JP2010005764A - Screw fastening machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a user-friendly screw fastening machine capable of accurately positioning a screw in a hole of a joint metal fitting before starting fastening of the screw. <P>SOLUTION: The screw fastening machine 1 is provided with a screw fastening tool 2, a guide section 6 covering a screwdriver bit 10, and a sliding section 35 movable in the axial direction of the screwdriver bit 10 relative to the guide section 6, a magazine section 40 which stores a coupling band 45 holding a plurality of screws 46 being fixed to the sliding section 35. A sleeve 21 slidable in its axial direction is provided on the outside of the screwdriver bit 10 and between the screwdriver bit 10 and the guide section 6, and is rotated by interlocking with the screwdriver bit 10. A magnet 30 disposed on the tip end of the sleeve 21 attracts a head of the screw 46 held by the coupling band 45 and rotates the screw 46 by transmitting the rotating force of the screwdriver bit 10 via the sleeve 21. On this occasion, the screw 46 is advanced and is stopped at a projected position from the sliding section 35 by an action made between a thread of the screw 46 and a holding section of the coupling band 45. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a screw tightening machine having a screw feeding mechanism that feeds a screw from a magazine containing a plurality of screws held by a connecting band to a tip of a driver bit at regular intervals. The present invention relates to a screw tightening machine capable of facilitating tightening alignment by causing a screw to protrude from the tip of a main body.

  Patent Document 1 discloses a screw tightening machine having a screw feed mechanism that sets a plurality of loose screws, feeds them one by one on the driver bit axis, and tightens the screws by pressing the driver tool in the direction of the tightening material. ing. In Patent Document 1, a screw feeding mechanism for feeding screws one pitch at a time is provided in the magazine, and the magazine is mounted on the sliding member so that the screw guide groove is positioned at right angles to the longitudinal axis of the sliding member. The screw feeding mechanism is interlocked with the operating mechanism. Then, the screw is fed one pitch by one reciprocating motion of the sliding member, the screw is tightened by a driver bit, and this operation is continuously repeated to tighten the screw.

JP-A-6-339870

  In the structure shown in Patent Document 1, the screw before tightening is held inside the screw tightening machine, and it is difficult to position the tip of the screw during screw tightening, and it is difficult to tighten the screw accurately at a predetermined position. there were. In particular, when fixing a joint fitting used for residential construction to a building material, it has been required that the hole of the joint fitting can be screwed to an accurate position because the gap with the screw is small.

  An object of the present invention is to provide an easy-to-use screw tightening machine that can accurately position a screw in a hole such as a joint fitting before starting screw tightening.

  Another object of the present invention is to provide a screw tightening machine that can project the tip of a screw from the screw tightening machine before tightening with a simple configuration.

  Still another object of the present invention is to provide a screw tightening machine capable of controlling two types of operations, that is, an operation of advancing and projecting a screw and a screw tightening operation by simply pulling a trigger switch of the screw tightening tool. is there.

  Of the inventions disclosed in the present application, typical features will be described as follows.

  According to one aspect of the present invention, a screw tightening tool that rotates a driver bit, a guide portion that is attached to the screw tightening tool and covers the driver bit, and is movable relative to the guide portion in the axial direction of the driver bit. A screw fastening machine in which a sliding part is provided, a sliding part is provided with a connecting band for holding a plurality of screws, and a magazine part for sequentially transferring the screws held in the connecting band onto the axis of the driver bit , A sleeve that is rotated by the driver bit and is slidable in the axial direction is provided between the outer periphery of the driver bit and the guide portion, a magnet is attached to the tip of the sleeve, and the screw held in the coupling band is magnetized. And the rotational force of the driver bit is transmitted to the screw through the sleeve, and is caused by the action of the screw thread of the rotated screw and the holding part of the connecting band. By advancing the screw, and so as to protrude the screw from the sliding portion. The sleeve is preferably cylindrical, and the inner peripheral side of the sleeve corresponds to the outer diameter of the driver bit, and is preferably polygonal so that when the driver bit rotates, the sleeve also rotates in conjunction with it.

  According to another characteristic of the invention, the connecting band has an upper lip and a lower lip for holding the screw, the rotation of the screw when the sleeve is rotated, and the action of the screw thread and the lower lip. To advance the screw and stop the screw advancement when the screw head reaches the lower lip. A gripping means for holding the sliding portion and the screw tip projecting from the sliding portion is provided, and the gripping means has two members separated in the axial direction and the vertical direction. After holding the screw with the tip of the screw protruding from the sliding part, the screw tightening tool is operated and pressed in the screw direction, so that the sliding part moves in the direction approaching the screw tightening tool and the screwdriver bit The tip engages with the screw, and screw tightening is performed.

