1  and FIG. 2, the above rough grinding means  8   a  is mounted to the sliding block  38   a  and the above fine grinding means  8   b  is mounted to the sliding block  38   b . Support portions  54   a  and  54   b  project forward in the sliding blocks  38   a  and  38   b  and casings  56   a  and  56   b  are fixed to the support portions  54   a  and  54   b , respectively. Rotary shafts  58   a  and  58   b  extending substantially vertically are rotatably mounted in the casings  56   a  and  56   b , respectively. Electric motors (not shown) are disposed in the casings  56   a  and  56   b , and the output axes of the electric motors are connected with the rotary shafts  58   a  and  58   b , respectively. Disk-like mounting members  60   a  and  60   b  are fixed to the lower ends of the rotary shafts  58   a  and  58   b  and grinding tools  62   a  and  62   b  are secured to the under surfaces of the mounting members  60   a  and  60   b , respectively. A plurality of arc-shaped grinding members are arranged on the under surfaces of the grinding tools  62   a  and  62   b . The grinding members are advantageously formed by bonding together diamond abrasive grains with an appropriate binder such as a resin bond. When the electric motors provided in the casings  56   a  and  56   b  are energized, the grinding tools  62   a  and  62   b  are rotated at a high speed. 
     To roughly grind the rear surface of the semiconductor wafer W held on the chuck means  12  in the rough grinding area  16 , the chuck means  12  is turned and the grinding tool  62   a  is rotated at a high speed. The sliding block  38   a  is lowered to apply the grinding tool  62   a  to the rear surface of the semiconductor wafer W, and further gradually lowered so that the rear surface of the semiconductor wafer w is roughly ground relatively thick. Similarly, to finely grind the semiconductor wafer W held on the chuck means  12  in the fine grinding area  18 , the chuck means  12  is turned and the grinding tool  62   b  is rotated at a high speed. The sliding block  38   b  is lowered to apply the grinding tool  62   b  to the rear surface of the semiconductor wafer W and further gradually lowered so that the rear surface of the semiconductor wafer W is finely ground relatively thin. 
     Thus, the above-described constitution and function of the illustrated grinding machine are substantially the same as the constitution and function of a grinding machine which is marketed under the trade name of DFG841 from Disco Co., Ltd., for example, and already known to people of ordinary skill in the art. Therefore, a detailed description of the constitution and function is omitted from this specification. 
     Continuing explanation with reference to FIG.  1  and FIG. 2, it is important that protective means for preventing the adhesion of swarf to the male screw members  48   a  and  48   b  and the guide rails  36   a  and  36   b  should be provided on the upstream sides and/or downstream sides when seen from the forward moving direction of the sliding blocks  38   a  and  38   b  constituting the movable support means, that is, on the upper sides and/or lower sides of the sliding blocks  38   a  and  38   b , respectively. In the illustrated grinding machine, protective means  64   a  and  66   a  are provided on the upper side and lower side of the sliding block  38   a  and protective means  64   b  and  66   b  are provided on the upper side and lower side of the sliding block  38   b . Stated more specifically, static members  67   a  and  67   b  for covering the upper ends of the guide rails  36   a  and  36   b  and static members  68   a  and  68   b  for covering the lower ends of the guide rails  36   a  and  36   b  are fixed to the front side of the upright wall  6 . The static members  67   a  and  67   b  are shaped like a rectangular plate with cut-aways formed therein corresponding to the mounting pieces  44   a  and  44   b , and the front end and both side ends thereof are substantially aligned with the front faces and both side faces of the sliding blocks  38   a  and  38   b  in a vertical direction, respectively. The static members  68   a  and  68   b  are also shaped like a rectangular plate with cut-aways formed therein corresponding to the above mounting pieces  46   a  and  46   b , and the front end and both side ends thereof are substantially aligned with the front faces and both side faces of the sliding blocks  38   a  and  38   b  in a vertical direction, respectively. The protective means  64   a  and  64   b  comprise main protective members  70   a  and  70   b  disposed between the front ends of the static members  67   a  and  67   b  and the upper ends of the front faces of the sliding blocks  38   a  and  38   b , and sub-protective members  72   a  and  72   b  disposed between the both side ends of the static members  67   a  and  67   b  and the upper ends of the both sides faces of the sliding blocks  38   a  and  38   b , respectively. The protective means  66   a  and  66   b  comprise main protective members  74   a  and  74   b  disposed between the lower ends of the front faces of the sliding blocks  38   a  and  38   b  and the front ends of the static members  68   a  and  68   b , and sub-protective members  76   a  and  76   b  disposed between the lower ends of the both side faces of the sliding blocks  38   a  and  38   b  and the both side ends of the static members  68   a  and  68   b , respectively. 
