Driving device for screw member

Abstract

This driving device for a screw member comprises a screw feeding part, a screw holding part, a driver (19), and an advancing / retreating device. The screw feeding part feeds the screw member, in which a tool engagement part is formed at one end in the axial direction, to a driving position for the screw member. The screw holding part holds the screw member fed from the screw feeding part in a fixed posture. The driver (19) holds a tool engaged with the tool engagement part and rotates the tool. The advancing / retreating device causes the driver (19) to perform an advancing / retreating operation in a direction along the axial direction of the screw member. The screw holding part is provided with a holding release mechanism that releases the holding of the screw member when the driver (19) approaches the screw member by a predetermined distance or more.

Description

Screw member driving device

[0001] The present invention relates to a screw driving device for driving a screw into a workpiece. This application claims priority to Japanese Patent Application No. 2024-089372, filed on May 31, 2024, the contents of which are incorporated herein by reference.

[0002] A screw member may be driven into a target member to fasten a member such as a building material or to reinforce the interlayer of a layered mortar member. Various screw member driving devices have been proposed for use in such cases (see, for example, Patent Documents 1 and 2).

[0003] Patent Literature 1 describes a technique for building a structure by layering cementitious materials using a construction 3D printer, and for driving rod-shaped reinforcing members into the structure during this process. This technique allows for reinforcement between the layers of material by driving rod-shaped reinforcing members into the layered structure, thereby increasing the strength of the completed structure.

[0004] However, the technique described in Patent Document 1 involves simply driving rod-shaped reinforcing members into a layered structure, which makes it difficult to drive the reinforcing members as desired once the cement-based material begins to harden over time.

[0005] The driving device described in Patent Document 2 includes a feeder that feeds screws (screw members), a holding mechanism that holds the fed screws, and a driver that tightens the screws held by the holding mechanism while advancing them toward the workpiece. The holding mechanism includes multiple spherical holding parts that hold the shank of the screw fed from the feeder from the outer periphery, and a biasing spring that presses each holding part against the outer periphery of the screw. The holding mechanism presses the multiple holding parts against the outer periphery of the shank of the screw using the spring force of the biasing spring, thereby holding the screw in a fixed position.

[0006] When this driving device is used to drive a screw into a workpiece, the screw is held in a fixed position by the holding mechanism (multiple holding components), and the screw head is tightened with a screwdriver. The driver rotates the screw in the screw-driving direction while advancing the tool toward the workpiece. As the screw is driven into the workpiece, the multiple holding components of the holding mechanism are pressed radially outward by the screw head. As a result, each holding component moves radially outward against the biasing force of the biasing spring, allowing the screw head to be tightened further.

[0007] JP 2021-194790 A JP 2010-142900 A

[0008] However, the driving device described in Patent Document 2 is designed to use the head of the screw to press multiple retaining components radially outward, thereby releasing the screw from the retaining mechanism. This makes it difficult to smoothly move the retaining components using the head of the screw when handling large screws. Therefore, in order to achieve a smooth driving operation, this driving device significantly limits the shape and size of the screws it can handle.

[0009] SUMMARY OF THE INVENTION The present invention provides a screw driving device that can smoothly drive a screw into a target member regardless of the shape or size of the screw being handled.

[0010] A screw member driving device according to one embodiment of the present invention comprises a screw feed unit that feeds a screw member having a tool engagement portion formed at one axial end to a driving position for the screw member, a screw holding unit that holds the screw member fed from the screw feed unit in a fixed position, a driver that holds a tool engaged with the tool engagement portion and rotates the tool, and an advancing / retracting device that moves the driver forward and backward in the axial direction of the screw member, and the screw holding unit is equipped with a hold release mechanism that releases the driver's hold on the screw member when the driver comes closer than a predetermined distance to a member into which the screw member is to be driven.

[0011] When a screw is driven into a workpiece using the driving device of this embodiment, the screw feeder feeds the screw one by one. When the screw is fed to the screw holder, the screw holder holds the screw in a fixed position. Next, the driver is advanced toward the screw by the forward / backward movement device, and the tool held by the driver is engaged with the tool engagement portion of the screw. In this state, the driver is further advanced while the tool is rotated in the tightening direction by the driver. As a result, the screw is tightened into the workpiece while being held in a fixed position by the screw holder. As the driver continues to tighten the screw, when the driver approaches the workpiece by a predetermined distance or more, the release mechanism of the screw holder is activated, releasing the screw. When the driver then further tightens the screw, the screw is tightened into the workpiece without being restrained by the holder. At this time, the screw is already tightened to a certain depth into the workpiece, so it is tightened in a stable position relative to the workpiece. In this type of driving device, when the driver approaches the workpiece to be driven into more than a predetermined distance, the hold-release mechanism releases the hold on the screw member, making it possible to smoothly drive the screw member into the workpiece to be driven into regardless of the shape or size of the screw member being handled.

[0012] In the above configuration, the predetermined distance is preferably a distance at which the screw member is driven into the target member to a specified depth.

