JP2011002089A - Dropping-out prevention tool of screw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dropping-out prevention tool capable of preventing dropping out of a screw by attaching from one surface of a fastening member.SOLUTION: The dropping-out prevention tool 4 has an insertion section 41, a flange section 43 wherein its diameter is enlarged rather than the insertion section 41, and a through-hole 44 penetrating these sections in the axial direction. A projection 45 projecting from a flat side face section 41b to its outer peripheral side is formed on the insertion section 41, and it is deformable so as to shorten its separating distance to the flat side face section 41b. The prevention tool 4 is divided into a first section 50 and a second section 60 by first and second crossed sections 51, 61 extending in the axial direction. A press-fitted projecting section 52 projecting toward the second section 60 and a fitted projecting section 53 located at a lower face 4b side rather than the press-fitted projecting section are formed on the first crossed section 51 of the first section 50. A press-fitted recessed section 62 capable of press-fitting to the press-fitted projecting section 52 and a fitted recessed section 63 capable of fitting to the fitted projecting section 53 are formed on the second crossed section 61 of the second section 60.

Description

  The present invention relates to a drop-off prevention tool that prevents a screw from dropping from a mounting opening formed in a fastening member.

  2. Description of the Related Art Conventionally, a screw drop prevention tool that is attached to an attachment opening of a fastening member and holds a screw is known. For example, according to Japanese Patent Application Laid-Open No. 11-336732 (Patent Document 1), two attachment pieces are continuous with continuous pieces, and openings that are larger than the diameters of screw portions of the screws are respectively formed in these continuous pieces. ing. A claw portion that can be elastically deformed and can lock the outer peripheral portion of the screw portion is formed on the inner peripheral side of the opening. The fastening member has a screw mounting opening, one mounting piece is positioned on the surface of the fastening member, the other mounting piece is positioned on the back surface, and the opening of these mounting pieces and the mounting opening of the fastening member Install so that and match. The screw is attached from the front surface side to the back surface side of the fastening member through the opening of the attachment piece and the attachment opening. Such a screw is locked by a claw portion formed in the opening. Therefore, it is possible to prevent the screw from dropping from the mounting opening of the fastening member.

JP-A-11-337732 (H11-336732A)

Since the two attachment pieces are continuous by the continuous piece, depending on the size of the fastening member, the length of the continuous piece is insufficient, and the attachment piece cannot be attached to the front and back surfaces so as to match the attachment opening. .
Also, in order to attach the other attachment piece to the back surface while positioning one attachment piece on the front surface, you have to turn your hand to the back surface side. Can not be installed. In addition, it may be narrow because other devices are installed on the back surface, and in this case, it may not be possible to attach it because the hand is not in the vicinity of the attachment opening.

  The present invention provides a screw fall-off prevention tool that can solve the above-described problems by being attached from one surface of a fastening member.

  The present invention provides a screw including a screw head positioned in the axial direction, a screw portion in which a screw thread is formed, and a screw neck positioned between the screw head and the screw portion and having a diameter smaller than these. It is related with the improvement of the screw fall-off prevention tool which makes a fastening member hold | maintain.

  The present invention provides the screw drop prevention device, wherein the insertion portion has a smaller diameter than the mounting opening formed in the fastening member, and has a diameter larger than the mounting opening and extends from the insertion portion to the outer peripheral side and is axially oriented. A flange portion located on one end side, a protruding portion protruding to the outer peripheral side of the insertion portion, a through-hole penetrating the insertion portion and the inside of the flange portion in the axial direction, and the insertion along the axial direction A section that bisects the part into a first part and a second part, and the through hole has a large diameter part having a larger diameter than the screw part and a diameter larger than the screw neck part A small diameter portion having a smaller diameter than the screw portion, and the first portion and the second portion are engaged with each other by an engagement mechanism.

  As one of preferred embodiments of the present invention, the engagement mechanism is formed in a cross-section of the first portion and is formed in a cross-section of the second portion and a press-fit convex portion protruding toward the cross-section of the second portion. A press-fit concave portion capable of press-fitting the press-fit convex portion.

  As another preferred embodiment, the first portion and the second portion are rotatably connected by a connecting portion.

