JP2016007665A - Grinder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grinder which certainly prevents the rotation of a wheel guard as compared with a conventional one.SOLUTION: A spring receiving member 42 is positioned between a cylindrical portion 45 and a lead wall portion 41 of a wheel guard 30. A screw shaft portion 44a of a screw 44 is screwed with a screw hole 42a of the spring receiving member 42, and a tip end of the screw 44 projects out to the inside of the cylindrical portion 45. The spring head portion 44c is positioned on the outside of the lead wall portion 41. Between the lead wall portion 41 and the spring receiving member 42, a spring 43 is provided so as to rotate around the spring 44. The spring 43 energizes the spring receiving member 42 toward a center shaft side of the cylindrical portion 45. The tip end of the screw 44 projecting out to the inside of the cylindrical portion 45 is fitted with a recessed portion of a packing gland, thereby preventing the wheel guard 30 from rotating about the packing gland. If a user has, for example, a screw head portion 44c to pull the screw 44, the tip end of the screw 44 is retracted from the recessed portion of the packing gland to release the rotation-preventing.

Description

  The present invention relates to a grinder that performs operations such as grinding with a rotary tool such as a grindstone.

  The grinder includes a spindle that is rotationally driven by a prime mover such as a motor. Various rotary tools are attached to the spindle according to the purpose and application. The rotary tool is, for example, a disk-shaped grindstone, a brush, or a cutter. The grindstone includes a grinding grindstone and a cutting grindstone. The brush includes a wire brush and a wireless brush. The cutter includes a diamond cutter. Various rotary tools attached to the spindle are also collectively referred to as “wheels”. The grinder is required to be equipped with a wheel guard that covers more than half of the outer periphery of the rotating tool (wheel). The rotation position of the wheel guard needs to be changeable according to the type of work.

  Patent Document 1 relates to a wheel guard for a portable disc grinder, and engages a knob penetrating a set ring of the wheel guard with a recess on the outer peripheral surface of the mounting portion on the main body side, thereby preventing the wheel guard from rotating. ing. The knob is held by a cylindrical ring fixed to the outer peripheral surface of the set ring. A spring for urging the knob in a direction retreating from the recess is provided in the cylindrical ring. In the non-rotating state, the pin press-fitted into the knob engages with the holding groove of the cylindrical ring, and the tip of the knob remains engaged with the recess. When releasing the rotation stopper, the knob is rotated to move the pin from the holding groove to the release groove, and the knob is retracted from the recess by the action of the spring.

JP-A-6-328363

  In Patent Document 1, a knob that engages with a concave portion on the outer peripheral surface of the attachment portion on the main body side to prevent rotation is urged by a spring in a direction of retreating from the concave portion. For this reason, if the knob rotates when vibration or impact is applied, there is a possibility that the detent will be released unintentionally due to the bias of the spring.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a grinder in which the wheel guard is more reliably prevented than in the prior art.

One embodiment of the present invention is a grinder. This grinder
Prime mover,
A housing containing the prime mover;
A spindle mounted with a rotary tool and driven to rotate by the prime mover;
A wheel guard covering the rotary tool mounted on the spindle;
A holding member attached to the housing and holding the foil guard;
A detent component that determines the rotational position of the wheel guard relative to the holding member;
Concave portions and convex portions are alternately arranged in the direction around the axis on the outer peripheral surface of the holding member,
The foil guard has a wall having a first through hole or notch that faces any one of the concave or convex portions of the outer peripheral surface of the holding member, and a second through hole that faces the first through hole or notch. Including
The anti-rotation component includes a shaft member that passes through the first through hole or notch and the second through hole, and expands and contracts in conjunction with movement of the shaft member in the axial direction, thereby extending the shaft member to the holding member. And a spring biased toward the side.

  The anti-rotation component includes a spring receiving member having a threaded hole therethrough, the shaft member is a screw that is screwed with the spring receiving member, and the spring includes the wall portion of the wheel guard and the spring. It may be provided between the receiving member.

  The anti-rotation component has a knob member that is provided between the wall portion of the foil guard and the head portion of the screw and is wider than the wall portion, and the screw is held in the axial direction by holding the knob member. It may be pullable.

  The screw may have an extension between the head and the wall.

  When the shaft member is fitted in the concave portion of the outer peripheral surface of the holding member, the wheel guard is prevented from rotating with respect to the holding member, and exceeds the height of the convex portion of the outer peripheral surface of the holding member. When the member is pulled, the foil guard may be rotatable with respect to the holding member.

