CN221392802U - Nib thickness regulating mechanism of hand pencil sharpener - Google Patents

Abstract

The utility model provides a nib thickness adjusting mechanism of a hand pencil sharpener, and belongs to the technical field of pencil sharpeners. The pen point thickness adjusting mechanism of the hand pencil sharpener comprises a cutter rest and a crank, wherein an installation cavity is formed in the crank, a guide hole is formed in the rear end of the cutter rest, the hand pencil sharpener comprises a push rod penetrating through the guide hole and an adjusting head, the front end of the adjusting head is located in the installation cavity, the rear end of the adjusting head stretches out of the crank, the adjusting head is connected with the crank in a sliding mode along the front-back direction, the adjusting head can rotate relative to the crank, the rear end of the push rod is provided with a guide head, the installation cavity is internally provided with a guide slope which is arc-shaped and is arranged around the center line of the guide hole, the guide slope is provided with a plurality of positioning grooves, the side part of the front end of the adjusting head can move along the guide slope and can be clamped into a lug in any one of the positioning grooves when the adjusting head rotates, and the guide head abuts against the front end of the adjusting head and can stretch into the guide hole when the adjusting head moves forwards. It has the advantages of good broken core pushing effect, wide applicability and the like.

Description

Nib thickness regulating mechanism of hand pencil sharpener

Technical Field

The utility model belongs to the technical field of pencil sharpener, and relates to a hand pencil sharpener.

Background

Hand pencil sharpener is a common pencil sharpener, and a user can finish the planing of pencils by shaking the handle. In different use environments, different requirements are required on the thickness of the pen point of the pencil, and therefore, the hand-operated pencil sharpener is required to have the pen point thickness adjusting function so as to meet the requirements of users. For example, a nib thickness adjusting mechanism of a pencil sharpener with the patent application number 201921681487.9 comprises a knife rest, a hand crank, a push rod and an adjusting structure, wherein the knife rest is arranged at the front end of the hand crank and is fixed through a gear ring; the adjusting structure comprises a button, a connecting cylinder and an adjusting knob, wherein the adjusting knob is sleeved outside the button and connected with the button through the connecting cylinder, the adjusting structure can drive the button to synchronously rotate, the adjusting structure is rotatably arranged at the rear end of a handle through a rear cover, the button is of a cap-shaped structure with an open front end, a stop block is arranged on one side of the inner wall of the button, the rear end of a push rod is an expanding section, the rear end of the push rod is inserted into the button and props against the stop block, a spring is sleeved in the middle of the push rod and supported between the inner wall of a tool rest and the expanding section of the push rod, the push rod has a trend of always moving backwards and propping against the stop block of the button, the connecting cylinder is a round sleeve with a front opening and a rear opening, the inner diameter of the connecting cylinder is matched with the outer diameter of the button, at least two corresponding positioning ribs are axially arranged on the inner wall of the connecting cylinder, and the button is inserted into the connecting cylinder and positioned through the cooperation of the positioning ribs and the groove, and can axially move forwards and backwards along the groove.

When the pen point adjusting device is used, the adjusting knob is rotated according to the thickness requirement of the pen point, the connecting cylinder is driven to link the button to rotate, and the stop dog is abutted against tile-shaped structures with different heights of the push rod, so that the axial movement stroke of the push rod is adjusted, the depth of the pen point extending into the tool rest is limited, and the thickness adjustment of the pen point is realized; when the broken core needs to be cleaned, the push rod can be pushed inwards only by pressing the button inwards, the broken core is pushed out, and the button can be reset under the action of the spring after being loosened. Through the arrangement, the nib thickness adjusting mechanism of the pencil sharpener not only has a nib thickness adjusting function, but also has a broken core pushing function.

However, in the nib thickness adjusting mechanism of the pencil sharpener described above, in order to provide the tile-shaped structure on the push rod and provide the enlarged diameter section at the rear end of the push rod, the enlarged diameter section is larger in size than the hole in the cutter holder through which the push rod passes, which results in that the distance that the push rod can actually move in the axial direction is only the remaining space inside the connecting cylinder (which can be obtained unambiguously from fig. 1 of the specification thereof), that is, the distance that the broken core can be actually obtained is short, and therefore, there is a problem that the broken core pushing effect is not ideal while the applicability is improved.