  As another preferred embodiment, the protrusion has flexibility, is formed on each of the first and second portions, and is spaced apart by 180 ° in the circumferential direction of the insertion portion. A proximal end joined to a portion and a distal end extending in the axial direction from the proximal end portion and spaced from the insertion portion, and a separation dimension between the proximal ends is made smaller than a diameter of the mounting opening. The distance between the tips is larger than the diameter of the mounting opening.

  As another preferred embodiment, a plurality of a pair of the press-fitting convex portions and the press-fitting concave portions are formed, and are formed on the object with the through hole interposed therebetween.

  As another preferred embodiment, the engagement mechanism is formed in a cross section of one of the first part and the second part and has a fitting convex part having a projection dimension shorter than the press-fitting convex part, A fitting recess that is formed on the other cross section of the first part and the second part and that can be fitted into the fitting protrusion; It is located closer to the connecting part than the press-fitting convex part and the press-fitting concave part.

  As another preferred embodiment, a tapered portion whose diameter is increased toward the flange portion is formed between the insertion portion and the flange portion.

  The screw drop prevention tool according to the present invention has an insertion portion having a smaller diameter than the mounting opening into which the screw is inserted, and the insertion portion can be divided into a first portion and a second portion by a cross section extending in the axial direction. Thus, by disposing the screws between the first portion and the second portion in a state where these are divided, the screws can be attached to the drop-off prevention device in advance. The drop-off prevention tool with the screw attached can be attached from one surface of the fastening member by inserting it into the attachment opening. Therefore, the drop-off prevention tool can be attached regardless of the size of the fastening member, and the screw can be prevented from falling off when the fastening member is removed.

The outline figure of a storage body and a cover panel. II partial enlarged view of FIG. The perspective view of a screw fall-off prevention tool. The top view of a screw drop-off prevention tool. VV sectional view taken on the line of FIG. The side view of FIG. VII-VII line sectional drawing of FIG. VIII-VIII sectional view taken on the line of FIG. Explanatory drawing when a press-fit convex part is fitted in the press-fit concave part. Explanatory drawing of a screw and a screw fall-off prevention tool.

1 to 10 show an embodiment of the present invention, and an example of a screw drop prevention tool when a cover is screwed to a main body is shown as an example.
1 is a schematic diagram of a storage body 2 and a cover panel 3 screwed by a screw 1, FIG. 2 is an enlarged view of a portion II in FIG. 1, FIG. 3 is a perspective view of a screw drop prevention device, and FIG. FIG. 5 is a sectional view taken along line VV in FIG. 4, FIG. 6 is a side view of FIG. 4, FIG. 7 is a sectional view taken along line VII-VII in FIG. FIG. 9 is an explanatory diagram when the press-fitting convex portion is fitted into the press-fitting concave portion, and FIG. 10 is an explanatory diagram of a screw and a screw drop prevention tool.

  As shown in FIG. 1, when the storage main body 2 that stores the server computer and the like and the cover panel 3 that covers the opening of the main body 2 are fastened with screws 1, the cover panel 3 includes a screw drop prevention tool. 4 is attached. The cover panel 3 that is a fastening member has a U-shaped periphery that is bent in order to maintain its strength. That is, the cover panel 3 includes a main body portion 31, a bent portion 32 that is bent substantially opposite to the main body portion 31, and a spacer portion 33 that holds the main body portion 31 and the bent portion 32 at regular intervals. Including. Such a cover panel 3 can be formed of steel having a thickness of about 2 mm, for example. An attachment opening 34 is formed in the main body portion 31, an attachment opening 35 is formed in the bent portion 32, and the screw 1 is inserted from the attachment opening 34 toward the attachment opening 35.

  A screw hole 21 is formed on the contact side of the storage body 2 on the cover panel 3. The screw hole 21 is formed coaxially with the mounting openings 34 and 35 of the cover panel 3, and the screw 1 is screwed into the screw hole 21, whereby the cover panel 3 is fastened to the storage body 2.

