JP2018108645A - Cutting machine - Google Patents

Abstract

A cutting machine with good workability is provided.
A motor 2, a housing 3 for housing the motor, and a cutting blade 6 having an outer edge portion are detachably attached, and an output shaft that is rotationally driven by the motor and a part of the outer edge portion are covered. A protective cover 32 supported by the housing so as to be rotatable between a first position and a second position exposing a part of the outer edge; and the first position from the second position relative to the protective cover. And a biasing member 7 that applies a biasing force so as to rotate to the right, and provides a cutting machine in which the biasing force is constant with respect to the rotation amount of the protective cover.
[Selection] Figure 1

Description

  The present invention relates to a cutting machine having a protective cover.

  As a conventional cutting machine, a configuration including a rotatable protective cover and a spring for biasing the protective cover is known (Patent Document 1).

JP 2004-223775 A

  In the conventional cutting machine, the urging force by the spring increases linearly with respect to the rotation amount of the protective cover. For this reason, the user has to move the cutting machine against a large reaction force caused by the biasing force of the spring and proceed with the machining operation.

  In view of such circumstances, the present invention provides a cutting machine with good operability during work.

  In one aspect of the present invention, a motor, a housing for housing the motor, and a cutting blade having an outer edge portion are detachably attached, an output shaft that is rotationally driven by the motor, and a part of the outer edge portion is covered. A protective cover supported by the housing so as to be rotatable between a first position and a second position exposing a portion of the outer edge, and the second position to the first position with respect to the protective cover; And a biasing member that applies a biasing force so as to rotate, wherein the biasing force is constant with respect to a rotation amount of the protective cover.

  According to the above configuration, the urging force is kept constant regardless of the rotation amount of the protective cover. Therefore, the load for operating the cutting machine is suppressed, and workability is improved.

  The urging member has a spring obtained by processing a long plate material into a spiral shape having an inner peripheral surface rotatably supported with respect to the housing and an outer end connected to the protective cover. A cutting machine according to claim 1 is preferred.

  According to the said structure, the load for operating a cutting machine can be suppressed by simple structure, and the workability | operativity of a cutting machine can be improved.

  It is preferable that the housing has a holder that slidably supports the inner peripheral surface.

  The holder preferably has a cylindrical shape having an outer peripheral portion, and the inner peripheral surface is slidable with respect to the outer peripheral portion.

  According to the said structure, a spring can be supported using the holder of a simple structure by sliding the internal peripheral surface of a spring with respect to a housing.

  It is preferable that the spring has a narrow part having a narrower width than the outer end part.

  According to the said structure, the spring constant in a narrow part can be made smaller than the spring constant of an outer end part. Therefore, the urging force of the spring can be kept constant regardless of the rotation amount of the protective cover, and the workability of the cutting machine is improved.

  It is preferable that the spring has a thin part formed thinner than the outer end part.

  According to the said structure, the spring constant in a thin part can be made smaller than the spring constant of an outer end part. Therefore, the urging force of the spring can be kept constant regardless of the rotation amount of the protective cover, and the workability of the cutting machine is improved.

  The base further includes a base capable of sliding a workpiece processed by the cutting blade, and the protective cover has a front end portion that contacts the workpiece during processing, and the biasing member is The force applied to the processing to continue the processing against the pressing force applied to the workpiece through the front end portion monotonously increases as the sliding amount of the workpiece relative to the base increases. It is preferable.

  According to the above configuration, it is possible to prevent a rapid fluctuation or decrease in the force for operating the cutting machine during work. Therefore, the operability of the cutting machine is improved.

  According to the circular saw, it is possible to provide a cutting machine with good operability during work.