Disclosure of utility model

The utility model aims at solving the problems existing in the prior art, and provides a nib thickness adjusting mechanism of a hand pencil sharpener, which solves the problem that the broken core pushing effect is not ideal while the applicability is improved.

The aim of the utility model can be achieved by the following technical scheme:

The pen point thickness adjusting mechanism of the hand pencil sharpener comprises a cutter rest and a crank fixedly connected to the rear end of the cutter rest, wherein an installation cavity is formed in the crank, a guide hole communicated with the installation cavity is formed in the rear end of the cutter rest, the pen point thickness adjusting mechanism comprises a push rod penetrating through the guide hole and an adjusting head, the front end of the adjusting head is located in the installation cavity, the rear end of the adjusting head extends out of the crank, the adjusting head and the crank are in sliding connection in the front-back direction, the adjusting head can rotate relative to the crank, a spring with elasticity is arranged in the guide hole and acts on the push rod backwards, a guide head in clearance fit with the guide hole is arranged at the rear end of the push rod, the crank is characterized in that a guide slope which is arc-shaped and is arranged around the center line of the guide hole is arranged in the installation cavity, a plurality of positioning grooves are formed in the guide slope, the side part of the front end of the adjusting head is provided with lugs which can move along the guide slope and can be clamped into any positioning groove when the adjusting head rotates, and the front end of the adjusting head abuts against the front end of the adjusting head and can extend into the guide hole when the adjusting head moves forwards.

The tip of the shaved pencil is the thinnest in this case with the lugs positioned in the positioning grooves of the distance guides Kong Zuiyuan as an initial state. If the pencil point of the shaved pencil is thicker, the user only needs to rotate the adjusting head to enable the lugs to move along the guide slope, and the adjusting head is forced to move forwards by means of the gradient of the guide slope when the lugs move along the guide slope because the guide surface is arc-shaped and is arranged around the center line of the guide hole, so that the push rod can be pushed forwards by the adjusting head, and the push rod moving forwards is positioned after the lugs are clamped into the corresponding positioning grooves. When the pencil is broken in the planing process, a user only needs to press the adjusting head forwards, and the adjusting head can directly push the push rod to move forwards and push out the broken pencil.

In the nib thickness adjusting mechanism of the hand pencil sharpener, lugs are arranged at the side part of the front end of the adjusting head and are matched with a guide slope which is arc-shaped and is arranged around the center line of the guide hole in the installation cavity of the crank, so that the rear end of the pushing rod does not need to go to an expanding section with the size larger than that of the guide hole, and then the front end of the adjusting head is arranged in the guide hole when the adjusting head moves forwards in a combined mode, so that the distance for pushing broken cores is increased, and the nib thickness adjusting mechanism of the hand pencil sharpener has the nib thickness adjusting function and the broken core pushing function to improve applicability and simultaneously has an ideal broken core pushing effect.

In the nib thickness adjusting mechanism of the hand pencil sharpener, the adjusting head is columnar and is arranged concentrically with the guide hole, the center position of the front end part of the adjusting head is provided with the abutting part, and the outer size of the abutting part is smaller than that of the guide hole.

By arranging the abutting part at the center of the front end part of the adjusting head, the outer dimension of the abutting part is smaller than that of the guide hole, so that the adjusting head can always move forward until the abutting part stretches into the guide hole of the tool rest to increase the distance of pushing out the broken core when the breaking core pushing-out action is executed.

In the nib thickness adjusting mechanism of the hand pencil sharpener, the rear end of the adjusting head is provided with an external hexagonal operating part.

The arrangement of the operation part enables a user to rotate the adjusting head to adjust the thickness of the pen point more easily.

In the nib thickness adjusting mechanism of the hand pencil sharpener, the crank comprises a handle body with a notch at the rear side and a rear cover detachably connected in the notch, an inner cavity is formed between the handle body and the rear cover, the rear cover is provided with a through hole for the operation part to extend out, and the guide slope is arranged at the front side of the rear cover.

The arrangement makes the production and manufacture simpler, and especially the arrangement of the guide slope surface is easier.

In the nib thickness adjusting mechanism of the hand pencil sharpener, the front side surface of the rear cover is convexly provided with an annular part concentrically arranged with the rear cover, each positioning groove and each guiding slope surface are positioned on the front side surface of the annular part, the front side of the adjusting head is provided with an annular convex part which is positioned on the inner side of the annular part and forms clearance fit with the annular convex part, and the convex part is positioned on the outer periphery side of the annular convex part.