  As shown in FIG. 2, the screw 1 includes a screw head 11, a screw part 13 in which a screw thread is formed, and a screw neck part 12 positioned therebetween. The diameter of the screw head 11 is about 9.4 mm. The screw neck 12 has a diameter of about 2.5 mm and an axial length of about 15 mm. The screw portion 13 has a diameter of about 4 mm and an axial length of about 20 mm. As described above, the screw neck portion 12 is made smaller than the diameters of the screw head portion 11 and the screw portion 13. The screw tip at the axial end portion of the screw portion 13 forms a sharp portion 14 that is inclined so that its diameter decreases toward the end portion.

  As shown in FIGS. 2 and 3, the prevention device 4 has an insertion portion 41 having an axial direction that is the same as the axis of the screw 1 when the screw is mounted, and a diameter that can be inserted into the mounting opening 34. The taper portion 42 is adjacent to the axial direction of the taper portion 42 and is inclined so as to increase the diameter thereof, and the flange portion 43 is adjacent to the axial direction of the taper portion 42 and further increased in diameter thereof. The insertion portion 41 has a pair of arc portions 41a whose cross section is arcuate and a flat side surface portion 41b. Each of the taper portion 42 and the flange portion 43 has an annular circle having a center on the same axis. A through hole 44 is formed in the axial center of the insertion portion 41, the taper portion 42, and the flange portion 43 so as to penetrate them in the axial direction.

The pair of arc portions 41a are arranged approximately 180 ° apart from each other in the transverse direction of the insertion portion 41, and the dimension from one arc portion 41a to the other arc portion 41a is approximately 9.5 mm. The dimension from one flat side surface part 4b to the other flat side surface part 4b is further smaller than the dimension of the arc part 41a. The flange portion 43 is larger in diameter than the mounting opening 34 and has a diameter of about 13 mm. The taper portion 42 is inclined so as to increase its diameter from the insertion portion 41 toward the flange portion 43, and has a diameter of about 10 mm when the diameter on the flange portion 43 side is the largest. The diameter of the attachment opening 34 formed in the cover panel 3 is about 10 mm, and the insertion portion 41 can be inserted into the attachment opening 34, but the taper portion 42 is fitted with almost no gap. When the insertion portion 41 is thus inserted into the mounting opening 34, the flange portion 43 is brought into contact with the main body portion 31 of the cover panel 3.
The preventer 4 as described above has an upper surface 4 a and a lower surface 4 b that face each other in the axial direction, the upper surface 4 a is formed by the flange portion 43, and the lower surface 4 b is formed by the insertion portion 41.

  The insertion portion 41 is formed with a protruding portion 45 that protrudes from the flat side surface portion 41b to the outer peripheral side. The projecting portion 45 has a base end 45a continuous with the insertion portion 41 on the lower surface 4b, a distal end 45b extending substantially in the axial direction toward the upper surface 4a side, and spaced apart from the flat side surface portion 41b to the outside in the axial direction. The protrusions 45 are formed at two locations that are separated from each other by about 180 degrees in the circumferential direction of the insertion portion 41. The projecting portion 45 has flexibility and can be deformed so as to reduce the separation distance with respect to the flat side surface portion 41b. Further, these separation distances on the base end 45 a side are smaller than the diameter of the attachment opening 34, and these separation distances on the distal end 45 b side are larger than the diameter of the attachment opening 34. Therefore, when the preventer 4 is to be inserted into the attachment opening 34, the diameter of both the protrusion 45 and the insertion part 41 is smaller than that of the attachment opening 34 on the lower surface 4b and can be easily inserted. Since the separation distance of the protrusion 45 increases toward the upper surface 4a, the attachment opening 34 is slid while being bent so that the separation distance of the protrusion 45 is reduced. When the tip 45b exceeds the attachment opening 34, the protrusion 45 returns to the original state, and the distance between them increases, thereby preventing the prevention tool 4 from coming out of the attachment opening 34.