[0013] In this case, once the screw is driven to a specified depth into the workpiece, the retaining portion releases the screw. Therefore, even after the retaining portion releases the screw, the screw can be tightened into the workpiece while maintaining a stable position. This prevents the screw from tilting and prevents gaps from forming between the screw and the workpiece.

[0014] In the above configuration, the screw holding portion comprises a plurality of gripping claws that can abut against the outer peripheral surface of the shank of the screw member, a biasing portion that biases the gripping claws in a direction pressing them against the outer peripheral surface of the shank, an operating piece that moves back and forth integrally with the driver, and a cam block that receives a pressing force from the operating piece and moves the gripping claws in a direction away from the outer peripheral surface of the shank when the driver approaches the target workpiece by more than a predetermined distance, and the operating piece and the cam block may form the hold release mechanism.

[0015] In this case, in the screw holding portion, multiple gripping claws are pressed against the outer peripheral surface of the shank of the screw member by the biasing portion. The screw member is thereby gripped by the multiple gripping portions. In this state, as the screw member is tightened by the driver, when the driver approaches the target member by more than a predetermined distance, the operating piece, which advances with the driver, abuts against the cam block. This activates the cam block, moving the gripping claws away from the outer peripheral surface of the shank of the screw member. When this configuration is adopted, it is possible to release the screw member from its hold as the driver moves, despite the simple configuration.

[0016] In the above configuration, it is preferable that the hold release mechanism includes an adjustment mechanism that can change the predetermined distance.

[0017] In this case, the distance between the target element and the driver when the retention release mechanism begins to release the retention of the screw element can be appropriately adjusted by the adjustment element.

[0018] In the above configuration, it is desirable that the predetermined distance be determined in accordance with the object of driving.

[0019] In this case, it becomes possible to suitably drive the screw member into the target member depending on the material, density, specific progress of hardening, etc. of the target member.

[0020] In the above configuration, a base block may be provided on which the advance / retract device and the driver are installed, and the screw feed unit may be formed by a cartridge that can be loaded with a large number of the screw members and may be removably attached to the base block.

[0021] In this case, since the screw feeder is configured with a cartridge that can be loaded with multiple screws, additional screws can be loaded efficiently by replacing the cartridge. Also, by loading multiple cartridges with screws of different sizes and shapes, it becomes possible to easily switch to driving screws of different sizes and shapes by simply replacing the cartridge.

[0022] In the above configuration, the threaded member may have a female thread formed on one axial end surface and a male thread formed on the other axial end surface, the male thread having a shape complementary to the female thread.

[0023] In this case, after one screw member is driven by the driving device, the male thread on the other axial end of the next screw member to be driven can be threadedly connected to the female thread on one axial end face of the screw member. When the next screw member is tightened by the driving device in this state, the previously driven screw member is further tightened together with the next screw member. Therefore, when this configuration is adopted, it is possible to easily drive any number of screw members into a target member in a connected state.

[0024] In the above configuration, the target member into which the screw member is driven may be a mortar member shaped in a layered state.

[0025] In this case, when the screw member is driven into the mortar member by the driving device, the driven screw member reinforces the interlayer of the mortar member. At this time, the screw member penetrates the interlayer of the mortar member by tightening, so it can be driven even when the mortar member has hardened to a certain extent. Furthermore, the screw member has a spiral groove on the outer periphery of its shank, which further strengthens the reinforcement between the layers of the mortar member. Furthermore, the driving device holds the screw member in a fixed position by the screw holding portion until it is tightened into the mortar member to a certain extent, thereby suppressing tilting and vibration of the shank of the screw member. Furthermore, after the screw member is tightened into the mortar member to a certain extent, the screw holding portion releases the screw member from its grip, thereby reducing resistance in the later stages of tightening the screw member. This allows the screw member to be driven smoothly into the mortar member.

[0026] According to the above-described screw driving device, it is possible to smoothly drive a screw into a target member regardless of the shape or size of the screw being handled.

[0027] 1 is a perspective view of a driving device according to an embodiment; a front view of a driving device according to an embodiment; a perspective view of a driving device according to an embodiment with some components removed; a perspective view of a portion of a screw feeding unit and a screw holding unit according to an embodiment; a perspective view showing an enlarged portion of a feed belt according to an embodiment; a perspective view of a portion of a screw holding unit according to an embodiment; a front view of a screw holding unit according to an embodiment; a front view showing an operating state of the screw holding unit according to an embodiment; a cross-sectional view showing a state in which a screw member according to an embodiment has been driven into a member to be driven; a cross-sectional view showing a state in which a screw member according to another embodiment has been driven into a member to be driven; a cross-sectional view showing a state in which a screw member according to another embodiment has been driven into a member to be driven; a cross-sectional view showing another use form of a driving device according to an embodiment.

[0028] Next, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, common parts are designated by the same reference numerals, and some overlapping descriptions will be omitted.