In the nib thickness adjusting mechanism of the hand pencil sharpener, the front side face of the annular part is convexly provided with two limiting sheets, each positioning groove is positioned between the two limiting sheets, the positioning groove which is positioned between the guiding Kong Zuiyuan and one of the limiting sheets is adjacent to the positioning groove, and the positioning groove which is positioned closest to the guiding hole is adjacent to the other limiting sheet.

The positioning groove of the distance guide Kong Zuiyuan is adjacent to one of the limiting sheets, which means that the adjusting head can only rotate in the direction of thinning the sharpened pencil point in the state that the lug is clamped into the positioning groove; similarly, the positioning groove closest to the guide hole is adjacent to the other stopper, meaning that the adjustment head can only be rotated in a direction to thicken the sharpened pencil point in a state where the lug is caught in the positioning groove. Such an arrangement makes it difficult for the user to malfunction, such as to adjust directly to the thinnest state of the shaved nib in the thickest state of the shaved nib.

In the nib thickness adjusting mechanism of the hand pencil sharpener, the rear cover is a plastic piece, the front side edge of the rear cover is fixedly connected with a plurality of connecting pieces which are arranged forwards along the circumferential direction, the front end parts of the connecting pieces are respectively provided with a buckling part, the rear cover is correspondingly provided with a plurality of buckling grooves in the notch, the buckling parts are buckled in the buckling grooves, the annular parts are fixedly connected with the inner side surfaces of the connecting pieces, and the two limiting pieces are fixedly connected with the inner side surfaces of the two connecting pieces.

The rear cover is connected with the handle body through the matching of the buckling part and the buckling groove. The annular part is fixedly connected with the inner side surface of each connecting sheet, and the two limiting sheets are fixedly connected with the inner side surfaces of the two connecting sheets, so that the overall structural strength of the rear cover is better, and the rear cover is more durable in long-term use.

In the nib thickness adjusting mechanism of the hand pencil sharpener, the rear side surface of the rear cover is provided with the marking part which is in an arc shape and is arranged concentrically with the rear cover, the width of the marking part is gradually increased along the arc, the increasing direction of the width of the marking part along the arc is the same as the increasing direction of the distance between each part on the guiding slope and the guiding hole, and the rear end part of the operating part is provided with the indicating part matched with the marking part.

Through the arrangement, a user can intuitively grasp the adjustment direction of the thickness of the pen point, and misoperation is avoided.

In the nib thickness adjusting mechanism of the hand pencil sharpener, the front end of the knife rest is provided with a pencil placing hole, the knife rest is provided with a push block in a sliding manner along the front-back direction, the push block is provided with a plate-shaped part positioned between the hole of the rear end of the pencil placing hole and the front end part of the push rod, and the plate-shaped part is propped against the front end part of the push rod.

The plate-shaped part can form more effective contact with the pen point of the pencil, and is more stable when the broken core is pushed out.

Compared with the prior art, the nib thickness adjusting mechanism of the hand pencil sharpener is provided with lugs at the side part of the front end of the adjusting head and is matched with the guide slope which is arranged in the installation cavity of the crank in an arc shape and surrounds the center line of the guide hole to specifically realize the nib thickness adjusting function, so that the rear end of the pushing rod is not required to be provided with an expanding section with the size larger than that of the guide hole, and then the front end of the adjusting head is arranged in the guide hole in a combined way so that the adjusting head can extend into the guide hole when moving forwards, so that the distance for pushing broken cores is increased, and the nib thickness adjusting mechanism of the hand pencil sharpener has nib thickness adjusting function and broken core pushing function to improve applicability and has ideal broken core pushing effect.

Drawings

Fig. 1 is a schematic view of a nib thickness adjusting mechanism of the hand pencil sharpener.

Fig. 2 is another angle schematic view of the nib thickness adjusting mechanism of the hand pencil sharpener.

Fig. 3 is a sectional view of a nib thickness adjusting mechanism of the hand pencil sharpener.

Fig. 4 is a schematic view of a tool holder.

Fig. 5 is an exploded view of the crank.

Fig. 6 is a schematic view of the fit between the adjustment head and the rear cover.