The right view of the circular saw which concerns on embodiment of this invention. Sectional drawing along the II-II line | wire in FIG. 1 of the circular saw which concerns on embodiment of this invention. The left view of the circular saw which concerns on embodiment of this invention. In the drawing, description of the battery pack and the cutting blade is omitted. The (a) right side view and (b) bottom view of a spring in the circular saw in the embodiment of the present invention. (A) Right side view, (b) Top view, (c) Left side view, and (d) Front view of a holder in a circular saw in an embodiment of the present invention. The right view of the circular saw which concerns on a prior art. In the circular saw according to the embodiment of the present invention and the circular saw according to the prior art, (a) the relationship between the rotation angle of the protective cover and the urging force, (b) the relationship between the rotation angle and the pressing force, and ( c) The figure which shows the relationship between a sliding distance and the force required for a process. The figure which showed sequentially the mode of progress of the cutting operation of the circular saw which concerns on embodiment of this invention to (a) thru | or (f). The figure which showed sequentially the mode of progress of the cutting operation of the circular saw concerning a prior art to (a) thru | or (f). (A) Right side view and (b) Bottom view of a spring in a circular saw according to a first modification of the present invention. (A) Right side view and (b) Bottom view of a spring in a circular saw according to a second modification of the present invention.

<Embodiment>
1. Overall Configuration Hereinafter, a circular saw 1 according to a first embodiment of the present invention will be described with reference to FIGS. As shown in FIGS. 1 and 2, the circular saw 1 includes a motor 2, a housing 3, a base 4, an adjustment mechanism 5, a disk-shaped cutting blade 6, and a spring 7.

  For convenience of explanation, the direction of the circular saw 1 is determined based on the viewpoint of the circular saw 1 from the user. Specifically, the vertical and forward / backward directions are determined in the directions indicated by the arrows in FIG. The front side in FIG. 1 is the right side of the circular saw 1, and the back side of the paper is the left side of the circular saw 1. Further, regarding the direction of the components constituting the circular saw 1, in principle, the direction in which the circular saw 1 is arranged is used as a reference.

  In this specification, when referring to dimensions, numerical values, etc., not only dimensions and numerical values that completely match the dimensions and numerical values, but also substantially identical dimensions and numerical values (for example, within the range of manufacturing errors). Case). Similarly, “same”, “perpendicular”, “parallel”, “same”, “match”, “constant”, etc. are also “substantially identical”, “substantially orthogonal”, “substantially parallel”, “substantially flush”, It includes “substantially coincident”, “substantially constant”, and the like.

  The motor 2 is accommodated in the housing 3 as shown in FIG. The motor 2 has a rotating shaft 2A extending in the left-right direction, and includes a pinion 21 fixed to the right end portion of the rotating shaft 2A. The pinion 21 is engaged with a reduction mechanism (not shown) composed of a plurality of gears, and the reduction mechanism (not shown) is engaged with the gear 22 below the pinion 21. The gear 22 is fixed to the left end portion of the output shaft 23 extending left and right, and the cutting blade 6 is detachably attached to the right end portion of the output shaft 23. Specifically, the cutting blade 6 is sandwiched between the washer 24 and the output shaft 23. The washer 24 is fixed by a bolt 25 that is screwed to the output shaft 23.

  With the above configuration, the driving force generated in the motor 2 is transmitted to the cutting blade 6 via the pinion 21, a reduction mechanism (not shown), the gear 22, and the output shaft 23.

  As shown in FIG. 1, the housing 3 forms an outer shell of the circular saw 1 and accommodates the motor 2 and the like. The housing 3 includes a saw cover 31 that covers the upper portion of the cutting blade 6, a protective cover 32 that covers the lower portion of the cutting blade 6, a handle 33, a trigger 34, a gear cover 36 that houses the gear 22 and the output shaft 23, and the motor 2. And a pinion 21, a motor accommodating portion 37 that accommodates a speed reduction mechanism (not shown), and a holder 38. Further, the battery pack P can be attached to and detached from the rear portion of the housing 3.