  According to still another feature of the present invention, the sleeve is urged rearward by a spring means disposed between the sliding portion, and the sliding portion is provided by a spring means disposed between the guide portion. It is urged forward. The magazine portion has transfer means for moving the connecting band so as to approach the axis of the driver bit. The transfer means is, for example, a holder biased by a ribbon spring. The sliding portion may be formed with an opening for discharging the connecting band portion holding the tightened screw to the outside.

  According to the invention of claim 1, by providing a sleeve that is rotated by a driver bit and is slidable in the axial direction, a magnet is attached to the tip of the sleeve, a screw is rotated through the sleeve, and the screw is advanced, Since the screw protrudes from the sliding portion, the operator can pull the trigger without pressing the screw tightening tool to protrude the screw from the tip of the sliding portion before tightening the screw. Therefore, since the screw is protruded from the tip, a special operation is not required, and a screw tightening machine that makes positioning of the screw extremely easy can be realized.

  According to the invention of claim 2, since the sleeve is cylindrical and the inner peripheral side of the sleeve is a polygonal shape corresponding to the outer diameter of the driver bit, the sleeve rotates in synchronization with the driver bit and is axially A movable configuration can be realized with a simple shape.

  According to the invention of claim 3, the connecting band has an upper lip and a lower lip for holding the screw, the screw advances by the action of the screw thread and the lower lip, and the screw head is lowered. Since the screw stops moving when it reaches the side lip, the screw can be advanced using the lip of the connection band, and the screw will continue to rotate more than necessary by continuing to rotate the screw tightening tool. Therefore, a user-friendly screw tightening tool can be realized.

  According to the invention of claim 4, the sliding part is provided with the gripping means for holding the screw with the tip of the screw protruding from the sliding part, and the gripping means is two members separated in the axial direction and the vertical direction. Therefore, the screw can be effectively held by the gripping means at the time of tightening, and the screw head easily passes between the two separated members immediately before the tightening of the screw, so that the screw can be tightened smoothly. be able to.

  According to the invention of claim 5, since the tip of the driver bit is engaged with the screw by operating and advancing the screw tightening tool in a state in which the screw protrudes, the screw tightening is performed. In addition, the screw tightening operation can be started simply by pressing the screw tightening tool in the direction of the screw.

  According to the sixth aspect of the present invention, the sleeve is urged rearward in the axial direction of the driver bit by the spring means disposed between the sliding portions, and the sliding portions are disposed between the guide portions. Since the screw means is urged forward in the axial direction by the spring means, the sleeve and the sliding portion can automatically return to their original positions when the screw advancement or screw tightening is completed.

  According to the seventh aspect of the present invention, since the magazine section has the transfer means for moving the connecting band so as to approach the axis of the driver bit, the next screw is transferred by the transfer means when the screw tightening is completed. Therefore, the screw tightening operation can be performed easily and continuously.

  According to the invention of claim 8, since the sliding portion has the opening for discharging the connecting band portion holding the tightened screw to the outside, the used portion of the connecting band is the next screw. The screw tightening operation can be performed continuously without hindering the tightening operation.

  The above and other objects and novel features of the present invention will become apparent from the following description and drawings.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiments, and the repetitive description thereof will be omitted. In the present specification, unless otherwise specified, the direction indicated by the arrow in FIG.

  FIG. 1 is a view showing the entire screw tightening machine 1, and a longitudinal sectional side view is partially shown. The screw tightening machine 1 includes a screw tightening tool 2 such as an impact driver or an electric screwdriver, a guide portion 6 attached to the front side near the rotation axis of the screw tightening tool 2, and relative to the guide portion in the axial direction of the driver bit. And a magazine portion 40 fixed to the sliding portion 35. A spindle case 15 is provided at the lower portion of the screw tightening tool 2, and the spindle 3 is disposed at the center thereof. A driver bit 10 is attached to the spindle 3. The guide unit 6 includes a holder 4 that is fixed to the spindle case 15 with bolts 12 and a guide pipe 7 that is rotatably fixed to the holder 4 with screws 11.