Fig. 7 is a schematic view of another angular fit between the adjustment head and the rear cover.

Fig. 8 is a schematic view of the rear cover.

Fig. 9 is a schematic view of an adjustment head.

In the figure, 1, a knife rest; 1a, a pen placing hole; 1b, a guide hole; 1c, a rotation preventing hole; 2. an inner gear ring; 3. a crank; 3a, a mounting cavity; 3b, guiding the slope; 3b1, positioning grooves; 3c, a handle body; 3c1, notches; 3c2, a buckling groove; 3d, a rear cover; 3d1, a ring portion; 3d11, limiting sheets; 3d2, connecting pieces; 3d21, a buckling part; 3d3, a marking part; 4. a hob; 5. a gear; 6. a push rod; 6a, a guide head; 6b, a rod part; 7. adjusting the head; 7a, lugs; 7b, an abutting part; 7c, an operation part; 7c1, an instruction unit; 7d, annular convex part; 8. a spring; 9. a pushing block; 9a, plate-like portion.

Detailed Description

The following are specific embodiments of the present utility model and the technical solutions of the present utility model will be further described with reference to the accompanying drawings, but the present utility model is not limited to these embodiments.

As shown in fig. 1 and 3, the pen point thickness adjusting mechanism of the hand pencil sharpener comprises a frame (not shown in the drawings), an inner gear ring 2, a cutter rest 1 and a crank 3, wherein the rear end of the cutter rest 1 penetrates through the inner gear ring 2 and is fixedly connected with the crank 3, a through pen placing hole 1a is formed in the front end of the cutter rest 1 along the front-back direction, a notch is formed in the side part of the pen placing hole 1a, a hob 4 is connected to the cutter rest 1 and is positioned in the notch, and a gear 5 meshed with the inner side of the inner gear ring 2 is fixedly connected to the rear end of the hob 4.

As shown in fig. 2 to 9, the crank 3 has a mounting cavity 3a therein, and the rear end of the holder 1 has a guide hole 1b communicating with the mounting cavity 3 a. The pen point thickness adjusting mechanism comprises a push rod 6 penetrating through a guide hole 1b and an adjusting head 7, wherein the front end of the adjusting head 7 is positioned in an installation cavity 3a, the rear end of the adjusting head extends out of a crank 3, the adjusting head 7 is in sliding connection with the crank 3 in the front-back direction, and the adjusting head 7 can rotate relative to the crank 3. The crank 3 is provided with a guide slope 3b which is arc-shaped and is arranged around the central line of the guide hole 1b in the installation cavity 3a, a plurality of positioning grooves 3b1 are arranged on the guide slope 3b, and the front end of the adjusting head 7 is provided with a lug 7a which is provided with a side part and can move along the guide slope 3b and can be clamped into any one of the positioning grooves 3b1 when the adjusting head 7 rotates. The rear end of the push rod 6 is provided with a guide head 6a in clearance fit with the guide hole 1b, the rear end of the tool rest 1 is internally provided with an anti-rotation hole 1c which is arranged along the front-rear direction, the anti-rotation hole 1c is a non-circular hole, the rear end orifice of the anti-rotation hole 1c is communicated with the front end orifice of the guide hole 1b, the push rod 6 is further provided with a rod part 6b with a cross section matched with the anti-rotation hole 1c, the cross section of the rod part 6b is smaller than that of the guide head 6a, and the front end of the rod part 6b penetrates out of the anti-rotation hole 1 c. The guide hole 1b is internally provided with a spring 8, the spring 8 is sleeved outside the rod part 6b, two ends of the spring 8 respectively lean against the inner wall of the front end of the guide hole 1b and the guide head 6a, the guide head 6a is partially positioned in the mounting cavity 3a and leans against the front end part of the adjusting head 7, and the front end part of the adjusting head 7 can extend into the guide hole 1b when the adjusting head 7 moves forwards. Specifically, the adjustment head 7 is columnar and is disposed concentrically with the guide hole 1b, and the adjustment head 7 has an abutment portion 7b at a center position of a front end portion thereof, the abutment portion 7b having an outer dimension smaller than the guide hole 1b. The rear end of the adjustment head 7 has an external hexagonal operation portion 7c. The cutter holder 1 is provided with a push block 9 slidably in the front-rear direction, the push block 9 having a plate-like portion 9a located between the rear end aperture of the pen hole 1a and the lever portion 6b, the plate-like portion 9a abutting against the front end of the lever portion 6 b.