  The saw cover 31 is disposed on the right side of the handle 33 so as to cover the upper edge of the cutting blade 6. The protective cover 32 is provided so as to cover the rear part and the lower part of the outer edge part of the cutting blade 6. The protective cover 32 is disposed in a nested manner inside the saw cover 31, and is rotatable along the outer edge portion of the cutting blade 6 about the output shaft 23.

  A spring 7 described later is interposed between the protective cover 32 and the saw cover 31, and the spring 7 biases the protective cover 32 against the saw cover 31 in the rotation direction of the cutting blade 6. That is, the protective cover 32 is biased counterclockwise when viewed from the right side. When not working, the protective cover 32 is disposed so as to cover the lower part and the rear part of the outer edge of the cutting blade 6. During the work, the protective cover 32 rotates as the work progresses, and the outer edge of the cutting blade 6 is gradually exposed.

  The handle 33 has a substantially D shape in side view and extends above the motor housing portion 37. The handle 33 extends from the front to the rear so that the user can easily hold it. A trigger 34 that is electrically connected to the motor 2 and is used for driving and stopping the motor 2 is provided below the handle 33.

  The gear cover 36 is disposed on the right side of the motor housing portion 37 (FIG. 2). The lower surface of the gear cover 36 is formed on a substantially flat plate. The gear cover 36 mainly constitutes the right surface of the housing 3 and accommodates the gear 22 and the output shaft 23. From the right end of the gear cover 36, the output shaft 23 projects rightward. The upper end portion of the gear cover 36 is formed on an arc in a side view and is connected to the saw cover 31.

  A holder 38 is attached to the right surface of the gear cover 36 so as to protrude rightward. As shown in FIG. 5, the holder 38 includes a main body portion 38A and a flange portion 38B. The main body portion 38A is a substantially cylindrical member, and a screw hole penetrating the main body portion 38A in the left-right direction is formed inside. The holder 38 is fixed to the gear cover 36 via a screw (not shown). A plate-like flange portion 38B having a diameter larger than that of the main body portion 38A is attached to the right end portion of the main body portion 38A, and prevents a spring 7 described later from shifting in the left-right direction.

  As shown in FIG. 1, the base 4 is a substantially flat plate-like member that extends in the front-rear and left-right directions below the circular saw 1. The lower portion of the base 4 is formed in a substantially flat shape so as to be in contact with the workpiece and to be slidable. The base 4 supports the housing 3 so as to be tiltable about the tilting axis, and the angle of the cutting blade 6 with respect to the base 4 can be adjusted. Further, the base 4 supports the front end portion of the saw cover 31 so as to be swingable via the swing shaft 3A (FIG. 1), so that the protruding amount of the cutting blade 6 from the base 4 can be adjusted. An opening is formed in the right part of the base 4 in the front-rear direction. The cutting blade 6 is arrange | positioned so that it may protrude below through an opening part (FIG. 2). A bevel plate 41 extending upward and an adjustment mechanism 5 are provided on the rear upper surface of the base 4, and a connection plate 42 extending upward is provided on the front upper surface. The bevel plate 41 is a substantially flat member that forms a substantially fan shape when viewed from the front.

  The connection plate 42 is a substantially flat member that forms a substantially sector shape when viewed from the front. The bevel plate 41 and the connection plate 42 are formed with arc-shaped long holes. A butterfly bolt 43 is inserted through the bevel plate 41 in the front-rear direction, and a butterfly bolt 44 is inserted through the elongated hole of the connection plate 42 in the front-rear direction. The user can fix the tilting posture of the housing 3 with respect to the base 4 by operating these two butterfly bolts 43 and 44. Specifically, when the user tightens the two butterfly bolts 43 and 44, the heads of these butterfly bolts are pressed against the bevel plate 41 and the connection plate 42, respectively, and the housing 3 is fixed.