  The sliding portion 35 includes a sliding body 20 disposed inside the guide pipe 7 and a sliding body guide 25 fixed to the sliding body 20. The sliding portion 35 is held by a groove provided in the guide pipe 7 so that it cannot rotate with respect to the guide pipe 7 and can slide back and forth with respect to the guide pipe 7. A cylindrical space is provided above the sliding body 20, and a sleeve 21 that is slidable in the front-rear direction with respect to the driver bit 10 and is mounted so as not to rotate relative to the driver bit 10 is provided in the space. . The sleeve 21 has a substantially cylindrical shape with a circular outer periphery and a hexagonal inner periphery, and is provided with a flange 21a extending radially outward toward the rear in the front-rear direction. The front surface of the flange 21a and the sliding body 20 are provided. It is fixed so as to be movable in the axial direction via a cone spring 23 mounted between the through hole and the rear surface side periphery. Since the rear surface of the flange 21a comes into contact with the front surface of the retaining ring 26 attached to the inner circumferential recess of the cylindrical space of the sliding body 20, the sliding distance of the sleeve 21 is restricted. The cone spring 23 is a compression spring and urges the flange 21 to move rearward in the axial direction.

  The sliding body 20 is urged by a spring 9 disposed between the sliding body 20 and a spring seat 8 provided to face the spindle 3. The spring 9 is a compression spring, and the urging direction is a direction in which the sliding body 20 moves forward with respect to the screw tightening tool 2. The moving distance of the sliding body 20 is limited by a stopper such as a screw provided on the guide pipe 7.

  The magazine portion 40 is positioned by a pin 42 between the magazine case holder 53 and the sliding body guide 25 and is fixed by a bolt 43. The magazine section 40 includes a ribbon spring 41, a magazine case 50, a shaft 52, and a ribbon spring holder 44. One end of the ribbon spring 41 is fixed to the magazine case presser 53 through the above-described pin 42 passing through a hole provided there. One side where the ribbon spring 41 is wound is housed on the left side of the ribbon spring holder 44, and the ribbon spring holder 44 is urged toward the driver bit 10 side (right side in the figure) by the ribbon spring 41. The ribbon spring holder 44 is slidably disposed in the magazine case 50 and urges the connecting band 45 holding the screws 46 at equal intervals to the right side. In this way, the leading screw 46 is screwed into the hole of the joint fitting 60 held on the material to be tightened 61 such as wood.

  In the magazine portion 40 attached to the sliding portion 35, the guide pipe 7 is rotatably held with respect to the holder 4 fixed to the spindle case 15. For this reason, when the magazine part 40 interferes with woods (materials to be tightened) such as beams depending on the work location, the magazine part 40 can be rotated to avoid interference.

  FIG. 2 is a longitudinal sectional view of the guide portion 6 and the sliding portion 35 as seen from another angle. This figure is a cross-sectional view of a plane rotated 90 degrees with respect to FIG. 1 when viewed in the axial direction of the driver bit 10. When the cylindrical magnet 30 is fixed to the lower end of the sleeve 21 and the head of the screw 46 is close, the sleeve 21 and the head of the iron screw 46 are brought into close contact with each other by a strong magnetic force and a magnetic path appropriately taken into consideration. Washers 27 a and 27 b are disposed above and below the retaining ring 26 to facilitate the rotational movement of the sleeve 21. The screw connection band 45 is made of a soft resin having a U-shaped cross section, and one side of the U-shape moves in the longitudinal direction of the magazine portion 40 via the connection band guide groove 112. Thus, since the connection band 45 is guided by the connection band guide groove 112, when the screw 46 rotates and advances, the connection band 45 is prevented from being influenced by the force and deformed.

  When the screw 46 moves forward and jumps out of the sliding body 20 and stops, the screw retainer 121 prevents the tip from shaking, and the screw retainer 121 is processed obliquely so that the head of the screw 46 can easily pass. A guide surface 121a is formed. Further, the sliding body 20 has gripping means, that is, a screw presser 121 and a leaf spring 115 (a portion indicated by a thick line attached to the outside of the sliding body 20 in the figure) so that the head of the screw 46 can easily pass. Provided. The screw retainer 121 is fixed to the leaf spring 115 with a screw 120, and the leaf spring 115 is fixed to the sliding body 20 with the screw 100. The screw retainer 121 can be moved by the leaf spring 115 by a small distance in a direction away from the axial direction indicated by the arrow 28 in a direction perpendicular thereto.