  The foil guard may have a protrusion that engages with an upper portion of the convex portion of the outer peripheral surface of the holding member and serves as a retaining member from the holding member.

  The foil guard may have a cylindrical portion surrounding an outer peripheral surface of the holding member, and the cylindrical portion may be provided with the first through hole or notch.

  It should be noted that any combination of the above-described constituent elements, and those obtained by converting the expression of the present invention between methods and systems are also effective as aspects of the present invention.

  According to the present invention, it is possible to provide a grinder in which the wheel guard is more reliably prevented than the conventional one.

1 is a side sectional view of a grinder 1 according to Embodiment 1 of the present invention. The principal part disassembled perspective view of the grinder 1 shown in FIG. The top view of the wheel guard 30 of the grinder 1 shown in FIG. FIG. 4 is a plan view of the foil guard 30 and its anti-rotation components in a state where the screw 44 is pulled in FIG. 3 (a state where the spring 43 is compressed to the maximum). AA sectional drawing of FIG. BB sectional drawing of FIG. The side view of the packing land 11 of the grinder 1 shown in FIG. The top view of the wheel guard 30 and its rotation prevention component of the grinder which concerns on Embodiment 2 of this invention. The principal part disassembled perspective view of the grinder which concerns on Embodiment 3 of this invention. The top view of the wheel guard 30 shown in FIG. FIG. 11 is a plan view of the wheel guard 30 and its anti-rotation parts in a state where the screw 44 is pulled in FIG. 10 (a state where the spring 43 is compressed to the maximum).

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or equivalent component, member, etc. which are shown by each drawing, and the overlapping description is abbreviate | omitted suitably. In addition, the embodiments do not limit the invention but are exemplifications, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

Embodiment 1
FIG. 1 is a side sectional view of a grinder 1 according to Embodiment 1 of the present invention. As shown in FIG. 1, the grinder 1 includes a grindstone wheel 2 as a rotary tool, and is used for a grinding operation for flattening the surface of concrete, stone, or the like. The grinding wheel 2 is a diamond grinding wheel, for example. As the rotary tool, a disc-shaped brush or cutter can be attached in addition to the disc-shaped polishing grindstone or the cutting grindstone. The grinder 1 includes a housing 3 (for example, made of resin) and a gear case 4.

  The housing 3 has a substantially cylindrical shape as a whole, and an electric motor 6 as a prime mover is accommodated in the housing 3. The electric motor 6 is connected to an external AC power source such as a commercial power source via a power cord 7 drawn from the rear end of the housing 3. A first bevel gear 21 is provided at the front end of the output shaft 6 a of the electric motor 6. The housing 3 is provided with a power switch 5 that switches whether the electric motor 6 is energized.

  The gear case 4 includes a case body 10 (for example, a metal such as an aluminum alloy) and a packing land 11 as a lid member that closes an opening of the case body 10. The packing land 11 is fixed to the case body 10 by, for example, screwing or the like. The packing land 11 serves as a holding member that holds a foil guard 30 described later. The case body 10 is attached to the front end portion of the housing 3. Two bearings (needle bearing 12 and ball bearing 13) are provided inside the gear case 4, and the spindle 20 is rotatably held by these bearings. The spindle 20 is orthogonal to the output shaft 6 a of the electric motor 6, and one end of the spindle 20 protrudes outside through the packing land 11. On the other hand, a second bevel gear 22 that meshes with a first bevel gear 21 attached to the output shaft 6 a of the electric motor 6 is provided (attached) at the other end of the spindle 20 located in the gear case 4. The rotation of the electric motor 6 is converted by the first bevel gear 21 and the second bevel gear 22 in the rotation direction by 90 degrees, and the rotation speed is reduced and transmitted to the spindle 20. That is, the spindle 20 is rotationally driven by the electric motor 6.

  The grindstone wheel 2 is fixed to the spindle 20 by a wheel washer and a lock nut, and rotates integrally with the spindle 20. When the power switch 5 provided in the housing 3 is operated, electric power is supplied to the electric motor 6 and the output shaft 6a of the electric motor 6 rotates. Then, the spindle 20 connected to the output shaft 6a via the first bevel gear 21 and the second bevel gear 22 rotates, and the grindstone wheel 2 fixed to the spindle 20 rotates.

  A wheel guard 30 is attached to the gear case 4 so as to cover at least 1/2 of the outer periphery of the grinding wheel 2. The wheel guard 30 is prevented from rotating during operation so that its rotation position does not change, and the rotation position can be changed in accordance with the work contents by releasing the rotation prevention. Hereinafter, the mounting configuration of the wheel guard 30 will be described in detail.