  The adjustment mechanism 5 is a member that forms an arc shape in a side view. The adjustment mechanism 5 is formed with a long hole 5b that penetrates the adjustment mechanism 5 in the left-right direction and forms an arc shape in a side view (FIG. 3). A lower end portion of the adjustment mechanism 5 is rotatably attached to the upper surface of the base 4. The adjustment mechanism 5 is connected to the saw cover 31 via a screw (not shown). Specifically, a screw (not shown) is inserted in the left and right direction into the long hole 5 b and is screwed into the left side surface of the saw cover 31. The user can lock the saw cover 31 to the adjustment mechanism 5 by tightening the top of a screw (not shown) so as to press the adjustment mechanism 5. That is, the adjustment mechanism 5 has a function of changing and holding the swinging posture of the housing 3.

  The spring 7 is arranged around the holder 38 (FIG. 1). As shown in FIG. 4, the spring 7 is a spiral spring obtained by coiling a plate-like long metal member having a uniform thickness and width into a spiral shape. The spiral portion of the spring 7 has an inner peripheral surface 71 (FIG. 4). The inner peripheral surface 71 has a diameter larger than the outer diameter of the main body portion 38A.

  The inner end or the left end of the spring 7 is not connected to the holder 38. Further, the spring 7 is arranged with play so that the inner peripheral surface 71 can slide with respect to the outer peripheral portion of the main body portion 38A. Therefore, the spring 7 can rotate or rotate with respect to the holder 38. The spring 7 is disposed between the flange portion 38B and the gear cover 36, and is prevented from shifting in the left-right direction. The front end 72 that forms the spiral outer end of the spring 7 is attached to the upper end of the protective cover 32 via an attachment member such as an S-shaped hook.

  When the front end portion 72 is pulled forward, the spring 7 applies a biasing force to the protective cover 32 by using a force that the spring 7 tries to restore in a spiral shape. The protective cover 32 is urged by the spring 7 so as to rotate counterclockwise when viewed from the right side. When not working, the spring 7 is attached to the protective cover 32 with the front end portion 72 pulled out by a predetermined length, and exerts a biasing force on the protective cover 32. The front end 72 corresponds to the outer end of the present invention.

  The user performs a cutting operation by pressing and sliding the base 4 on the workpiece W. When the base 4 is slid on the upper surface of the workpiece W, the front end portion of the protective cover 32 comes into contact with the workpiece W, and the protective cover 32 rotates clockwise as viewed from the right side against the urging force. .

  When the protective cover 32 rotates, the front end 72 of the spring 7 is pulled forward. As the rotation amount of the protective cover 32 increases, the pull-out amount of the spring 7 (or the front end portion 72 of the spring 7) increases. Here, since the spring 7 is disposed so as to rotate or circulate with respect to the holder 38, the urging force applied by the spring 7 to the protective cover 32 is held substantially constant regardless of the amount of pull-out. .

2. Prior Art Circular Saw and Spring FIG. 6 shows a conventional circular saw 1A. The same parts as those in the embodiment are denoted by the same reference numerals as those used in the embodiment, and description thereof is omitted.

  In the circular saw 1A according to the prior art, a biasing force is applied to the protective cover 32 using a coil spring 7A. The rear end of the coil spring 7 </ b> A is fixed to the gear cover 36, and the front end 72 is fixed to the protective cover 32. Further, when the rotation angle of the protective cover 32 is 0 (zero) (the state shown in FIG. 6), the coil spring 7A is held in a state where it is pulled by a predetermined amount.

  When the protective cover 32 rotates, the spring 7A is pulled forward. Further, the deformation amount of the spring 7 increases as the rotation amount of the protective cover 32 increases. Here, since the rear end portion of the spring 7 is fixed to the housing 3, the urging force applied by the spring 7 </ b> A to the protective cover 32 increases at a constant rate with respect to the pull-out amount.