[0029] FIG. 1 is a perspective view of a screw driving device 10 (hereinafter simply referred to as the "driving device 10") according to this embodiment. FIG. 2 is a front view of the driving device 10. FIG. 9 is a cross-sectional view showing a state in which a screw 11 has been driven into a target member 1. As shown in FIG. 9, the driving device 10 of this embodiment drives the screw 11 into the target member 1 while applying a rotational force, thereby driving the shank 11a of the screw 11 into the target member 1. The target member 1 may be, for example, a layered mortar member (concrete-based member). In this case, when driving the screw 11 into the target member 1, the screw 11 can be suitably driven into a layered mortar member (concrete-based member) that has not yet hardened or has an inconsistent hardness. However, the layered mortar member (concrete-based member) described here is merely an example of the target member 1, and the target member 1 is not limited to this.

[0030] 9 shows a portion of a structure created using a 3D printer for mortar (concrete-based materials). This portion of the structure is designated as the target component 1. The driving device 10 can be used alone, or, for example, connected to a 3D printer for mortar. In this case, for example, mortar can be continuously applied using the 3D printer, and the driving device 10 can drive the screw member 11 at an appropriate timing when the mortar is layered.

[0031] In this embodiment, the screw member 11 has a shank 11a having a threaded outer surface and a head 11b connected to one axial end of the shank 11a. A tool engagement groove 12 (see FIGS. 4 and 6 ), such as a cross recess or a slot, is formed on the end surface of the head 11b. An engagement blade 13a at the tip of a rotary tool 13, which is a tightening tool, can be engaged with the tool engagement groove 12. The screw member 11 is not limited to the above-described shape, and may have any shape as long as the tool engagement groove 12 (engagement hole (e.g., hexagonal socket)) is formed on the end surface of the head 11b. For example, any type of screw can be used, such as a flat head screw, pan head screw, truss screw, wood screw, or universal screw.

[0032] In this embodiment, the tool engagement groove 12 constitutes the tool engagement portion. However, the tool engagement portion is not necessarily limited to a groove, and may be a polygonal hole, a polygonal convex portion, or the like, as long as it can be coupled to the rotary tool 13 so as to be rotatable together with the rotary tool 13.

[0033] As shown in Figures 1 and 2, the driving device 10 has a base block 14 that connects to a mortar 3D printer (not shown). The base block 14 includes a skeleton frame 15 assembled in a generally rectangular parallelepiped shape, a top plate 16 installed generally horizontally on top of the skeleton frame 15, and a connecting frame 9 extending upward from the back of the skeleton frame 15. The connecting frame 9 is connectable to a mortar 3D printer (not shown). For ease of explanation, the side of the skeleton frame 15 on which the connecting frame 9 is located will be defined as the "rear" and the opposite side will be defined as the "front." An arrow FR pointing to the front and an arrow RR pointing to the rear are shown in appropriate locations in the drawings.

[0034] The driving device 10 includes a screw feed unit 17 that loads a plurality of screw members 11 and feeds the loaded screw members 11 one by one to the driving position, a screw holding unit 18 that holds the screw members 11 fed from the screw feed unit 17 in a fixed position, a driver 19 that holds a rotary tool 13 for fastening and rotates the rotary tool 13, and an elevating device 20 that moves the driver 19 up and down. In this embodiment, the screw feed unit 17 constitutes a screw feed section, and the screw holding unit 18 constitutes a screw holding section. The elevating device 20 constitutes an advancing and retracting device that moves the driver 19 up and down in the axial direction of the screw members 11.

[0035] The screw feeding unit 17 and the screw holding unit 18 are connected to a lower region of the skeletal frame 15 of the base block 14. The lifting device 20 is fixedly installed on the upper surface of the top plate 16. The driver 19 is attached to a movable block 21 of the lifting device 20. The driver 19 is attached to the movable block 21 so that the rotary tool 13 it holds faces vertically downward. The driver 19 rotates the rotary tool 13 by an electric motor, air motor, or the like (not shown).

[0036] The lifting device 20 includes a lifting support column 22 that stands vertically above the top plate 16 and supports the movable block 21 so that it can be raised and lowered, a rotary actuator 23 that is fixed to the upper surface of the top plate 16, and a motion conversion unit (not shown) such as a rack and pinion mechanism that converts the power of the rotary actuator 23 into the lifting and lowering motion of the movable block 21. The rotary actuator 23 can be, for example, an electric motor or an air motor.

[0037] An operation piece 25 for pressing a pair of cam blocks 24 (described in detail later) is attached to the movable block 21, which is moved up and down by the rotary actuator 23. The operation piece 25 has tapered pressing surfaces 25a (see FIGS. 7 and 8) formed on the front and rear side surfaces of the lower end. The main portion of the operation piece 25 (the portion including the pair of pressing surfaces 25a) is disposed adjacent to the side of the rotary tool 13 held by the driver 19.

[0038] A substantially rectangular opening 26 is formed on the top plate 16 at a position facing the movable block 21 in the vertical direction. This opening 26 allows the rotary tool 13 and the operating piece 25 to move below the top plate 16 when the movable block 21 moves downward. The rotary tool 13 tightens the screw member 11 below the top plate 16.