  The through hole 44 has a small diameter portion 46 having a diameter of about 3 mm and a large diameter portion 47 having a diameter of about 4.4 mm. The large-diameter portion 47 is located on the lower surface 4 b side with respect to the small-diameter portion 46 and is formed to be larger than the diameter of the screw thread forming portion 13. The small diameter portion 46 is formed to be larger than the screw neck portion 12 and smaller in diameter than the screw thread forming portion 13. In the screw 1, the screw neck 12 is held by the small diameter portion 46 of the prevention tool 4, the screw neck 13 is protruded in the axial direction from the lower surface 4 b of the prevention tool 4, and the screw head 11 is the upper surface of the prevention tool 4. It is projected and held in the axial direction from 4a.

  As shown in FIG. 3, the preventer 4 as described above is divided into a first portion 50 and a second portion 60 by first and second cross sections 51 and 61 extending in the axial direction. The 1st part 50 and the 2nd part 60 are connected by the connection part 70 in the lower surface 4b. The connection part 70 has flexibility and can hold | maintain the 1st part 50 and the 2nd part 60 so that rotation is possible. A pair of connecting portions 70 are formed on the target in the axial direction via the through holes 44.

  4 to 6 are views showing a state in which the first portion 50 and the second portion 60 of the prevention device 4 are rotated by about 180 ° from the state of FIG. 3, and the prevention device 4 of FIG. It is a figure of the state which rotated the 2nd part 60 about 60 degrees. As shown in the figure, one end 71 of the connecting portion 70 is joined to the lower surface 4b of the first portion 50, and the other end 72 is joined to the lower surface 4b of the second portion 60, and these are connected to each other. A groove 73 is formed between the one end 71 and the other end 72 of the connecting portion 70, and the connecting portion 70 is bent through the groove 73 so that the first portion 50 and the second portion 60 rotate. ing.

The first cross section 51 of the first portion 50 is formed with a press-fit convex portion 52 that protrudes toward the second portion 60 and a fitting convex portion 53 that is positioned on the lower surface 4b side. The press-fit convex portions 52 are formed symmetrically at two locations with the small diameter portion 46 interposed therebetween, and the fitting convex portions 53 are formed symmetrically at two locations with the large diameter portion 47 interposed therebetween.
In the second cross section 61 of the second portion 60, two press-fit recesses 62 that can be press-fitted into the press-fit convex part 52 are formed, and two fitting recesses 63 that can be fitted into the fitting convex part 53 are formed. .

The press-fit convex portion 52 has a length dimension t1 from the base portion 52a to the tip portion 52b of about 1.5 mm, and a diameter at the base portion 52a of about 1.2 mm. Moreover, as shown in FIG. 7, the convex part peripheral surface 54 inclines so that the diameter may become small toward the front-end | tip, and the inclination | tilt angle (theta) 1 is about 3 degrees. The inclination angle θ <b> 1 is an angle of the convex portion peripheral surface 54 with respect to the virtual axis center line 55 of the press-fit convex portion 52.
The press-fit recess 62 has a length dimension t2 from the base 62a to the bottom 62b of about 1.8 mm and a diameter of the base 62a of about 1.3 mm. Further, as shown in FIG. 8, the concave peripheral surface 64 is inclined so as to reduce its diameter toward the bottom 62b, and the inclination angle θ2 is about 7 °. The inclination angle θ <b> 2 is an angle of the recess peripheral surface 64 with respect to the virtual axis center line 65 of the press-fit recess 62.

  As shown in FIG. 9, by making the press-fit convex portion 52 and the press-fit concave portion 62 have the dimensional relationship as described above, the convex portion peripheral surface 54 comes into contact with the concave portion peripheral surface 64 and the concave portion peripheral surface 64 is pressed. However, the press-fit convex portion 52 can be fitted into the press-fit concave portion 62, and the press-fit convex portion 52 can be press-fit into the press-fit concave portion 62. In FIG. 9, the convex peripheral surface 54 is described so as to protrude from the concave peripheral surface 64 so that the dimensional relationship between the press convex convex portion 52 and the press concave portion 62 is clarified. The peripheral surfaces come into contact with each other while being pressed.

