JPS635226B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic screw driver, and more particularly, an automatic screw driver that automatically feeds and drives screws by using a strip that has upright tabs on both side edges and has a number of removable screws arranged side by side. Regarding the head of

Automatic screw driving machines that drive screws while automatically feeding them into the head are already known. This screw driver uses a strip made of a flexible material, such as synthetic resin, on which a number of screws are arranged side by side at predetermined intervals, and the screws are fed by this strip. Each side edge of the strip is provided with upright tabs at predetermined intervals, each tab having a central screw retaining hole and a guide groove leading from the hole to the end of the tab. The screws are passed between the guide grooves of the tabs, and are removably held in each tab pair by being pushed into the holding holes. In this way, a strip that removably holds a number of screws at predetermined intervals is guided into the strip feed groove of the automatic screw driver head, and the screws held by the strip are aligned with the bit of the screw driver. Stop feeding the strip.
The operator completes the screw driving operation by simply pressing the head of the machine against the object to be screwed, and when the pressure is released, the strip is fed so that the next screw is aligned with the bit. Such a screw driver is convenient because the operator only has to press the head against the object.

However, such a screwdriver has a drawback in that it is not fully guaranteed that the tip of the screwdriver's bit will fit snugly into the cross groove of the screw head. In other words, even if the axes of the screw and bit are aligned, it is an accident that the tip of the bit will fit into the cross groove of the screw, and in many cases, the tip of the bit will not fit into the cross groove of the screw. As a result, good screw driving could not be achieved. In particular, in this case, when the bit rotated, it could damage the cross groove in the screw head, which could even cause the screw to become useless.

Also, if the axes of the screw and bit are even slightly misaligned, not only will the tip of the bit not fit into the cross groove of the screw, but the bit will also be unable to push the screw in the axial direction, causing the screw to tilt. The screw had fallen down inside the bit of the screw driver, causing problems with the screw driving operation.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an automatic screw driver that reliably guarantees the fit between the bit and the screw, and also ensures the feeding and stopping of the strip. That is, in order to achieve such an object, according to the present invention, a plurality of pairs of upright tabs are provided on both side edges at predetermined intervals, and a flexible strip is provided for removably holding each pair of tabs by passing a screw therethrough. A groove for guiding the strip is formed in the head, and a bit extending from the main body drives the screw into the object by pushing the head, and in the return process of the head, the strip is automatically fed and the next screw is inserted. In automatic screw driving machines, which are now capable of driving screws, the strip guide groove of the head is made approximately the same width as the strip, and the upright tab on the distal side of the head is disposed on the distal side of the groove. Even when the strip is tilted forward, a wall is formed to restrict the forward tilt of the lower part, and a screw holding plate is installed above the guide groove of the strip to hold the strip holding the screw in the guide groove. An automatic screw driver is provided, which is characterized in that a hook is attached to the bottom of the groove to prevent the strip from moving backwards, so that the bit and the screw head fit snugly together, and the screw holding plate prevents the screw from moving backwards. The posture during the fitting operation is maintained correctly, and the hook not only prevents the strip from moving backwards, but also works with the feed pawl of the automatic strip feed mechanism of the screw driver to fix and hold the strip in the proper position. The screw will no longer shift relative to the bit. This hook is preferably provided at the end of the bottom surface of the strip guide groove on the strip delivery side, and is preferably made of a spring plate. This prevents the strip from moving backwards, but allows for smooth delivery.

Preferred embodiments of the present invention will be described in detail below with reference to the drawings. An automatic screw driver 1 generally shown in FIG. 1 has a motor (not shown) built into a main body 2, and a switch 4 on a handle 3 controls the driving of the motor, and a switch 5 controls the driving of the motor. Normal rotation,
Select reverse. A clutch portion 7 is provided between the nose 6, which contains a bit for driving a screw, and the main body 2, and a clutch is provided for controlling the transmission of the rotation of the motor to the bit. Attached to the nose 6 is a driving head 10 that automatically feeds a strip 9 that holds screws 8 at predetermined intervals and drives the screws into a predetermined object with a bit.
A magazine 11 is mounted below this head, which stores the screw strip 9 in a coiled manner.