[0039] Figure 3 is a perspective view of the driving device 10 with some components removed. Figure 4 is a perspective view showing a portion of the screw feed unit 17 and the screw holding unit 18. Reference numeral 27 in Figure 3 denotes a support beam attached to the skeletal frame 15 of the base block 14. This support beam 27 extends in a direction perpendicular to the front-to-rear direction of the skeletal frame 15, and is detachably connected to the skeletal frame 15 near both ends in the extension direction. The screw feed unit 17 and the screw holding unit 18 are attached to this support beam 27.

[0040] As shown in Fig. 3, the screw feeding unit 17 includes a guide frame 28 that is oval in top view, a pair of upper and lower feed belts 29 arranged below the guide frame 28, a pair of sprockets 30 (see Fig. 4) that rotate the feed belts 29, and a drive motor (not shown) that rotates one of the sprockets 30. The guide frame 28 and the upper and lower feed belts 29 are covered on the outside by a unit casing 31 (see Figs. 1 and 2). The pair of sprockets 30 are rotatably supported by the unit casing 31 and other frame members.

[0041] FIG. 5 is an enlarged perspective view of a portion of the feed belt 29. In FIGS. 3 and 4, the feed belt 29 is shown in a simplified schematic view. The feed belt 29 shown in FIG. 5 is an enlarged view of the portion indicated by the phantom line in FIG. 4. The feed belt 29 of this embodiment is formed by a metal roller chain. The feed belt 29 shown in FIG. 5 includes outer links 52 each having two outer plates 50 connected at their ends by a pin 51, and inner links 55 each having two inner plates 53 connected at their ends by a bushing 54. The outer links 52 and the inner links 55 are alternately connected. The pin 51 of the outer link 52 is assembled to the bushing 54 of the inner link 55 so as to be rotatable relative to each other. This allows bending between adjacent outer links 52 and inner links 55.

[0042] A substantially rectangular parallelepiped attachment block 56 protrudes from the outer side of the outer plate 50 of each outer link 52 in the circumferential direction (the circumferential direction of the feed belt 29). A substantially constant gap is maintained between adjacent attachment blocks 56 in the circumferential direction of the feed belt 29. This gap between the attachment blocks 56 forms a retaining groove 32, which will be described later. Note that although the feed belt 29 in this embodiment is formed by a metal roller chain, the material and structure of the feed belt 29 are not limited thereto. The material of the feed belt 29 may be, for example, resin or rubber. The material of the feed belt 29 may be any material as long as it is strong enough to be rotated by the sprocket 30.

[0043] The guide frame 28 is formed in a generally annular, oval shape. An insertion hole 28a is formed through the guide frame 28 in the vertical direction. The insertion hole 28a is formed to generally follow the oval outer shape of the guide frame 28. The shanks 11a of the multiple screw members 11 loaded into the screw feed unit 17 are inserted into the insertion hole 28a. The heads 11b of the screw members 11, whose shanks 11a are inserted into the insertion hole 28a, are engaged with the upper side edge of the insertion hole 28a. This prevents the screw members 11 from falling downward. However, an opening (not shown) is formed at the location where the screw members 11 are tightened (driven) by the rotary tool 13 to allow the heads 11b of the screw members 11 to pass through. This opening is formed to be continuous with the insertion hole 28a. The opening is formed at a generally central position on the major axis side of the oval guide frame 28. The screw feeding unit 17 has a driving (fastening) position for the screw member 11 at approximately the center position on the major axis side.

[0044] Each of the upper and lower feed belts 29 is stretched over a pair of sprockets 30, giving the entire belt an oval shape that roughly follows the oval shape of the guide frame. A plurality of retaining grooves 32 are formed on the outer periphery of each feed belt 29, penetrating vertically and opening outward. The retaining grooves 32 are formed at approximately equal intervals along the circumferential direction of each feed belt 29. The retaining grooves 32 of the upper and lower feed belts 29 are aligned vertically. The shanks 11a of the screws 11, whose heads 11b are locked by the guide frame 28, are inserted vertically into the corresponding retaining grooves 32. The screws 11 are pre-loaded into the retaining grooves 32 of the upper and lower feed belts 29 with their heads 11b locked to the guide frame 28. When the upper and lower feed belts 29 receive power from the sprockets 30 and move around in a fixed direction at a fixed pitch, the screws 11 loaded in the screw feed unit 17 are fed one by one to the driving position (tightening position).

[0045] The screw feed unit 17 configured as described above is configured as a cartridge that is detachable from the base block 14. When replenishing the screw member 11 to be used or when using a different screw member 11 of a different shape or size, the cartridge of the feed unit 17 can be replaced as a whole. The screw feed unit 17 of this embodiment is formed in an oval shape, with the approximate center of the long diameter of the oval being the driving position (tightening position) for the screw member 11. This results in good overall weight balance centered on the driving position (tightening position) for the screw member 11. Therefore, even when connected to a 3D printer device for mortar, the operational balance of the 3D printer device for mortar can be maintained well.