3. Comparison with Prior Art (1) Relationship Between Rotation Angle and Biasing Force Relationship between Biasing Force Applied to Protective Cover 32 by Spring 7 According to Embodiment and Spring 7A According to Conventional Technology and Rotation Angle of Protective Cover 32 The graph which shows is shown to Fig.7 (a). In the graph in the figure, the horizontal axis indicates the rotation angle of the protective cover 32, and the vertical axis indicates the urging force applied by the spring 7 to the protective cover 32. The solid line indicates the characteristics of the spring 7 in the present embodiment, and the dotted line indicates the characteristics of the spring 7A according to the prior art.

  As described above, in the embodiment, the urging force that the spring 7 applies to the protective cover 32 is held substantially constant regardless of the amount of the spring 7 pulled out. Therefore, as shown in FIG. 7A, the urging force is substantially constant regardless of the rotation angle of the protective cover 32.

  On the other hand, in the case of the spring 7A according to the prior art, the urging force that the spring 7A applies to the protective cover 32 increases linearly with an increase in the amount of tension of the spring 7A. Therefore, as shown in FIG. 7A, the urging force increases at a constant rate with respect to an increase in the rotation angle of the protective cover 32.

(2) Relationship between rotation angle and pressing force The pressing force that the spring 7 by the circular saw 1 of the embodiment and the spring 7A by the conventional circular saw 1A apply to the workpiece W via the protective cover 32; A graph showing the relationship with the rotation angle of the protective cover 32 is shown in FIG. In the graph of FIG.7 (b), a horizontal axis | shaft shows a rotation angle and a vertical axis | shaft shows pressing force. A white graph indicates the pressing force related to the conventional circular saw 1A (spring 7A), and a hatched graph indicates the pressing force related to the circular saw 1 (spring 7) of the embodiment. The graph shows a tendency that the pressing force is the highest in the vicinity of the rotation angle of 90 degrees and the pressing force is low at the rotation angles of 30 degrees and 120 degrees.

  The reason why the pressing force becomes the highest at the rotation angle of 90 degrees will be described below. FIGS. 8A to 8F sequentially show the displacement of the protective cover 32 in the circular saw 1 according to the embodiment from the rotation angle of 0 to 140 degrees. Further, similar drawings of the conventional circular saw 1A are shown in FIGS. 9 (a) to 9 (f). In each figure, the distance L indicates the vertical distance between the contact point between the workpiece W and the protective cover 32 and the center of the output shaft 23. Note that the center of the output shaft 23 coincides with the rotation center of the protective cover 32.

  When the base 4 slides forward with respect to the workpiece W, the rotation angle of the protective cover 32 increases. At this time, the protective cover 32 and the workpiece W come into contact with each other. As shown in FIGS. 8 and 9A to 9F, the distance L changes according to the rotation angle of the protective cover 32. As shown in FIGS. 8D and 9D, the distance L is small when the rotation angle is 90 degrees or more.

  When the rotation angle exceeds 90 degrees, the protective cover 32 and the workpiece W do not face each other as shown in FIGS. 8 and 9 (e) and (f). Therefore, the pressing force that the spring 7 and the spring 7 </ b> A give to the workpiece W is lower than that at the rotation angle of 90 degrees.

  Here, the pressing force applied to the workpiece W by the spring 7 and the spring 7A is inversely proportional to the distance L between the output shaft 23 that is a fulcrum and the contact point that is the point of action. Therefore, the pressing force is the highest at the rotation angle of 90 degrees in both the circular saw 1 according to the embodiment and the circular saw 1A according to the conventional technique.

  Here, as shown in FIG. 7A, the urging force of the spring 7 according to the embodiment is smaller than the urging force generated by the conventional spring 7A. Therefore, the maximum value of the pressing force in the circular saw 1 according to the embodiment is lower than the maximum value of the pressing force of the circular saw 1A according to the prior art.

  Further, the amount of change in pressing force in the circular saw 1 is smaller than the amount of change in pressing force in the circular saw 1A.