The strip 9 used in this automatic screw driver 1 is shown in detail in FIGS. 1a and 1b. The strip 9 is made of a flexible material such as synthetic resin, and has a number of pairs of upright tabs 12 provided at predetermined intervals on both side edges thereof. This tab 12 is provided with a round hole 13 in the center thereof for holding the screw 8, and a guide groove 14 having a shape that widens toward the tip for pushing the screw into the hole 13 is provided at the end. The screw 8 is passed through this groove 14 and, by being pushed in, is held in the stop as shown in FIG. 1b. This screw can also be removed by external force due to the flexibility of the stop. A hole 15 in the center of the strip is a strip feeding hole for engaging a feeding pawl of the head 10 to feed the strip.

FIG. 2 shows a side view of the head 10 of the screw driver. The head 10 is fixed to the nose 6 of the screw driver 1 by a screw 21, and a strip 9 having screws 8 arranged side by side is held and guided at the tip of the head 10. Nose 6
The clutch portion 7 between the main body 1 and the main body 1 consists of two clutch plates 22 and 23, one plate 22 is connected to the main body 1.
is connected to the rotating shaft of the motor. other board 2
3 is connected to a shaft extending in the nose direction,
A bit 24 extends into the head 10 and is connected to the tip of the shaft. A spring 25 is provided between the clutch plates 22 and 23, and when the clutch plates 22 and 23 are inactive, the plates are separated and the rotation of the motor is not transmitted to the bit. When the head is pushed to the right in FIG. 2 and the projection 26 of the clutch plate 23 presses the spring 25, the plates 22 and 23 are engaged and the bit is rotated.

The head 10 is provided with an automatic strip feeding mechanism. This automatic feeding mechanism is also shown in FIG. 3, so please refer to it as well. Upper and lower edges 33 and 34 of the housing 32 to which a mounting block 31 with screws 21 for fixing to the nose 6 is fixed.
are bent inward to form a rail for the guide groove 36 of the headblock 35, and support the headblock 35 in a slidable manner. The mounting block 31 has a lower extension 37 in which a magazine 11 containing the screw strip 9 in a coil is mounted.

A spring 38 is provided between the housing 32 and the head block 35, so that the block 35 is always
is pressed toward the tip. The block 35 shown in FIG. 3 is held in the housing 32 against the pressing force of this spring.
This is because the pin 39 attached to the housing 32 is engaged with the end of the elongated hole 40 of the housing 32. The pin 39 is attached to the tip of an arm 41, and the other end of the arm has a claw 4 that engages with the feed hole 15 of the stop.
The link arm 43 is pivotally attached to the intermediate position of the link arm 43 having a link arm 43 having a link arm 43 having a link arm 43 having a link arm 43 having a link arm 43 having a link arm 43. The link arm 43 is formed in an "L" shape, is pivotally attached to the head block 35 by a pin 44, and the other rear end is attached to a spring 45 attached to the head block 35.
The claw 42 is positioned above the elongated hole 46 of the block 35. The pawl 42 extends through an elongated hole 46 to engage a feed hole in the strip 9 fed into the guide groove. Arms 41 and 43 form a toggle mechanism so that the block 35 When pushed in the direction shown in Figure 3), the pin 39 opens into the elongated hole 4.
0 to the left in FIG. 3 and abuts on the left end. When the block 35 is further pushed, the arm 41 is raised against the upward pressing force of the arm 43, and the claw 42 is moved downward away from the feed hole 15 of the strip, as shown in FIG. 3a. When block 35 is pushed further, arm 41 collapses into another stable position, i.e. in the opposite direction to that shown in FIG. This angle of inclination is determined by the recess 47 of the block 35 that accommodates the link mechanism.
regulated by the walls of Therefore, the claw 42 at the tip of the arm 43 only moves slightly upward, but remains substantially in the vertical position. In this position, claw 4
2 engages the next feed hole 15 of the strip 9. When the pressure on the head block 35 is released, the resilient force of the spring 38 pushes the block 35 toward the tip, and the pin 39 opens the elongated hole 40 into the third
It moves to the right in Figure a, contacts the end of the elongated hole, raises the link 41, and returns to the position shown in Figure 3. At this time, the claw 42 of the arm 43 moves upward, thereby automatically feeding the strip 9. The pawl 42 is formed in a hook shape so that it locks into the feed hole 15 and feeds it only when moving upward, and loses its locking action when moving downward. The automatic strip feed mechanism does not require further explanation.