  FIG. 3 is a partial front view of the sliding body 20 as viewed from the AA portion in FIG. The screw retainers 121 are provided as a pair (separated into left and right in the drawing), and a screw passage 122 is formed therebetween. When the screw thread portion of the screw 46 passes through the screw passage 122, the screw 46 is firmly held by the screw thread formed on the inner peripheral side of the screw retainer 121, but the head of the screw 46 b passes through the screw passage 122. In this case, the screw retainer 121 moves in the left-right direction in the drawing to allow the screw head to pass therethrough. Two notches extending in the axial direction rearward from the tip end of the guide pipe 7 are provided at two circumferential locations (upper and lower in the figure) of the guide pipe 7, and the upper notch 7 a discharges the connecting band 45. The lower notch (not labeled in the drawing) functions to ensure a sliding range of the sliding portion 35 to which the magazine portion 40 is attached.

  4 is a cross-sectional view taken along the line BB in FIG. In FIG. 4, the connecting band 45 holding the screw 46 is accommodated in the magazine case 50 so as to pass through the square hole 20 a formed in the sliding body 20 by being urged by the ribbon spring holder 44 as a transfer means. I can move. The connection band 45 is provided with a concave cut groove 45 c for holding the screw 46. In addition, a slit 45d is provided between adjacent screws so that the connecting band can be deformed so that the screws 46 can be easily detached. A case cap 200 is fixed to the left end of the magazine case 50 by a bolt 160 and a nut 161.

  FIG. 5 is a perspective view showing a state in which the screw 46 is attached to the connecting body 45. A plurality of the connecting screws 7 are inserted and locked in the concave cut grooves 45c of the upper lip 45a and the lower lip 45b which are largely separated in the screw axis direction of the connecting band 45, and a plurality of the connecting screws 7 are held at equal intervals. The present embodiment is characterized in that the upper lip 45a and the lower lip 45b of the connecting band 45 hold the screw 46 at two locations that are largely separated in the axial direction of the screw 45. A slit 45d is provided between the lips with the adjacent recessed cut groove.

  FIG. 6 is a cross-sectional view of the CC section in FIG. 1 and a view of the sliding body guide 25 direction from the CC section. In FIG. 6, a case rib 50 b is provided in the longitudinal direction of the magazine case 50. Further, a case folding 50c is provided on the front side (lower part in the figure), and the connection band 45 is prevented from falling off.

  7 is a cross-sectional view of the DD portion of FIG. 1 and a view of the sliding body guide 25 direction from the DD portion. In FIG. 7, the ribbon spring 41 that has entered the ribbon spring holder 44 is covered with a cap 125 to prevent the ribbon spring 41 from falling off. The shaft 52 disposed through the magazine case 50 is movably held in the groove of the case rib 50b.

Next, the operation | movement at the time of the screw fastening in this embodiment is demonstrated using FIG. 1 and FIGS.
In FIG. 1, when the trigger switch of the screw tightening tool 2 is pulled to turn on a motor (not shown), the driver bit 10 rotates and the sleeve 21 rotates accordingly. A magnet 30 is fixed to the tip of the sleeve 21 and is close to the head of the screw 46. Therefore, the magnet 30 is attracted to the screw head by a magnetic force, and is fixed to the screw head against the force of the cone spring. As a result, the screw 46 also rotates in synchronization with the sleeve 21. At this time, since the lower lip 45b of the connecting band 45 has a function of a female screw, the screw 46 moves forward. Since the magnet 30 and the screw 46 are integrated by magnetic force, the sleeve 21 is pulled by the advancement of the screw 46 and moves by compressing the cone spring 23. The head of the screw 46 immediately moves away from the upper lip 45a, but continues to advance by the function of the female screw of the lower lip 45b. Even after the end of the screw thread of the screw 46 passes through the lower lip 46b, the screw groove formed on the inner peripheral side of the screw retainer 121 and the screw thread of the screw 46 continue to advance, and the flange 21a of the sleeve 21 continues. Moves until it hits the bottom of the hole provided in the sliding body 20. FIG. 8 shows this state.

  This state can be maintained by returning the trigger 5 to stop the idling of the driver bit 10. As a result, as shown in FIG. 8, the tip of the screw 46 protrudes from the sliding body 20. Since the screw presser 121 is provided at the tip of the sliding body 20, the screw 46 does not shake in the vertical direction with respect to the shaft and is firmly fixed. In this state, the tip of the screw 46 can be guided to the center of the hole of the joint fitting 60. At this time, since the lower lip 45b of the connection band 45 is held by the connection band guide groove 112 as shown in FIG. 2, it is possible to prevent one side of the connection band 45 from being deformed upward.