(3) Relationship between the sliding distance and the force applied to the circular saw during the operation The sliding distance of the circular saw 1 and the circular saw 1A and the force required for processing the circular saw 1 and the circular saw 1A during the cutting operation Is shown in the graph of FIG. In the graph of FIG. 7C, the vertical axis indicates the force required to slide the circular saw 1 and the circular saw 1A, and the horizontal axis indicates the sliding distance of the circular saw 1 and the circular saw 1A. Here, the sliding distance refers to the distance that the base 4 has moved forward with respect to the workpiece W during the cutting operation. In the figure, a solid line shows the circular saw 1 according to the embodiment, and a dotted line shows a conventional circular saw 1A.

  In the circular saw 1 and the circular saw 1A, the force required for processing is a force for moving the circular saw 1 and the circular saw 1A forward in the operation of rotating the cutting blade 6 to cut the workpiece W. Say. Therefore, in addition to the above-described pressing force, a friction force between the base 4 and the workpiece W, a load between the cutting blade 6 and the workpiece W, and the like act on the force necessary for the processing. As is apparent from the graph, in the conventional circular saw 1A, the force required for machining increases once, records the maximum load, and then decreases greatly. On the other hand, in the circular saw 1 by embodiment, the force required for a process shows the characteristic that it increases without decreasing with respect to the increase in a sliding distance. That is, the force required for processing the circular saw 1 increases monotonously with respect to the sliding distance.

  As a cause of such a difference, the above-described difference in pressing force acts greatly. That is, in the circular saw 1A according to the prior art, the pressing force greatly increases / decreases with respect to the rotation angle of the protective cover 32, whereas in the circular saw 1 according to the embodiment, the increase / decrease in the pressing force is small (FIG. 7B). )). As a result, the difference in characteristics between the embodiment and the prior art also appears in the force required for processing.

  In the circular saw 1 according to the embodiment, the force required for processing increases monotonously with respect to the sliding distance. As a result, the user can perform the work of the circular saw 1 more smoothly than in the past.

  Specifically, in the conventional circular saw 1A, the pressing force greatly increases / decreases as the sliding progresses. Therefore, the cutting speed changes greatly at the moment when the pressing force starts to decrease, or the cutting direction bends left and right. It was difficult to do so. However, in the circular saw 1 according to the embodiment, the force required for processing increases monotonously with respect to the sliding distance, and thus the force required for processing does not change rapidly. Therefore, it is easy to keep the cutting speed constant, and it is easy to keep the cutting direction straight.

<Modification>
The present invention has been described based on the embodiments. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to combinations of these components and the like, and such modifications are within the scope of the present invention.

  A spring 107 according to a first modification is shown in FIG. The spring 107 is a spiral spring obtained by coiling a plate-like long metal member having a uniform thickness into a spiral shape, basically like the spring 7 according to the embodiment. As a difference from the embodiment, the spring 107 according to the modified example has a narrow width portion 107 </ b> A that is narrower than the front end portion 172. Since the narrow width portion 107A is narrow, the rigidity is lower than that of the front end portion 172. By providing such a section, it is possible to adjust the urging force that the spring 107 applies to the protective cover 32 regardless of the pull-out amount of the spring 107.

  In particular, it is preferable to correspond the narrow width portion 107A in the vicinity of a rotation angle of 90 degrees where a large pressing force is required. In this case, the pressing force can be reduced and a smooth machining operation can be performed.

  A spring 207 according to a second modification is shown in FIG. The spring 207 is basically a spiral spring obtained by coiling a plate-like long metal member having a uniform width into a spiral shape, similarly to the spring 7 according to the embodiment. As a difference from the embodiment, the spring 207 according to the second modified example has a thin portion 207 </ b> A that is thinner than the front end portion 272. Since the thin portion 207A is thinner than the front end portion 272, its rigidity is lower than that of the front end portion 272. By providing such a section, it is possible to adjust the urging force applied by the spring 207 to the protective cover 32 regardless of the amount by which the spring 207 is pulled out. In addition, the dashed-two dotted line in FIG. 11 shows the range of the thin part 207A.