As shown in fig. 2 to 9, the crank 3 includes a handle body 3c having a recess 3c1 at a rear side thereof and a rear cover 3d detachably attached to the recess 3c1, an inner cavity is formed between the handle body 3c and the rear cover 3d, the rear cover 3d has a through hole through which the operation portion 7c protrudes, and a guide slope 3b is provided at a front side of the rear cover 3 d. Further, the front side surface of the rear cover 3d is convexly provided with an annular portion 3d1 concentrically arranged therewith, each positioning groove 3b1 and each guiding slope 3b are located on the front side surface of the annular portion 3d1, the front side of the adjustment head 7 is provided with an annular protruding portion 7d located inside the annular portion 3d1 and forming clearance fit therewith, and the lug 7a is located on the outer peripheral side of the annular protruding portion 7 d. The front side of the annular part 3d1 is convexly provided with two limiting sheets 3d11, each positioning groove 3b1 is positioned between the two limiting sheets 3d11, the positioning groove 3b1 farthest from the guide hole 1b is adjacent to one of the limiting sheets 3d11, and the positioning groove 3b1 nearest to the guide hole 1b is adjacent to the other limiting sheet 3d 11. The number of the guide slope surfaces 3b is two, the two guide slope surfaces 3b and the two limiting plates 3d11 are arranged at intervals, a positioning groove 3b1 on one guide slope surface 3b, which is farthest from the guide hole 1b, and a positioning groove 3b1 on the other guide slope surface 3b, which is closest to the guide hole 1b, are positioned on two sides of the same limiting plate 3d11, and when the number of lugs 7a is correspondingly two, the number of the positioning grooves 3b1 on each guide slope surface 3b is 3.

As shown in fig. 2 and 4, in the present embodiment, the front side edge of the rear cover 3d is fixedly connected with a plurality of connecting pieces 3d2 disposed forward in the circumferential direction, the front end portion of each connecting piece 3d2 has a fastening portion 3d21, the rear cover 3d has a plurality of fastening grooves 3c2 in the recess 3c 1 correspondingly, and each fastening portion 3d21 is fastened in the fastening groove 3c 2. The annular part 3d1 is fixedly connected with the inner side surface of each connecting sheet 3d2, and the two limiting sheets 3d11 are fixedly connected with the inner side surfaces of the two connecting sheets 3d 2. The rear side surface of the rear cover 3d is provided with a marking part 3d3 which is in an arc shape and is concentrically arranged with the marking part, the width of the marking part 3d3 is gradually increased along the arc, the width of the marking part 3d3 is the same as the increasing direction of the distance between each part on the guide slope surface 3b and the guide hole 1b along the arc, and the rear end part of the operation part 7c is provided with an indication part 7c1 matched with the marking part 3d 3.

The specific embodiments described herein are offered by way of example only to illustrate the spirit of the utility model. Those skilled in the art may make various modifications or additions to the described embodiments or substitutions thereof without departing from the spirit of the utility model or exceeding the scope of the utility model as defined in the accompanying claims.

Claims (9)

1. The pen point thickness regulating mechanism of the hand pencil sharpener comprises a knife rest (1) and a crank (3) fixedly connected to the rear end of the knife rest (1), wherein a mounting cavity (3 a) is arranged in the crank (3), a guide hole (1 b) communicated with the mounting cavity (3 a) is arranged at the rear end of the knife rest (1), the pen point thickness regulating mechanism comprises a push rod (6) penetrating through the guide hole (1 b) and a regulating head (7) with the front end positioned in the mounting cavity (3 a) and the rear end extending out of the crank (3), the regulating head (7) and the crank (3) are in sliding connection along the front and rear direction, the regulating head (7) can rotate relative to the crank (3), a spring (8) with elasticity acting on the push rod (6) towards the rear is arranged in the guide hole (1 b), the rear end of the push rod is provided with a guide head (6 a) in clearance fit with the guide hole (1 b), the crank (3) is characterized in that the mounting cavity (3 a) is provided with a slope surface and a plurality of guide heads (7) which are arranged around the guide hole (1 b) and can be positioned in the slope surface (3 b) and can move along the guide groove (7 b) of the regulating head (3 b) when the slope surface (3 b) is positioned in the slope surface (3), the guide head (6 a) is abutted against the front end part of the adjusting head (7), and the front end of the adjusting head (7) can extend into the guide hole (1 b) when the adjusting head (7) moves forwards.