     It is important that the main protective members  70   a  and  70   b  and  74   a  and  74   b  and the sub-protective members  72   a  and  72   b  and  76   a  and  76   b  should be formed of a rolled sheet or film, that is, a synthetic resin sheet or film which can be rolled in a free state that tensile force is not applied and can be unrolled when tensile force is applied. Connection rods  78  are fixed to the upper ends and lower ends of the rolled sheets or films constituting the main protective members  70   a  and  70   b , one of the connection rods  78  is fixed to the front ends of the static members  67   a  and  67   b  and the other connection rod  78  is fixed to the upper ends of the front faces of the sliding blocks  38   a  and  38   b  by an appropriate connection means (not shown) so that the one ends of the rolled sheets or films constituting the main protective members  70   a  and  70   b  are fixed to the front ends of the static members  67   a  and  67   b  and the other ends thereof are fixed to the upper ends of the front faces of the sliding blocks  38   a  and  38   b , respectively. Connection rods  80  are also fixed to the upper ends and lower ends of the rolled sheets or films constituting the sub-protective members  72   a  and  72   b , one of the connection rods  80  is fixed to the side ends of the static members  67   a  and  67   b  and the other connection rod  80  is fixed to the upper ends of the side faces of the sliding blocks  38   a  and  38   b  by an appropriate connection means (not shown) so that the one ends of the rolled sheets or films constituting the sub-protective members  72   a  and  72   b  are fixed to the side ends of the static members  67   a  and  67   b  and the other ends thereof are fixed to the upper ends of the side faces of the sliding blocks  38   a  and  38   b , respectively. Connection rods  82  are fixed to the upper ends and lower ends of the rolled sheets or films constituting the main protective members  74   a  and  74   b , one of the connection rods  82  is fixed to the lower ends of the front faces of the sliding blocks  38   a  and  38   b  and the other connection rod  82  is fixed to the front ends of the static members  68   a  and  68   b  by an appropriate connection means (not shown) so that the one ends of the rolled sheets or films constituting the main protective members  74   a  and  74   b  are fixed to the lower ends of the front faces of the sliding blocks  38   a  and  38   b  and the other ends thereof are fixed to the front ends of the static members  68   a  and  68   b . Connection rods  84  are also fixed to the upper ends and lower ends of the rolled sheets or films constituting the sub-protective members  76   a  and  76   b , one of the connection rods  84  is fixed to the lower ends of the side faces of the sliding blocks  38   a  and  38   b  and the other connection rod  84  is fixed to the side ends of the static members  68   a  and  68   b  by an appropriate connection means (not shown) so that the one ends of the rolled sheets or films constituting the sub-protective members  76   a  and  76   b  are fixed to the lower ends of the side faces of the sliding blocks  38   a  and  38   b  and the other ends thereof are fixed to the side ends of the static members  68   a  and  68   b , respectively. 
     The protective means  64   a  and  64   b  covers the male screw member  48   a  and the guide rails  36   a  in three sides, that is, front side and both sides, thereby preventing swarf from adhering to the male screw member  48   a  and the guide rails  36   a  fully reliably. When the sliding block  38   a  is moved forward or down, the rolled sheets or films constituting the main protective member  70   a  and the sub-protective member  72   a  are gradually unrolled by the application of tension force caused by the descent of the sliding block  38   a  and the rolled sheets or films constituting the main protective member  74   a  and the sub-protective member  76   a  are gradually rolled by the release of tensile force caused by the descent of the sliding block  38   a . To the contrary, when the sliding block  38   a  is moved backward or up, the rolled sheets or films constituting the main protective member  70   a  and the sub-protective member  72   a  are gradually rolled by the release of tensile force caused by the ascent of the sliding block  38   a  and the rolled sheets or films constituting the main protective member  74   a  and the sub-protective member  76   a  are gradually unrolled by the application of tensile force caused by the ascent of the sliding block  38   a . Similarly, the protective means  64   b  and  66   b  cover the male screw member  48   b  and the guide rails  36   b  in three sides, that is, the front side and both sides, thereby preventing swarf from adhering to the male screw member  48   b  and the guide rails  36   b  fully reliably. When the sliding block  38   b  is moved forward or down, the rolled sheets or films constituting the main protective member  70   b  and the sub-protective member  72   b  are gradually unrolled by the application of tension force caused by the descent of the sliding block  38   b  and the rolled sheets or films constituting the main protective member  74   b  and the sub-protective member  76   b  are gradually rolled by the release of tensile force caused by the descent of the sliding block  38   b . When the sliding block  38   b  is moved backward or up, the rolled sheets or films constituting the main protective member  70   b  and the sub-protective member  72   b  are gradually rolled by the release of tensile force caused by the ascent of the sliding block  38   b  and the rolled sheets or films constituting the main protective member  74   b  and the sub-protective member  76   b  are gradually unrolled by the application of tensile force caused by the ascent of the sliding block  38   b.    