  FIG. 2 is an exploded perspective view of a main part of the grinder 1 shown in FIG. FIG. 3 is a plan view of the wheel guard 30 and its anti-rotation parts of the grinder 1 shown in FIG. FIG. 4 is a plan view of the wheel guard 30 and its anti-rotation parts in which the screw 44 is pulled (the spring 43 is compressed as much as possible) in FIG. 5 is a cross-sectional view taken along the line AA in FIG. 6 is a cross-sectional view taken along the line BB in FIG. FIG. 7 is a side view of the packing land 11 of the grinder 1 shown in FIG.

  In FIG. 2, in addition to the packing land 11 and the foil guard 30, a rotation prevention part that attaches the foil guard 30 to the packing land 11 and prevents the rotation with respect to the packing land 11 is illustrated. The anti-rotation component includes a spring receiving member 42, a spring 43, and a screw 44 as a shaft member. The spring receiving member 42 is, for example, a metal plate having a threaded hole 42a. The spring 43 is, for example, a compression coil spring. The screw 44 includes a screw shaft portion 44a, a cylindrical portion 44b, and a screw head portion 44c. A cylindrical portion 44b is interposed between the screw shaft portion 44a and the screw head portion 44c. The cylindrical portion 44b has a larger diameter than the screw shaft portion 44a and a smaller diameter than the screw head portion 44c.

  The wheel guard 30 is a cylinder as a cylindrical part that covers at least half or more of the outer periphery of the grinding wheel 2 and a cylindrical part that is connected to the inner peripheral part of the cover part 31 and faces the outer peripheral surface 14 of the packing land 11. Part (ring part) 45. A first through hole 45 a is provided at a predetermined position of the cylindrical portion 45. A pair of projections 40 projecting inward (center axis side) is provided at the upper end of the cylindrical portion 45. The pair of protrusions 40 are in a positional relationship in which rotational positions differ from each other by about 180 °. A lead wall portion 41 having a second through hole 41 a facing the first through hole 45 a is erected on the upper surface of the cover portion 31.

  The packing land 11 has an outer peripheral surface 14 that faces the inner peripheral surface of the cylindrical portion 45 of the wheel guard 30. The outer peripheral surface 14 is a shape obtained by adding irregularities to the cylindrical side surface shape, and convex portions 14a and concave portions 14b are alternately arranged in the direction around the axis. The upper part of the convex part 14 a is a locking part (recessed part) 15 that locks the protruding part 40 of the foil guard 30. The width of the recess 14b is the same as or slightly larger than the outer diameter of the tip of the screw shaft 44a.

  As shown in FIGS. 3 and 5, the spring receiving member 42 is positioned between the cylindrical portion 45 of the wheel guard 30 and the lead wall portion 41 in the assembled state. The screw shaft portion 44 a of the screw 44 is screwed into the screw hole 42 a of the spring receiving member 42, and the tip protrudes inside the cylindrical portion 45. As shown in FIG. 5, the cylindrical portion 44 b of the screw 44 passes through the second through hole 41 a of the lead wall portion 41, and the screw head portion 44 c is located outside the lead wall portion 41. A spring 43 is provided between the lead wall portion 41 and the spring receiving member 42 so as to go around the screw 44. The spring 43 biases the spring receiving member 42 toward the central axis side of the cylindrical portion 45.

  As shown in FIGS. 4 and 6, when the user holds the screw head 44 c and pulls the screw 44, for example, the spring receiving member 42 with which the screw shaft portion 44 a is screwed also retracts from the cylindrical portion 45 together with the screw 44. The spring 43 provided between the lead wall 41 and the spring receiving member 42 is compressed. When the screw 44 is pulled, the tip of the screw 44 does not protrude to the inside of the cylindrical portion 45 (the tip of the screw 44 exceeds the height of the convex portion 14a), but the spring 43 contracts even if the screw 44 is pulled fully. By preventing further compression, the tip of the screw 44 cannot be removed from the first through hole 45 a of the cylindrical portion 45. When the user stops pulling the screw 44, the screw 44 advances by the elastic force of the spring 43, and the tip of the screw 44 protrudes inside the cylindrical portion 45 again.