2. The nib thickness adjusting mechanism of a hand pencil sharpener according to claim 1, wherein the adjusting head (7) is columnar and is arranged concentrically with the guide hole (1 b), an abutting portion (7 b) is provided at a center position of a front end portion of the adjusting head (7), and an outer dimension of the abutting portion (7 b) is smaller than that of the guide hole (1 b).

3. The nib thickness adjusting mechanism of a hand pencil sharpener according to claim 2, wherein the rear end of the adjusting head (7) has an external hexagonal operating portion (7 c).

4. A nib thickness adjusting mechanism of a hand pencil sharpener according to claim 3, characterized in that the crank (3) comprises a handle body (3 c) with a notch (3 c 1) at the rear side and a rear cover (3 d) detachably connected in the notch (3 c 1), the cavity is formed between the handle body (3 c) and the rear cover (3 d), the rear cover (3 d) is provided with a through hole for the operation part (7 c) to extend, and the guiding slope (3 b) is arranged at the front side of the rear cover (3 d).

5. The nib thickness adjusting mechanism of a hand pencil sharpener according to claim 4, wherein the front side of the rear cover (3 d) is provided with a ring-shaped part (3 d 1) protruding and arranged concentrically with the front side, each positioning groove (3 b 1) and each guiding slope (3 b) are positioned on the front side of the ring-shaped part (3 d 1), the front side of the adjusting head (7) is provided with a ring-shaped protruding part (7 d) positioned on the inner side of the ring-shaped part (3 d 1) and forming clearance fit with the ring-shaped protruding part (7 d), and the lug (7 a) is positioned on the outer circumference side of the ring-shaped protruding part (7 d).

6. The nib thickness adjusting mechanism of a hand pencil sharpener according to claim 5, wherein two limiting plates (3 d 11) are arranged on the front side surface of the annular portion (3 d 1) in a protruding mode, each positioning groove (3 b 1) is located between the two limiting plates (3 d 11), the positioning groove (3 b 1) farthest from the guiding hole (1 b) is adjacent to one of the limiting plates (3 d 11), and the positioning groove (3 b 1) nearest to the guiding hole (1 b) is adjacent to the other limiting plate (3 d 11).

7. The nib thickness adjusting mechanism of a hand pencil sharpener according to claim 6, wherein the rear cover (3 d) is a plastic piece, the front side edge of the rear cover (3 d) is fixedly connected with a plurality of connecting pieces (3 d 2) which are arranged forward along the circumferential direction, the front end parts of the connecting pieces (3 d 2) are respectively provided with a buckling part (3 d 21), the rear cover (3 d) is correspondingly provided with a plurality of buckling grooves (3 c 2) in the notch (3 c 1), each buckling part (3 d 21) is buckled in the buckling groove (3 c 2), the annular part (3 d 1) is fixedly connected with the inner side surface of each connecting piece (3 d 2), and the two limiting pieces (3 d 11) are fixedly connected with the inner side surfaces of two connecting pieces (3 d 2).

8. The nib thickness adjusting mechanism of a hand pencil sharpener according to claim 4, 5, 6 or 7, wherein the rear side surface of the rear cover (3 d) is provided with a marking part (3 d 3) which is circular arc-shaped and is arranged concentrically with the rear cover, the width of the marking part (3 d 3) is gradually increased along the circular arc, the width of the marking part (3 d 3) is the same as the increasing direction of the distance from each part on the guide slope (3 b) to the guide hole (1 b) along the increasing direction of the circular arc, and the rear end part of the operating part (7 c) is provided with an indicating part (7 c 1) matched with the marking part (3 d 3).

9. The nib thickness adjusting mechanism of a hand pencil sharpener according to claim 1, wherein the front end of the cutter holder (1) is provided with a pencil hole (1 a), the cutter holder (1) is provided with a push block (9) in a sliding manner along the front-rear direction, the push block (9) is provided with a plate-shaped portion (9 a) located between the rear end hole of the pencil hole (1 a) and the front end portion of the push rod (6), and the plate-shaped portion (9 a) abuts against the front end portion of the push rod (6).