In the screw driving operation, the operator places the strip 9 with the screws 8 juxtaposed in the strip guide groove 50 of the head block 35. In this case, the feed hole 15 of the strip 9 is inserted into the pawl 42 of the arm 43 of the feed mechanism, and the screw 8 is aligned so that it coincides with the axis of the bit 24. After completing this preparation, the operator presses the tip of the head block 35 against the object to be struck. When the block 35 is pushed, the screw 8 hits the tip of the bit, and when it is pushed further, the bit pushes the screw 8, comes off the strip 9, and moves to the tip of the block 35. When pressed further, the clutch plate 23 presses the spring 25 and the other clutch plate 22
The bit rotates, causing the screw 8 to rotate and drive the screw into the required location. The head block 35 includes a gauge plate 51 for adjusting the screw driving depth and a lock screw 5 for adjusting the gauge plate 51.
2 is provided. The gauge plate 51 has a long hole 53 provided diagonally, and can be moved diagonally upward or diagonally downward by loosening the lock screw 52. When the gauge plate 51 is moved downward, the rear end of the plate protrudes rearward from the rear end of the headblock, so that even if the headblock is pushed strongly, the gauge will close before the rear end of the headblock comes into contact with the mounting block 31. The rear end of the plate abuts and limits the depth to which the headblock can be pushed.
On the other hand, the bit gradually moves to the tip by the screw driving operation, and when the screw enters a certain depth or more, the force pushing the clutch plate 23 becomes weaker and the spring 25 disengages the clutch. Therefore, by adjusting the gauge plate 51, the relative moving distance of the head block 35 to the housing 32 can be adjusted, and thereby the driving depth of the screw can be adjusted.

What is important in the invention is that the tip of the bit 24 is guaranteed to fit snugly into the cross groove of the screw 8 when it comes into contact with the head of the screw 8 and removes it from the strip. The principle of this mechanism will be explained with reference to FIGS. 4a, b, c and d. FIG. 4a is an operational diagram of a conventional automatic screw driver. The tip of the bit 24 pushes the head of the screw 8 in the direction of arrow B, tilting the tab of the strip 9 forward and removing the screw 8 from the strip 9. However, in this case, it is only by chance that the tip of the bit fits into the cross groove of the screw 8, and in many cases it is in a disengaged state. Of course, during this time the clutch does not operate, so the bit is pushed out of the strip without being seated in the cross groove of the screw. It is undesirable for the screw to be further pushed by the bit in this state, causing the bit to rotate. However, as shown in FIG. 4b, the tab (here,
(designated "F" for illustration purposes) is held upright against the pressing force of the bit. Since the screw 8 is pressed by the bit, the rear tab (indicated by "R") tilts forward, and the force that tries to knock down the tab F is transmitted to the thread of the screw. It can be converted into a force that rotates the screw as shown by the arrow c shown in c. In other words, by holding the front tab so that it does not fall over, pressing the screw will cause the screw to rotate little by little. This means that even if you press the screw without the bit being in the cross groove of the screw, the screw will rotate little by little, and this rotation will cause the tip of the bit to fit snugly into the cross groove of the screw. Figure 4d
4b is a diagram in which the finger shown in FIG. 4b is replaced with a wall W, and further shows the actual action of the tab in this case. In other words, a reaction force as shown by the dashed arrow D acts on the tab F pressed by the bit.
When the bit and cross groove match, push the screw slightly backwards and the fit will be instantaneous and tight.