  Similarly, as shown in FIG. 6, the fitting convex portion 53 has a length dimension t3 from the base portion 53a to the tip portion 53b of about 1.0 mm, and a diameter at the base portion 53a of about 1.0 mm. The convex portion peripheral surface is inclined so as to reduce its diameter toward the tip, and the inclination angle θ3 is about 3 °. The fitting recess 63 has a length t4 from the base 63a to the bottom 63b of about 1.2 mm and a diameter of the base 63a of about 1.1 mm. The circumferential surface of the recess is inclined so as to reduce its diameter toward the bottom 63b, and the inclination angle θ4 is about 9 °. By making the fitting convex part 53 and the fitting concave part 63 into such a dimensional relationship, these can be fitted. However, these are not press-fitted, but have a function as a fitting guide between the press-fitting convex part 52 and the press-fitting concave part 62.

  In the preventer 4 as described above, the first portion 50 and the second portion 60 are rotated as shown in FIG. 10, and the screw 1 is inserted into the through hole 44 in an open state. However, in the state of FIG. 4 in which the first portion 50 and the second portion 60 are rotated by about 180 °, the separation dimension t5 of the lower surface 4b forming the through hole 44 is about 2 mm, which is larger than the diameter of the screw portion 13. It is getting smaller. Therefore, when the screw 1 is inserted, the first and second cross sections 51 and 61 of the first portion 50 and the second portion 60 are rotated, and the state shown in FIG. . Thus, by rotating the 1st part 50 and the 2nd part 60, the separation dimension t5 in the lower surface 4b can be expanded, and the screw part 13 can be inserted.

  When the screw 1 is inserted into the preventer 4, the press-fit convex portion 52 and the fitting convex portion 53 of the first portion 50 are fitted into the press-fit concave portion 62 and the fitting concave portion 63 of the second portion 60, respectively. The fitting convex portion 53 and the fitting concave portion 63 are fitted before the press-fit convex portion 52 and the press-fit concave portion 62, and function as a guide for aligning the fitting between the press-fit convex portion 52 and the press-fit concave portion 62. To do. The press-fit convex portion 52 is press-fitted into the press-fit concave portion 62 so that the first portion 50 and the second portion 60 are engaged. At this time, the screw head 11 is positioned so as to protrude outward in the axial direction from the flange portion 43, and the screw neck portion 12 is supported by the small diameter portion 46 of the through hole 44.

  The screw 1 held by the prevention tool 4 as described above is attached to the cover panel 3 by pushing the insertion portion 41 of the prevention tool 4 into the attachment opening 34 of the cover panel 3. Since the diameter of the insertion portion 41 is smaller than that of the attachment opening 34, the lower surface 4 b of the prevention tool 4 can be easily inserted into the cover panel 3. When the prevention tool 4 is pushed further into the back, as described above, the protrusion 45 slides on the mounting opening 34 while being bent. Then, the tapered portion 42 comes into contact with the mounting opening 34. Since the diameter of the tapered portion 42 on the flange 43 side is substantially the same as that of the mounting opening 34, the prevention tool 4 is inserted into the mounting opening 34 without a gap. Further, since the diameters of the taper portion 42 and the mounting opening 34 are substantially the same, the engagement between the first portion 50 and the second portion 60 can be maintained on the inner periphery of the mounting opening 34, and these are the first and first portions. It is possible to prevent the two cross sections 51 and 61 from being separated.

  The preventer 4 that has been pushed into the mounting opening 34 has its tapered portion 42 abutted against the main body portion 31 of the cover panel 3 and is not pushed further. At this time, the large-diameter portion 47 passes through the mounting opening 35 of the cover panel 3, is brought into contact with the screw hole 21 of the storage body 2, and the cover panel 3 is screwed into the storage body 2 by the rotation of the screw 1. When trying to position the screw 1 in the screw hole 21, misalignment or the like may occur. However, since the pointed portion 14 is formed at the screw tip of the screw 1, the pointed portion 14 uses the screw hole 21. It is possible to find the position of the object by simply contacting it.

  When removing the cover panel 3 from the storage body 2, the screw 1 is removed from the screw hole 21. After the screw part 13 is removed from the screw hole 21, the screw neck part 12 of the screw 1 slides through the through hole 44. It becomes possible. However, since the diameter of the screw portion 13 is larger than that of the small diameter portion 46, the screw 1 does not come off from the preventer 4. The preventer 4 does not come off the mounting opening 34 because the tapered portion 42 contacts the mounting opening 34 without a gap and the protrusion 45 is formed. Therefore, the screw 1 does not fall off from the cover panel 3 even after the screwing with the storage body 2 is released, and the problem due to the screw 1 dropping off can be solved.