[0046] Figure 6 is a perspective view of a portion of the screw holding unit 18. Figure 7 is a front view of the screw holding unit 18. In the following description of the screw holding unit 18, the left and right directions in Figure 7 are defined as the left-right direction. However, the left-right direction in Figure 7 corresponds to the front-rear direction of the driving device 10 when the screw holding unit 18 is attached to the base block 14. The screw holding unit 18 includes a downwardly facing, generally U-shaped connecting bracket 33 connected to the support beam 27 (see FIG. 3), a pair of left and right fixed bases 34 fixed to the left and right ends of the connecting bracket 33, gripping claws 35 supported on opposing portions of the left and right fixed bases 34 so as to be movable forward and backward, standing arms 36 protruding upward from the bases of the gripping claws 35, cam blocks 24 connected to opposing surfaces at the upper ends of the pair of standing arms 36, a biasing spring 37 that biases the left and right gripping claws 35 and standing arms 36 inward in the left-right direction, and the above-mentioned operating piece 25 (see FIG. 7) that moves up and down integrally with the driver 19. The screw holding unit 18 may include a mechanism for adjusting the guide length of the screw 11 from the surface of the target workpiece 1 to the lower ends of the gripping claws 35 that hold the screw 11 to an appropriate length.

[0047] In this embodiment, at least one of the vertical fixed position of the gripping claw 35 relative to the standing arm 36 and the fixed position of the lower end of the standing arm 36 relative to the gripping claw 35 is adjustable. These position adjustments may be achieved, for example, by providing a plurality of insertion holes in the vertical direction through which the shanks of the fastening bolts can be inserted, allowing the insertion hole through which the shanks of the fastening bolts can be inserted as appropriate. The adjustment mechanism for changing the "predetermined distance" at which the hold release mechanism starts the release operation is configured by this mechanism. However, the adjustment mechanism for changing the "predetermined distance" is not limited to this, and may have any structure that can adjust the vertical height position of the gripping claw 35. The adjustment mechanism for changing the "predetermined distance" may be a mechanism that adjusts the height of the fixed portion of the connecting bracket 33. Furthermore, the adjustment mechanism for changing the "predetermined distance" may be a mechanism that adjusts the fixed position of the operating piece 25 relative to the movable block 21.

[0048] Each of the left and right gripping claws 35 is guided by a guide mechanism (not shown) and supported on the corresponding left and right fixed bases 34 so as to be movable in the left-right direction. In this state, each of the left and right gripping claws 35 is biased inward in the left-right direction by a biasing spring 37. The direction in which the left and right gripping claws 35 face each other (left-right direction) is perpendicular to the feed direction of the screw member 11 fed to the driving position by the screw feed unit 17. The front and rear corners of the gripping surface of each gripping claw 35 in the feed direction of the screw member 11 are arc-shaped to facilitate insertion of the shank 11a of the screw member 11 between the two gripping claws 35. The pair of gripping claws 35 is disposed between the upper and lower feed belts 29 of the screw feed unit 17.

[0049] When the left and right gripping claws 35 are closed by the biasing force of the biasing spring 37, and the shank 11a of the screw 11 is pressed against the ends (arc-shaped portions) of the gripping surfaces of the left and right gripping claws 35 by the feeding of the feed unit 17, the shank 11a of the screw 11 pushes the left and right gripping claws 35 open to the left and right. When the shank 11a of the screw 11 moves to a predetermined position (driving position), the shank 11a is gripped in a fixed position by the left and right gripping claws 35. At this time, the shank 11a of the screw 11 is maintained in a vertically oriented position. At this time, the head 11b of the screw 11 is positioned above the aforementioned opening of the guide frame 28. Therefore, when the head 11b of the screw 11 is pressed from above, the head 11b of the screw 11 can be displaced downward through the opening to the guide frame 28.

[0050] The cam blocks 24 have load bearing surfaces 24a formed on their left-right inward surfaces, which slope upward and outward in the left-right direction. The left and right cam blocks 24 are subjected to the biasing forces of the corresponding left and right biasing springs 37 via the standing arms 36. The load bearing surfaces 24a of the left and right cam blocks 24 are located directly below the operation pieces 25 supported by the movable block 21. When the operation pieces 25 are lowered to a predetermined position together with the rotary tool 13 due to downward displacement of the movable block 21, the pressing surfaces 25a of the operation pieces 25 come into contact with the load bearing surfaces 24a of the left and right cam blocks 24.

[0051] Note that the tip (engagement blade 13a) of the rotary tool 13 first comes into contact with the head 11b of the screw 11 and engages with the tool engagement groove 12 of the head 11b before the movable block 21 descends and the operating piece 25 comes into contact with the left and right cam blocks 24. At this time, the driver 19 is rotated. As a result, the rotary tool 13 applies a tightening force to the screw 11 while pressing downward the head 11b of the screw 11 held by the left and right gripping jaws 35. As a result, the screw 11 is driven into the workpiece 1 with the tip of the shank 11a screwed into it while the outer surface of the shank 11a slides between the left and right gripping jaws 35.