  When the foil guard 30 is attached to the packing land 11, first, the foil guard 30 is attached to the packing land 11 while pulling the screw 44 in a state where the protrusions 40 of the wheel guard 30 and the recesses 14 b of the packing land 11 are aligned. Slide it up. Then, the protrusion 40 passes through the recess 14b and reaches the same height as the locking part 15, and the tip of the screw 44 faces the outer peripheral surface of the protrusion 14a. Further, the inner peripheral surface of the cylindrical portion 45 of the wheel guard 30 is close to or in contact with the outer peripheral surface of the convex portion 14 a of the packing land 11. Next, pulling the screw 44 is stopped, and the wheel guard 30 is rotated. Then, the tip of the screw 44 is fitted (engaged) with the recess 14 b of the packing land 11, and the wheel guard 30 is prevented from rotating with respect to the packing land 11. Further, the protrusion 40 fits into the locking portion 15 at the top of the convex portion 14 a (hangs on the top of the convex portion 14 a), and prevents the foil guard 30 from coming off from the packing land 11. That is, when the wheel guard 30 is prevented from rotating with respect to the packing land 11 (when the tip of the screw 44 is fitted in the recess 14b), the protrusion 40 is engaged with the upper portion of the protrusion 14a. The packing land 11 is prevented from coming out downward. Since the outer diameter of the tip of the screw 44 and the width of the recess 14b are substantially equal, the wheel guard 30 is hardly rattling in the non-rotating state.

  When changing the rotation position of the wheel guard 30, the wheel guard 30 is rotated to the desired rotation position with respect to the packing land 11 while pulling the screw 44, the screw 44 is released, and the tip of the screw 44 is moved to an arbitrary recess 14b. What is necessary is just to make it fit. When removing the wheel guard 30 from the packing land 11, the wheel guard 30 is rotated while pulling the screw 44 to align the protrusion 40 and the recess 14 b, and then the wheel guard 30 can be slid downward from the packing land 11. That's fine.

  According to the present embodiment, the following effects can be achieved.

(1) The spring 43 urges the screw 44 toward the outer peripheral surface 14 of the packing land 11, and the tip of the screw 44 does not easily come out of the recess 14 b even if vibration or impact is applied. 11 is ensured to prevent the wheel guard 30 from rotating with respect to 11. As long as the detent is not released, the protrusion 40 of the foil guard 30 engages with the upper portion (the locking portion 15) of the convex portion 14a of the packing land 11, and the foil guard 30 extends downward from the packing land 11. Since removal is prevented, the reliability of the foil guard 30 is also high.

(2) The number of parts related to the retaining and rotation prevention of the wheel guard 30 with respect to the packing land 11 is small and small with three points of the spring receiving member 42, the spring 43 and the screw 44, which is advantageous for cost reduction and space saving. is there.

(3) By rotating the screw shaft portion 44a with respect to the spring receiving member 42, the relative position of the screw 44 and the spring receiving member 42 can be changed, and the amount by which the screw 44 protrudes from the first through hole 45a. Can be adjusted. For example, when the amount by which the screw 44 protrudes from the first through hole 45a is insufficient, the tip of the screw 44 may not be sufficiently fitted into the recess 14b, which may cause a malfunction in the detent function. At this time, if the spring receiving member 42 is rotated and moved so as to approach the screw head 44c, the amount by which the screw 44 protrudes from the first through hole 45a can be increased. If the amount of protrusion is excessive, the spring 43 is excessively compressed. However, if the spring receiving member 42 is rotated and moved away from the screw head 44c, the screw 44 is passed through the first penetration. The amount protruding from the hole 45a can be reduced. Since the rotation of the spring receiving member 42 is restricted by contact with the wheel guard 30, the amount by which the screw 44 protrudes from the first through hole 45a can be adjusted simply by turning the screw 44. It can be adjusted easily and appropriately.

Embodiment 2
FIG. 8 is a plan view of the wheel guard 30 and its anti-rotation component of the grinder according to Embodiment 2 of the present invention. In the grinder of the present embodiment, the cylindrical portion 44b of the screw 44 is further extended outward from the lead wall portion 41 and the screw head portion 44c is the lead wall portion as compared with that of the first embodiment shown in FIG. It is different in that it is spaced outward from 41 and matches in other points. In addition, the part located between the screw | thread head 44c and the lead wall part 41 among the cylindrical parts 44b respond | corresponds to an extension part. According to the present embodiment, the same effects as those of the first embodiment are obtained, and the screw head 44c is separated from the lead wall portion 41. Therefore, the user pulls the screw 44 with the screw head 44c. Easy (easy to release the detent).