     FIG. 3 show the production pattern of a preferred embodiment of the rolled sheet or film constituting the main protective members and the sub-protective members. As shown in FIG. 3- a , a prolonged synthetic resin sheet or film  86  is prepared. A preferred example of the synthetic resin sheet or film is a polyester sheet or film having a thickness of 0.03 to 2.0 mm, particularly preferably 0.04 to 0.10 mm. As shown in FIG. 3- b , the synthetic resin sheet or film  86  is folded back in two in a lengthwise direction. As shown in FIG. 3- c , the synthetic resin sheet or film  86  is rolled from the folded portion. The thus rolled synthetic resin sheet or film  86  with both ends unrolled is heated at a predetermined temperature for a predetermined period of time while it is kept rolled. For example, when the synthetic resin sheet or film  86  is a 0.05 mm thick polyester sheet or film, it is heated at a temperature of about 140° C. for about 2 hours. Thereafter, it is gradually cooled at normal temperature. Thus, the synthetic resin sheet or film  86  is permanently set in a rolled state and kept rolled, as shown by a solid line in FIG. 3- d , when tensile force is not applied. When tensile force is applied by pulling both ends thereof, it is unrolled as shown by two-dot chain lines in FIG. 3- d . When tensile force is released, it is returned to a rolled state as shown by the solid line in FIG. 3- d . It should be noted that the rolled sheet or film can be easily produced from an inexpensive material, is much cheaper than a bellows member which has been conventionally used to protect constituent elements of a processing machine and can be easily mounted to a desired site of the processing machine. 
     FIGS. 4 show a production pattern of another embodiment of the rolled sheet or film constituting the main protective members and the sub-protective members. Also in the production process shown in FIGS. 4, as shown in FIG. 4- a , a prolonged synthetic resin or sheet  88  is prepared. This synthetic resin sheet or film  88  is also preferably a polyester sheet or film having a thickness of 0.03 to 2.0 mm, particularly preferably 0.04 to 0.10 mm. As shown in FIG. 4- b , one end of the synthetic sheet or film is fixed to a support shaft  90 . The support shaft  90  may be a rod formed from an appropriate synthetic resin or metal. The diameter of the support shaft  90  is preferably about 2 to 5 mm. As shown in FIG. 4- c , the synthetic sheet or film  88  is rolled round the support shaft  90 . The synthetic resin sheet or film  88  rolled round the support shaft  90  with a free end is heated at a predetermined temperature (for example, about 140° C.) for a predetermined period of time (for example, about 2 hours) while it is kept rolled. Thereafter, it is gradually cooled at normal temperature. Thus, the synthetic resin sheet or film  86  is permanently set in a rolled state and kept rolled round the support shaft  90  as shown by a solid line in FIG. 4- d  when tensile force is not applied. When the support shaft  90  is rotatably held at a predetermined position and tensile force is applied by pulling the free end thereof, the synthetic resin sheet or film  86  is unrolled as shown by a two-dot chain line in FIG. 4- d . When tensile force is released, it is returned to the original state that it is rolled round the support shaft  90  as shown by the solid line in FIG. 4- d . When the rolled sheet or film  88  shown in FIG. 4- d  is used in the grinding machine shown in FIG.  1  and FIG. 2, the support shaft  90  may be rotatably mounted to the static members  67   a  and  67   b  and  68   a  and  68   b  or the sliding blocks  38   a  and  38   b , and the free end of the rolled sheet or film  88  may be fixed to the sliding blocks  38   a  and  38   b , or the static member  67   a  and  67   b  and  68   a  and  68   b.    
     While preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, it should be understood that the invention is not limited thereto and various changes and modifications may be made without departing from the scope and spirit of the invention. 
     For example, in the illustrated embodiment shown in FIG.  1  and FIG. 2, the protective means  64   a  and  64   b  and  66   a  and  66   b  are provided on both the upstream side and downstream side when seen from the forward moving direction of the sliding blocks  38   a  and  38   b  constituting the movable support means, respectively. When there is substantially no possibility that swarf is scattered on the upstream side or downstream side, the provision of the protective means on the upstream side or downstream side can be omitted. In the illustrated embodiment shown in FIG.  1  and FIG. 2, the grinding tools  62   a  and  62   b  which are processing tools are mounted to the sliding blocks  38   a  and  38   b  constituting the movable support means, respectively. The present invention can be applied to a processing machine in which not the processing tools but a workpiece is mounted to the movable support means. Further, in the illustrated embodiment shown in FIG.  1  and FIG. 2, the protective members composed of the rolled sheet or film is used in place of the conventionally used bellows member. If desired, a rolled sheet or film may be used in such a manner to protect the bellows member. In this case, the rolled sheet or film can protect required constituent elements more reliably due to the existence of the bellows member. In addition, the bellows member is protected by the rolled sheet or film, whereby when the rolled sheet or film which is relatively inexpensive and can be mounted easily is exchanged if necessary, the bellows member which is relatively expensive and whose mounting operation is relatively complicated can be used for a prolonged time.