The operation of an actual screw driver will be explained using FIGS. 5a, b, and c. Fig. 5a shows a state in which the tip of the head block 35 is slightly pushed toward the object P, and the tip of the bit 24 is in contact with the head of the screw 8, but it does not fit into the cross groove of the screw. It's not fitting. Guide groove 50 of strip 9
is elevated on the distal end side of the headblock so as to form the wall W of FIG. 4d. b shows the state in which the bit is pressed slightly from the state in which it is in contact with the screw. At this time, the screw 8 pressed by the bit
tries to tilt the tab 12 of the strip 9 forward. For this reason, the tab on the rear side tilts forward, but the tab on the tip side is restricted from tilting forward by the high wall of the groove 50, which causes the screw 8 to rotate and the tip of the bit to fit into the cross groove of the screw. That is, it is guaranteed that the bit will fit into the cross groove of the screw. At stages a and b, the clutch plates 22 and 23 are in a disengaged state, and the bit is not rotating. Bit 24
When pushed in further, the screw is pushed hard, causing the tab 12 of the strip 9 to tilt forward and removing the screw 8 from the strip. Then, the screw is strongly pressed against the object, and the clutch plate 23 is pushed backward through the bit and engages with the clutch plate 22, causing the bit to rotate.
This stage is shown in Figure 5c.

Furthermore, in the present invention, the strip guide groove 5
The bottom of the 0 can be tilted backwards. This is shown in FIG. The first reason for doing this is that the moment the screw locates the cross shape at the tip of the bit while it is turning, it will snap into place with force, like falling into a pit. Another reason is as follows. In other words, when the tip of the bit pushes the top of the screw head, the screw moves upward using the regulated front tab as a fulcrum, and as a result, the screw springs up from the round hole 13 of the tab 12 and moves onto the guide groove that widens at the end. Located in At this time, the axial center of the screw and the axial center of the bit are aligned, and the screw pressing force of the bit is applied straight to the screw, making it possible to drive the screw smoothly. This inclination is preferably chosen so that the angle θ in FIG. 6 is 5°. As a result, the tip of the bit comes into contact with a point 1.5 to 2 mm higher than the head of the screw, and the axis of the screw that has come out of the round hole coincides with the axis of the bit.

In addition, to prevent the screws from flying out when they are removed from the strip, the screw holding plate 55 is secured to the head block 35 using bolts 56 or the like as shown in FIG.
Attach to. This plate 55 is located on the strip guide groove 50 of the headblock 35 and also covers the screw running groove 57 of the headblock. The shape of this plate is shown in detail in FIG. The screw holding plate 55 has a main body having a block head mounting hole 58 and a screw running groove 57 at the tip of the head block.
a screw guide section 59 that extends along the tip of the strip, a strip guide section 60 that guides the strip holding the screw, and an empty strip guide section 6 that extends downward from other parts and weakly presses the empty strip with its tip.
1. In particular, it is preferred that the holding surfaces of the strip guide section 60 and the empty strip guide section be inclined at an angle .theta., as shown in FIG. 7a, to accommodate the inclined supported strip. As mentioned above, this angle is preferably about 5°. Preferably, the rear end face of plate 55 is notched in a stepwise manner to receive similar notches provided in gauge plate 51 to guide the gauge plate. Incidentally, when attaching the screw holding plate 55 to the head block 35, it is also preferable to use a spring washer or the like to impart some elasticity to the screw guide portion to allow the screws to pass smoothly.