  In FIG. 9, the operator pulls the trigger 5 (FIG. 1) again in a state where the tip of the screw 46 is positioned at the center of the hole of the joint fitting 60, and moves the screw tightening tool 2 in the direction of the material 61 to be tightened, that is, an arrow. Push in direction 29. Then, while the spring 9 is compressed, the sliding member 20 moves so as to approach the screw tightening tool 2, the tip of the driver bit 10 and the groove of the head of the screw 46 are engaged, and the screw starts rotating by the driver bit 10, and the material to be tightened Tightening of the screw 46 to 61 is started.

  In FIG. 10, when the screw tightening tool 2 is further pressed against the material 61 to be tightened, the screw 46 enters the material 61 to be tightened. At this time, since the sleeve 21 cannot advance further, the magnet 30 at the tip of the sleeve 21 and the head of the screw 46 are separated. As a result, the magnet 30 loses its attractive force to the screw 46 and the sleeve 21 is returned upward by the cone spring 23. Further, by the action of the guide surface 121a (FIG. 2), the screw spring 121 causes the leaf spring 115 to bend in the direction of the arrow to widen the screw passage 122 and facilitate the passage of the screw 46 through the screw head.

  In FIG. 11, when the screwdriver tool 10 is rotated and the screw tightening tool 2 is further pressed, the screw 46 further enters the material 61 to be tightened, and the head of the screw comes into contact with the joint fitting 60 to complete the tightening. The end state can be confirmed visually by the notch 7a serving as a window. When the screw tightening is finished and the operator releases the pressing of the screw tightening tool 2 against the material to be tightened, the sliding portion 35 returns to the initial position by the action of the spring 9.

  In FIG. 12, when the pressing force of the screw tightening tool 2 is released after the screw tightening is completed, the sliding body 20 returns to the position shown in FIG. At this time, since the driver bit 10 has come out of the connection band 45, the connection band 45 urged by the ribbon spring 41 moves to the right by one pitch, and the head of the next screw 46 moves to the sliding body 20. Move until it touches the inner wall. At that position, the axis of the driver bit 10 and the axis of the screw 46 coincide with each other, and preparation for the next screw tightening is completed. The empty screw portion of the connecting band 45 moves to the right after passing through the square hole 20a (FIG. 4) provided in the sliding body 20. The part where the screw 46 of the connecting band 45 is displaced from the screw mounting grooves 45 a and 45 b is protruded from the sliding body 20.

  According to the present invention, since the screw can be accurately positioned in the hole for fastening the joint fitting or the like before the start of the screw tightening, a user-friendly screw tightening machine can be provided. Further, it is possible to feed the connecting screws one by one with a simple configuration, and to project the tip of the screw from the screw tightening machine before tightening. Furthermore, the operation of projecting the screw can be executed by a one-touch operation of pulling the trigger switch, so that the operability is very good.

  The invention made by the present inventor has been specifically described based on the embodiment of the screw tightening machine. However, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention. Is possible. For example, in the above-described embodiment, an example in which an electric impact driver is used as a screw tightening tool has been described. However, the present invention is not limited to an electric tool, and an air tool powered by air, an engine tool, and the like It is also possible to use.

  Furthermore, in the above-described embodiment, the example in which the driver bit 10 having a square tip and the screw corresponding thereto is used has been described, but the shape of the driver bit and the shape of the fastening member are not limited to these combinations, Needless to say, other shapes of driver bits, screws, bolts and the like can be used.

  In this embodiment, the connecting screw 45 uses a resin-made connecting band having a U-shaped cross section. However, the shape of the connecting band is not limited to the U-shaped but a connecting band having an arbitrary shape. Can be used. Further, by changing the screw holding position by the upper lip 45a, not only the lower lip 45b but also the upper lip 45a can have the function of a female screw.