Embodiment 3
FIG. 9 is an exploded perspective view of main parts of a grinder according to Embodiment 3 of the present invention. FIG. 10 is a plan view of the wheel guard 30 and its anti-rotation components shown in FIG. FIG. 11 is a plan view of the wheel guard 30 and its anti-rotation parts in which the screw 44 is pulled (the spring 43 is compressed as much as possible) in FIG. The grinder of the present embodiment is different from that of the first embodiment shown in FIG. 3 and the like in that a knob member 46 is provided between the screw head 44c and the lead wall portion 41. , Otherwise match. The knob member 46 is, for example, a metal plate having a through hole 46a having a smaller diameter than the screw head 44c. The knob member 46 is wider than the screw head portion 44 c and the lead wall portion 41. According to the present embodiment, the same effect as that of the first embodiment is obtained, and the knob member 46 having a width wider than both is provided between the screw head portion 44c and the lead wall portion 41. Is easy to pull the screw 44 by holding the knob member 46 (easy to perform the detent release operation).

  The present invention has been described above by taking the embodiment as an example. However, it is understood by those skilled in the art that various modifications can be made to each component and each processing process of the embodiment within the scope of the claims. By the way. Hereinafter, modifications will be described.

  The first through hole 45a of the cylindrical portion 45 of the wheel guard 30 may be a notch. The shaft member is not limited to the screw 44, and may be another member that can expand and contract the spring in conjunction with movement in the axial direction, for example, a member that integrally has a flange portion for spring reception. In this case, it is conceivable that the lead wall portion 41 is attached to the foil guard 30 by welding or screws. Further, there may be a pair of protrusions 40 provided on the inner side of the cylindrical portion 45, and the number thereof may be an odd number.

1 grinder, 2 grinding wheel, 3 housing, 4 gear case, 5 power switch, 6 electric motor (motor), 6a output shaft, 7 power cord, 10 case body, 11 packing land (holding member), 12 needle bearing, 13 ball Bearing, 14 outer peripheral surface, 14a convex part, 14b concave part, 15 locking part (concave part), 20 spindle, 21 first bevel gear, 22 second bevel gear, 30 wheel guard, 31 cover part, 40 projecting part, 41 lead Wall portion, 41a Second through hole, 42 Spring receiving member, 42a Screw hole, 43 Spring, 44 Screw (shaft member), 44a Screw shaft portion, 44b Column portion, 44c Screw head, 45 Cylindrical portion (ring portion) , 45a First through hole, 46 Knob member, 46a Through hole

Claims (7)

Prime mover,
A housing containing the prime mover;
A spindle mounted with a rotary tool and driven to rotate by the prime mover;
A wheel guard covering the rotary tool mounted on the spindle;
A holding member attached to the housing and holding the foil guard;
A detent component that determines the rotational position of the wheel guard relative to the holding member;
Concave portions and convex portions are alternately arranged in the direction around the axis on the outer peripheral surface of the holding member,
The foil guard has a wall having a first through hole or notch that faces any one of the concave or convex portions of the outer peripheral surface of the holding member, and a second through hole that faces the first through hole or notch. Including
The anti-rotation component includes a shaft member that passes through the first through hole or notch and the second through hole, and expands and contracts in conjunction with movement of the shaft member in the axial direction, thereby extending the shaft member to the holding member. A grinder having a spring biased toward the side.   The anti-rotation component includes a spring receiving member having a threaded hole therethrough, the shaft member is a screw that is screwed with the spring receiving member, and the spring includes the wall portion of the wheel guard and the spring. The grinder of Claim 1 provided between the receiving members.   The anti-rotation component has a knob member that is provided between the wall portion of the foil guard and the head portion of the screw and is wider than the wall portion, and the screw is held in the axial direction by holding the knob member. The grinder of claim 2, wherein the grinder is pullable.   The grinder of claim 2, wherein the screw has an extension between the head and the wall.   When the shaft member is fitted in the concave portion of the outer peripheral surface of the holding member, the wheel guard is prevented from rotating with respect to the holding member, and exceeds the height of the convex portion of the outer peripheral surface of the holding member. The grinder according to any one of claims 1 to 4, wherein when the member is pulled, the foil guard is rotatable with respect to the holding member.   The grinder according to any one of claims 1 to 5, wherein the foil guard includes a protrusion that engages with an upper portion of a convex portion of the outer peripheral surface of the holding member to prevent the holding member from being removed.   The said foil guard has a cylindrical part surrounding the outer peripheral surface of the said holding member, The said 1st through-hole or a notch is provided in the said cylindrical part. The grinder described.