[0052] The timing at which the pressing surface 25a of the operating piece 25 comes into contact with the load receiving surfaces 24a of the left and right cam blocks 24 as the movable block 21 descends is set to the timing after the tip side of the shank 11a of the screw member 11 has been driven in to a certain extent or more (the timing at which the screw member 11 has been driven to a specified depth into the workpiece 1 into which it is to be driven). In other words, when the driver 19 approaches the workpiece 1 into which the screw member 11 is to be driven in by a predetermined distance or more, the pressing surface 25a of the operating piece 25 comes into contact with the load receiving surfaces 24a of the left and right cam blocks 24, and release of the screw member 11 from its hold is initiated.

[0053] FIG. 8 is a front view similar to FIG. 7 , illustrating the operating state of the screw holding unit 18 when the operating piece 25 descends together with the rotary tool 13. As the operating piece 25 continues to descend after the pressing surface 25 a of the operating piece 25 abuts against the load-receiving surfaces 24 a of the left and right cam blocks 24 as described above, the operating piece 25 pushes the left and right cam blocks 24 apart in the left-right direction against the biasing force of the biasing spring 37, as shown in FIG. 8 . This causes the left and right corresponding gripping claws 35 connected to the left and right cam blocks 24 via the upright arms 36 to be displaced in the left-right direction. At this time, the distance between the left and right gripping claws 35 becomes equal to or greater than the outer diameter of the head 11 b of the screw 11. As a result, the left and right gripping claws 35 release their grip on the screw 11.

[0054] The "predetermined distance" at which the grip of the screw member 11 is released may be varied depending on the hardness, density, moisture content, etc. of the workpiece 1 to be driven. For example, if the workpiece 1 to be driven has a low hardness (soft), low density, and high moisture content, the grip of the screw member 11 may be released after the screw member 11 has been driven to a relatively deep, specified position; if the workpiece 1 to be driven has a high hardness (hard), high density, and low moisture content, the grip of the screw member 11 may be released after the screw member has been driven to a relatively shallow, specified position. Note that a sensor for measuring the hardness, density, moisture content, etc. of the workpiece 1 to be driven and an actuator for adjusting the "predetermined distance" may be provided, and the "predetermined distance" may be adjusted by the actuator in accordance with the value detected by the sensor.

[0055] Thereafter, when the screw 11 is further tightened by the rotary tool 13, the screw 11 is smoothly tightened into the workpiece 1 without being restrained by the screw holding unit 18. The screw 11 is ultimately tightened (driven) to a position where the head 11b contacts the workpiece 1, as shown in Fig. 9. In this embodiment, the operating piece 25 that moves up and down together with the driver 19 and the left and right cam blocks 24 connected to the gripping claws 35 constitute a retention release mechanism that releases the gripping claws 35 from holding the screw 11.

[0056] Once the screw 11 has been driven into the workpiece 1, the lifting device 20 is operated to raise the rotary tool 13 together with the driver 19 to the initial position. As a result, the operating piece 25 releases the pressure on the cam block 24, and the left and right gripping claws 35 are returned to their initial positions by the biasing force of the biasing spring 37. The screw feed unit 17 then rotates the upper and lower feed belts 29 to move the next screw 11 held in the holding groove 32 to the driving (fastening) position.

[0057] As described above, in the driving device 10 of this embodiment, the screw holding unit 18 (screw holding portion) is provided with a hold release mechanism that releases the hold on the screw 11 when the driver 19 approaches the workpiece 1 within a predetermined distance. Therefore, when the screw 11 is tightened, the head 11b of the screw 11 does not interfere with the gripping claws 35 of the screw holding unit 18. Therefore, when the driving device 10 of this embodiment is used, the screw 11 can be smoothly driven into the workpiece 1 regardless of the shape or size of the screw 11 being handled.

[0058] Furthermore, in the driving device 10 of this embodiment, the "predetermined distance" at which the screw 11 is released from its hold is set to the distance at which the screw 11 is driven to a specified depth into the workpiece 1. Therefore, even after the screw holding unit 18 releases the screw 11 from its hold, the screw 11 can be stored in the workpiece 1 while maintaining a stable posture. Therefore, when the driving device 10 of this embodiment is used, it is possible to prevent the screw 11 from tilting, the creation of a gap between the screw 11 and the workpiece 1, and other problems from occurring.

[0059] In this embodiment, the screw holding unit 18 (screw holding portion) includes a pair of gripping claws 35, a biasing spring 37 (biasing portion) that biases the gripping claws 35, an operating piece 25 that rises and falls integrally with the driver 19, and a cam block 24 that receives a pressing force from the operating piece 25 and moves the gripping claws 35 away from the driver 19 when the driver 19 approaches the workpiece 1 by more than a predetermined distance. The holding release mechanism is made up of the operating piece 25 and the cam block 24. Therefore, the driving device 10 of this embodiment has a simple configuration, yet can reliably release the hold of the screw member 11 as the driver 19 rises and falls.