  In this embodiment, the press-fit convex portion 52, the press-fit concave portion 62, the fitting convex portion 53, and the fitting concave portion 63 are used as the engagement mechanism, but the present invention is not limited to these. That is, a plurality of other concavo-convex portions to be press-fitted may be formed, and the press-fitting is not necessarily press-fitted. However, in order to securely engage the first portion 50 and the second portion 60 and to make it difficult to undo this engagement, it is desirable that at least a pair of concave and convex portions to be press-fitted be formed. Since the fitting uneven part functions as a guide for the press-fitting uneven part, the fitting uneven part is not necessarily press-fitted and is not an essential component.

1 Screw 3 Cover panel (fastening member)
4 Screw drop prevention tool 11 Screw head 12 Screw neck portion 13 Screw portion 34 Mounting opening 41 Insertion portion 42 Taper portion 43 Flange portion 44 Through hole 45 Projection portion 45a Base end 45b Tip end 46 Small diameter portion 47 Large diameter portion 50 First portion 51 First section 52 Press-fit convex part (engagement mechanism)
53 Fitting convex part (engagement mechanism)
60 2nd part 61 2nd cross section 62 Press-fit recessed part (engagement mechanism)
63 Fitting recess (engagement mechanism)
70 connecting part

Claims (7)

A screw including a screw head positioned in the axial direction, a screw portion formed with a screw thread, and a screw neck positioned between the screw head and the screw portion and smaller in diameter than the screw head is used as a fastening member. In the screw drop prevention tool to be held,
An insertion portion having a diameter smaller than the mounting opening formed in the fastening member, a flange portion having a diameter larger than the mounting opening and extending from the insertion portion to the outer peripheral side and positioned on one axial end side; and the insertion A projecting portion projecting to the outer peripheral side of the portion, a through hole penetrating the inside of the insertion portion and the flange portion in the axial direction, and the insertion portion along the axial direction into a first portion and a second portion A bisecting cross section, and
The through hole includes a large diameter portion having a diameter larger than the screw portion, and a small diameter portion having a diameter larger than the screw neck portion and a diameter smaller than the screw portion,
The screw drop prevention tool, wherein the first part and the second part are engaged with each other by an engagement mechanism.   The engagement mechanism includes a press-fit convex portion that is formed in a cross section of the first portion and protrudes toward a cross section of the second portion, and a press-fit concave portion that is formed in a cross section of the second portion and can press-fit the press-fit convex portion. The screw fall-off prevention tool of Claim 1 containing these.   The screw drop prevention tool according to claim 1 or 2, wherein the first part and the second part are rotatably connected by a connecting part. The protrusion has flexibility, is formed on each of the first and second portions, and is spaced apart by 180 ° in the circumferential direction of the insertion portion, and a proximal end joined to the insertion portion, A distal end extending in the axial direction from the proximal end portion and spaced from the insertion portion,
4. The screw drop-off according to claim 1, wherein a separation dimension between the base ends is made smaller than a diameter of the attachment opening, and a separation dimension between the tip ends is made larger than a diameter of the attachment opening. Prevention tool.   The screw drop prevention tool according to any one of claims 1 to 4, wherein a plurality of the pair of press-fitting protrusions and press-fitting depressions are formed on a target with the through hole being interposed therebetween. The engagement mechanism is formed on a cross section of one of the first part and the second part, and has a fitting convex part having a projection dimension shorter than the press-fitting convex part, and the first part and the second part. It is formed in any one of the other cross sections, and further includes a fitting recess that can be fitted into the fitting projection,
The screw drop prevention tool according to any one of claims 2 to 5, wherein the fitting convex portion and the fitting concave portion are located closer to the connecting portion than the press fitting convex portion and the press fitting concave portion.   The screw drop-off prevention tool according to any one of claims 1 to 6, wherein a tapered portion whose diameter is increased toward the flange portion is formed between the insertion portion and the flange portion.

Images