It is a side view which shows the whole screw fastening machine which concerns on embodiment of this invention, and shows a longitudinal cross-sectional view in part. It is the longitudinal cross-sectional view which looked at the guide part 6 and the sliding part 35 of the screw fastening machine shown in FIG. 1 from another angle. It is the partial front view which looked at the screw fastening machine shown in FIG. 1 from the front-end | tip. It is sectional drawing of the BB part of FIG. It is a perspective view which shows the attachment state of the screw 46 to the connection body 45 of FIG. It is the sectional view of CC section of Drawing 1, and the figure which looked at slide body guide 25 direction from CC section. It is the figure which looked at the slide body guide 25 direction from sectional drawing of DD part of FIG. 1, and DD part. It is side surface sectional drawing of the front-end | tip part which shows the state which the screw protruded from the screw fastening machine which concerns on embodiment of this invention. It is side surface sectional drawing of the front-end | tip part which shows the state which starts tightening a screw with the screw tightening machine which concerns on embodiment of this invention. It is front sectional drawing of the front-end | tip part which shows the state in which the screw is tightening with the screw tightening machine which concerns on embodiment of this invention. It is side surface sectional drawing of the front-end | tip part which shows the state which complete | finished screwing with the screwing machine which concerns on embodiment of this invention. It is side surface sectional drawing of the front-end | tip part which shows the state which complete | finished screw tightening with the screw tightening machine which concerns on embodiment of this invention, the sliding part returned to the initial position, and the connection band was sent 1 pitch.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Screw tightening machine 2 Screw tightening tool 3 Spindle 4 Holder 5 Trigger 6 Guide part 7 Guide pipe 7a Notch 8 Spring seat
9 Spring 10 Driver bit 11 Screw 12 Bolt 15 Spindle case 20 Slider 20a Square hole 21 Sleeve 21a Flange
23 Cone Spring 25 Slider Guide 26 Retaining Ring
27a, 27b Washer 30 Magnet 35 Sliding part 40 Magazine part 41 Ribbon spring 42 Pin 43 Bolt 44 Ribbon spring holder 44a Hole 45 Connection band
45a Upper lip 45b Lower lip
45c Recessed groove 45b Slit 46 Screw 50 Magazine case 50a Hole 50b Case rib 50c Case return 52 Shaft 53 Magazine case holder
60 Joining bracket 61 Material to be tightened 100 Screw 110 Washer 112 Connecting band guide groove 114 Passage
115 Leaf spring 120 Screw 121 Screw holder
121a Guide surface 122 Screw passage 125 Cap
150 Spring 151 Ball 160 Bolt
161 Nut 200 Case cap

Claims (8)

A screw tightening tool for rotating the driver bit, a guide portion that is attached to the screw tightening tool and covers the driver bit, and a sliding portion that is movable relative to the guide portion in the axial direction of the driver bit are provided. In the screw tightening machine in which the sliding portion stores a connecting band that holds a plurality of screws, and the magazine portion that sequentially transports the screws held in the connecting band onto the axis of the driver bit is fixed.
A sleeve that is rotated by the driver bit and slidable in the axial direction is provided between the outer peripheral side of the driver bit and the guide portion,
Attach a magnet to the tip of the sleeve,
The screw held by the connecting band is attracted to the magnet, and the rotational force of the driver bit is transmitted to the screw via the sleeve;
A screw tightening machine characterized in that the screw is protruded from the sliding portion by advancing the screw by the action of a screw thread of the screw being rotated and a holding portion of the connecting band.   The screw tightening machine according to claim 1, wherein the sleeve has a cylindrical shape, and an inner peripheral side of the sleeve has a polygonal shape corresponding to an outer diameter of the driver bit.   The connecting band has an upper lip and a lower lip for holding a screw. When the sleeve is rotated, the screw rotates, and the screw advances by the action of the thread of the screw and the lower lip. 3. The screw tightening machine according to claim 2, wherein when the head of the screw reaches the lower lip, the advancement of the screw stops.   The sliding portion is provided with a gripping means for holding the tip of the screw protruding from the sliding portion, and the gripping means has two members separated in the axial direction and the vertical direction. The screw tightening machine according to claim 3.   The direction in which the sliding portion approaches the screw tightening tool by operating the screw tightening tool and pressing it in the screw direction after holding the screw with the tip of the screw protruding from the sliding portion. 5. The screw tightening machine according to claim 4, wherein the screw bit is tightened when the tip of the driver bit is engaged with the screw.   The sleeve is urged rearward in the axial direction of the driver bit by a spring means arranged between the sliding portion, and the sliding portion is arranged by the spring means arranged between the guide portion and the guide portion. The screw tightening machine according to claim 5, wherein the screwdriver is biased forward in the axial direction of the driver bit.   The screw tightening machine according to claim 6, wherein the magazine portion has a transfer means for moving the connecting band so as to approach the axis of the driver bit.   The screw tightening machine according to claim 7, wherein the sliding portion has an opening for discharging a connecting band portion that has held the tightened screw to the outside.

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