[0060] The driving device 10 of this embodiment also includes an adjustment mechanism that can change the "predetermined distance" at which the screw member 11 is released from its grip. Therefore, when this configuration is employed, the adjustment mechanism can be used to appropriately adjust the distance between the workpiece 1 to be driven and the driver 19 when the release mechanism (operating piece 25 and cam block 24) begins to release the screw member 11 from its grip.

[0061] Furthermore, in this case, if the "predetermined distance" is determined according to the hardness, density, moisture content, etc. of the target component 1, it becomes possible to drive the screw member 11 into the target component 1 in an appropriate manner according to the material, density, specific progress of hardening, etc. of the target component 1.

[0062] Furthermore, in the driving device 10 of this embodiment, the screw feed unit 17 (screw feed section) is configured with a cartridge that can be loaded with a large number of screws 11, and this cartridge is detachably attached to the base block 14. Therefore, when the driving device 10 of this embodiment is used, additional screws 11 can be efficiently loaded by replacing the cartridge. Furthermore, by loading multiple cartridges with screws 11 of different sizes and shapes, it is also possible to easily switch between driving screws 11 of different sizes and shapes by simply replacing the cartridge.

[0063] Furthermore, in the driving device 10 of this embodiment, the target component 1 into which the screw member 11 is driven is a mortar component shaped in a layered state. When the driving device 10 drives the screw member 11 into the mortar component, the driven screw member 11 can efficiently reinforce the interlayers of the mortar component. In particular, because the screw member 11 penetrates the interlayers of the mortar component when tightened, it can be driven even when the mortar component has hardened to a certain extent. Furthermore, the spiral groove on the outer periphery of the screw member 11 further strengthens the interlayer reinforcement of the mortar component. Furthermore, although the degree of hardening of mortar varies depending on the environment, location, time, etc., the driving device 10 of this embodiment holds the screw member 11 in a constant position using the screw holding unit 18 until it is tightened an optimal distance into the mortar component (target component 1). This suppresses tilting and wobble of the shank 11a of the screw member 11, thereby preventing gaps from forming between the mortar component and the screw member 11. Furthermore, when the driving device 10 of this embodiment is used, once the screw member 11 has been fastened to a certain extent into the mortar member, the screw holding unit 18 releases the screw member 11 from its hold, thereby reducing resistance in the later stage of fastening the screw member 11. Therefore, when the driving device 10 of this embodiment is employed, the screw member 11 can be smoothly driven into the mortar member.

[0064] <Another embodiment> Fig. 10 is a cross-sectional view showing a state in which one screw member 111 of another embodiment has been driven into a workpiece 1 to be driven. Fig. 11 is a cross-sectional view showing a state in which two screw members 111 of another embodiment have been driven in series into a workpiece 1 to be driven. In this embodiment, the screw member 111 handled is different from that of the above-described embodiment. The screw member 111 of this embodiment does not have a protruding head portion on the outside, and has a female thread 40 formed on one axial end surface together with a tool engagement groove 12. A male thread 42 having a shape complementary to the female thread 40 is formed on the other axial end of the screw member 111. Therefore, the screw member 111 can be used singly as shown in Fig. 10, or two or more screw members 111 can be used connected in series as shown in Fig. 11.

[0065] Specifically, when two screw members 111 are connected in series, after the first screw member 111 is driven by the driving device, the male thread 42 on the other axial end side of the next screw member 111 to be driven can be threadedly connected to the female thread 40 on one axial end face of the first screw member 111. When the next screw member 111 is fastened by the driving device 10 in this state, the previously driven screw member 111 is further fastened together with the next screw member 111. Therefore, when the screw members 111 of this embodiment are used, it is possible to easily drive any number of screw members 111 in a connected state into the target member 1.

[0066] <Another Use of the Driving Device of the Embodiment> Figure 12 is a cross-sectional view showing a use of the driving device 10 of the embodiment for removing a screw 11 from a workpiece 1 to be driven. With the driving device 10 of the embodiment, when the driver is closer to the workpiece 1 to be driven by a predetermined distance or more, the left and right gripping claws 35 are pushed apart by the pressing action of the cam block by the operating piece. When removing the screw 11, as shown in Figure 12(a) , the rotary tool 13 is lowered to its lowest position, and the engagement blade 13a of the rotary tool 13 is engaged with the tool engagement groove 12 in the head 11b of the screw 11. Next, in this state, the rotary tool 13 is raised upward while being rotated in the direction opposite to the tightening direction. At this time, the screw 11 rises together with the rotary tool 13 while rotating in the loosening direction.

[0067] When the rotary tool 13 is raised to a certain height, the operating piece moves away from the cam block, and the left and right gripping claws 35 resume gripping of the screw 11, as shown in FIG. 12(b). At this time, the screw 11 is maintained in a stable vertical position by the left and right gripping claws 35 gripping the shank 11a. Therefore, when the rotary tool 13 continues to rotate in the direction opposite to the tightening direction, the screw 11 can be raised to a predetermined position while maintaining the stable position, as shown in FIGS. 12(b) and 12(c). Therefore, the screw 11 that has been pulled out of the workpiece 1 can be returned, for example, to the holding position of the screw holding unit.