  It is also conceivable to combine the above two modifications and adjust the rigidity in an arbitrary section by simultaneously changing the change in the thickness and width of the spring with respect to the pull-out amount.

  The urging force of the springs 7, 107, and 207 needs to be appropriately adjusted according to the diameters of the springs 7, 107, and 207, the relative position between the holder 38 and the protective cover 32, the distance, and the like. The above-described modification can flexibly respond to such a design requirement, and has an effect of ensuring a large degree of design freedom.

  In the above embodiment, the urging force of the spring 7 is substantially constant with respect to the pull-out amount and the rotation angle of the protective cover 32. However, according to the first and second modified examples, not only is the urging force of the springs 107 and 207 held substantially constant with respect to the pressing force and the pull-out amount and the rotation angle of the protective cover 32. It is also possible to design as a so-called non-linear spring that freely increases and decreases. That is, when the springs 107 and 207 are used, it is possible to flexibly set the pressing force and the force required for processing according to the design requirements.

  In the embodiment and the modification described above, the holder 38 is configured not to rotate with respect to the housing 3 or the gear cover 36. However, the present invention is not limited to this, and the holder 38 may be rotatably attached to the gear cover 36 and may be configured to rotate together with the inner peripheral surfaces 71, 171, 271 of the springs 7, 107, 207.

DESCRIPTION OF SYMBOLS 1 Circular saw 2 Motor 3 Housing 4 Base 3A Oscillating shaft 5 Adjustment mechanism 6 Cutting blade 7, 107, 207 Spring 38 Holder

Claims (9)

A motor,
A housing for housing the motor;
A cutting blade having an outer edge is detachably attached, and an output shaft that is rotationally driven by the motor;
A protective cover supported by the housing so as to be rotatable between a first position covering a part of the outer edge part and a second position exposing a part of the outer edge part;
An urging member that applies an urging force so as to rotate from the second position to the first position with respect to the protective cover;
The cutting machine according to claim 1, wherein the urging force is constant with respect to a rotation amount of the protective cover.   The urging member has a spring obtained by processing a long plate material into a spiral shape having an inner peripheral surface rotatably supported with respect to the housing and an outer end connected to the protective cover. The cutting machine according to claim 1.   The cutting machine according to claim 2, wherein the housing includes a holder that slidably supports the inner peripheral surface. The holder has a cylindrical shape with an outer periphery;
The cutting machine according to claim 3, wherein the inner peripheral surface is slidable with respect to the outer peripheral portion.   The cutting machine according to any one of claims 2 to 4, wherein the spring has a narrow portion having a narrower width than the outer end portion.   The cutting machine according to any one of claims 2 to 5, wherein the spring has a thin part formed thinner than the outer end part. A base capable of sliding a workpiece to be processed by the cutting blade;
The protective cover has a front end portion that contacts the workpiece during processing,
In order to continue the processing against the pressing force that the urging member applies to the workpiece through the front end portion, the force applied to the processing increases the sliding amount of the workpiece with respect to the base. The cutting machine according to any one of claims 1 to 6, wherein the cutting machine monotonously increases with respect to. A motor,
A housing for housing the motor;
A cutting blade having an outer edge is detachably attached, and an output shaft that is rotationally driven by the motor;
A protective cover supported by the housing so as to be rotatable between a first position covering a part of the outer edge part and a second position exposing a part of the outer edge part;
An urging member that applies an urging force so as to rotate from the second position to the first position with respect to the protective cover;
The biasing member is configured by a spring obtained by processing a long plate material into a spiral shape having an inner peripheral surface rotatably supported with respect to the housing and an outer end connected to the protective cover. A cutting machine characterized by that. 9. The cutting machine according to claim 8, wherein the urging force is constant with respect to a rotation amount of the protective cover.

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