As shown in FIG. 2, a hook 63 is provided at the upper end of the bottom surface of the strip guide groove 50 of the headblock 35, that is, at the end from which the empty strip from which the screw has been removed is fed out, to prevent the strip from moving backwards. This hook is shaped as shown in FIG. 8, and its ridge 64 is inserted into the hole 15 of the strip 9 located in the strip guide groove. The hook 63 is fixed to the bottom of the groove 50 by a screw 65 or the like, and the protruding portion 64 of the hook has a gentle slope toward the front in the direction of strip movement, and a steep slope toward the rear, thereby preventing the strip from moving backwards. To prevent.
Preferably, the hook is made of a springy material so that forward advancement of the strip is smooth. This hook does not interfere with the feeding operation by the pawl 42 of the automatic strip feeding mechanism, and moreover, the strip remains stopped by the hook during the downward movement of the pawl, and the strip feeding does not move backward. In particular, the effect of preventing backward movement is remarkable due to the cooperation of the screw holding plate 55 with the holding surface of the empty strip guide portion 61.

According to the present invention, it is guaranteed that the tip of the bit fits perfectly into the groove of the screw head in an automatic screw driver, which not only drives the screw properly but also prevents the screw from falling inside the head. The screws do not fly out, the strip is fed smoothly, and there is no reversal or return of the strip.

[Brief explanation of the drawing]

Fig. 1 is a schematic side view of an automatic screw driver, and Fig. 1 a shows a strip used in the automatic screw driver.
A partial perspective view with the screws removed; Figure 1b is a perspective view of the strip showing a pair of tabs with screws installed; Figure 2 shows the inside of the head and clutch of the automatic screw driver. Partially sectioned side view, 3rd
The figure is a partially exploded side view of the head seen from the back side of Figure 2, Figure 3a is an exploded side view showing the strip feeding mechanism of the head, and Figures 4a, b, c and d illustrate the principle of the invention. The explanatory diagrams shown in FIGS. 5a, b and c show the operation of the screw driver of the present invention.
Fig. 2 is a sectional view taken along the line V-V, Fig. 6 is a partial side sectional view of the headblock showing how the bottom surface of the strip guide groove is inclined, Fig. 7 is a plan view of the screw holding plate, Fig. 7 7a is a side view of the plate shown in FIG. 7 as seen from arrow E, and FIG. 8 is a perspective view of the hook. 1... Automatic screw driver, 6... Nose, 7...
Clutch part, 8...Screw, 9...Strip, 1
0...Head, 11...Strip storage magazine, 12...Tab, 22, 23...Clutch plate,
24...Bit, 32...Head housing, 3
5...Head block, 37...Mounting block, 39...Pin, 41, 43...Toggle arm, 42...Claw, 50...Strip guide groove, 5
5...Screw holding plate, 57...Screw running groove, 61...
...Empty strip guide section, 63...Hook.

Claims (1)

[Claims] 1. A flexible strip is used, in which a large number of pairs of upright tabs are provided at predetermined intervals on both side edges, and a screw is passed through each tab pair to removably hold the strip, and the strip is guided. A groove is formed in the head to allow the screw to be driven into the object by pushing the head into the bit extending from the main body, and the strip is automatically fed during the return process of the head so that the next screw can be driven. In automatic screw driving machines,
The strip guide groove of the head is made approximately the same width as the strip, and on the distal end side of the groove there is a wall that restricts the forward inclination of the lower part even if the upright tab on the distal end of the head is tilted forward in the upper part. A screw holding plate is attached to the head above the strip guide groove to hold the strip holding the screw in the guide groove, and a hook is installed on the bottom of the strip guide groove to prevent the strip from moving backwards. An automatic screw driver characterized in that it is equipped with. 2. The screw driving machine according to claim 1, wherein the hook is provided at the end of the bottom surface of the strip guide groove on the strip delivery side. 3. The screw driver according to claim 2, wherein the hook is made of a spring material.