[0068] The present invention is not limited to the above-described embodiment, and various design modifications are possible without departing from the spirit of the present invention. For example, in the above-described embodiment, a pair of gripping claws 35 are provided to grip the shank 11 a of the screw member 11, but the number of gripping claws 35 may be three or more as long as it is two or more.

[0069] Furthermore, in the above embodiment, the screw holding unit 18 (screw holding portion) is configured as a cartridge that is detachable from the base block 14, but the screw holding unit 18 (screw holding portion) does not necessarily have to have a structure that is detachable from the base block 14. Furthermore, in the above embodiment, a collet-type urging spring is used as the urging portion that urges the gripping claws 35, but the urging portion is not limited to this configuration. The urging portion may be a mechanical spring other than the collet-type, a spring that uses air pressure, or the like.

[0070] In addition, in the above embodiment, a cam-operated release mechanism including the operating piece 25 and the cam block 24 is used as the hold release mechanism, but the configuration of the hold release mechanism is not limited to this. Various other mechanisms can be used as the hold release mechanism as long as they can open and operate the gripping claws at a predetermined timing in conjunction with the downward movement of the screwdriver.

[0071] Furthermore, in the above embodiment, the driving device 10 drives the screw member 11 perpendicular to the surface of the target workpiece 1, but the screw member 11 may be driven into the target workpiece 1 at an angle other than perpendicular to the surface. In this case, the entire driving device 10 may be tilted, or the base block 14 or a portion thereof may be tilted by a rotation mechanism (not shown) to drive the screw member 11. In this case, to prevent the target workpiece 1 from deforming or collapsing due to the weight of the screw member 11, the guide length of the screw member 11 may be determined using the insertion angle, the mass of the screw member 11, the effective diameter, the length from the tip to the center of gravity of the screw member 11, the yield stress of the target workpiece 1, and the gravitational acceleration, and the position of the gripping jaws 35 may be adjusted based on the guide length.

[0072] Furthermore, when driving the screw 11 at an angle, if the gripping length of the gripping claws 35 to grip the screw 11 is not appropriate, the screw 11 cannot be held without deforming or collapsing the target member 1. Therefore, the gripping length of the gripping claws 35 may be designed based on the expected maximum angle of inclination when driving the screw 11, the guide length of the screw 11, and the length of the screw 11. By designing the gripping claws 35 in this way, the screw 11 can be driven with high precision without deforming or collapsing the target member 1 and while maintaining its aesthetic appearance.

[0073] Furthermore, the target material 1 to be driven by the driving device 10 is not limited to a layered mortar material. The target material may be, for example, a building board or wood.

[0074] 1...workpiece to be driven, 10...driving device, 11...screw member, 12...tool engagement groove (tool engagement portion), 13...rotary tool, 14...base block, 17...screw feed unit (screw feed portion), 18...screw holding unit (screw holding portion), 19...driver, 20...elevating device (advancing and retreating device), 24...cam block (holding release mechanism), 25...operating piece (holding release mechanism), 35...gripping claw, 37...biasing spring, 111...screw member, 40...female screw, 42...male screw

Claims

1. A device for driving a screw member, comprising: a screw feed unit that feeds a screw member having a tool engagement portion formed at one end in the axial direction to a position where the screw member is to be driven; a screw holding unit that holds the screw member fed from the screw feed unit in a fixed position; a driver that holds a tool engaged with the tool engagement portion and rotates the tool; and an advancing / retracting device that moves the driver forward and backward in the axial direction of the screw member, wherein the screw holding unit is equipped with a hold release mechanism that releases the driver's hold on the screw member when the driver comes closer than a predetermined distance to a material into which the screw member is to be driven.

2. A screw member driving device as described in claim 1, wherein the predetermined distance is a distance at which the screw member is driven to a specified depth into the target member.

3. A device for driving a screw member as described in claim 1, wherein the screw holding portion comprises: a plurality of gripping claws that can abut against the outer peripheral surface of the shank of the screw member; a biasing portion that biases the gripping claws in a direction pressing them against the outer peripheral surface of the shank; an operating piece that moves back and forth integrally with the driver; and a cam block that receives a pressing force from the operating piece and moves the gripping claws in a direction away from the outer peripheral surface of the shank when the driver approaches the object of driving more than a predetermined distance, and wherein the operating piece and the cam block constitute the hold release mechanism.

4. The screw driving device according to claim 1, wherein the retention release mechanism includes an adjustment mechanism that can change the predetermined distance.

5. A screw member driving device as described in claim 1, wherein the predetermined distance is determined according to the member to be driven.

6. A screw member driving device as described in claim 1, comprising a base block on which the advance / retract device and the driver are installed, and the screw feed unit is constituted by a cartridge that can be loaded with a large number of the screw members and is detachably attached to the base block.

7. A screw member driving device as described in claim 1, wherein the screw member has a female thread formed on one axial end surface and a male thread having a shape complementary to the female thread formed on the other axial end surface.

8. A screw member driving device as described in any one of claims 1 to 7, wherein the target material into which the screw member is driven is a mortar material shaped in a laminated state.

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