CA1113289A - Self-tapping screw - Google Patents
Self-tapping screwInfo
- Publication number
- CA1113289A CA1113289A CA308,227A CA308227A CA1113289A CA 1113289 A CA1113289 A CA 1113289A CA 308227 A CA308227 A CA 308227A CA 1113289 A CA1113289 A CA 1113289A
- Authority
- CA
- Canada
- Prior art keywords
- screw
- shank
- forming portion
- self
- blind
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000010079 rubber tapping Methods 0.000 title claims abstract description 47
- 238000005253 cladding Methods 0.000 claims abstract description 16
- 239000000463 material Substances 0.000 claims abstract description 15
- 239000002184 metal Substances 0.000 claims description 7
- 229910052751 metal Inorganic materials 0.000 claims description 7
- 239000004033 plastic Substances 0.000 claims description 7
- 229920003023 plastic Polymers 0.000 claims description 7
- 238000010438 heat treatment Methods 0.000 claims description 4
- 229910000831 Steel Inorganic materials 0.000 claims description 3
- 239000010959 steel Substances 0.000 claims description 3
- 238000009434 installation Methods 0.000 claims description 2
- 230000000875 corresponding effect Effects 0.000 claims 3
- 230000000149 penetrating effect Effects 0.000 claims 3
- 230000035515 penetration Effects 0.000 claims 1
- 238000005260 corrosion Methods 0.000 abstract description 11
- 230000007797 corrosion Effects 0.000 abstract description 9
- 230000033228 biological regulation Effects 0.000 description 4
- 239000003086 colorant Substances 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000011253 protective coating Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B35/00—Screw-bolts; Stay-bolts; Screw-threaded studs; Screws; Set screws
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B33/00—Features common to bolt and nut
- F16B33/008—Corrosion preventing means
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Joining Of Building Structures In Genera (AREA)
- Roof Covering Using Slabs Or Stiff Sheets (AREA)
- Connection Of Plates (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A self-tapping screw for fixing plates or other covering or cladding members to purlins, beams or similar supports. The screw-threaded shank portion is formed of material of sufficient hardness to permit self-tapping.
The head of the screw is a separate member in the form of a blind nut and is of a material which resists corrosion.
A self-tapping screw for fixing plates or other covering or cladding members to purlins, beams or similar supports. The screw-threaded shank portion is formed of material of sufficient hardness to permit self-tapping.
The head of the screw is a separate member in the form of a blind nut and is of a material which resists corrosion.
Description
i~3 32~J~
The present invention relates generally to the securing of plates or other covering or cladding members t to purlin beams or similar supports.
It is known for this securing function to be performed by means of fasteners or connectors which fit on to the purlins, beams or other supports and which have holes, the holes possibly being screw-threaded or associated with a nut for receiving screws or screw-threaded rods which pass through holes in the plates or other covering or cladding members~
However, it is also known for this purpose to use screws which are screwed directly into a hole provided in -the purlin beam, beam member or similar support, the screw at the same time forming the screw-threading in the hole, or even screws which are self-tapping and self-piercing and which themselves form the hole required in the beam or similar member, forming the screw-threading at the same time.
It will readily be seen that these screws must be made of a very hard material, and they are generally made of steel which has been sub~ected to treatment capable of ~; imparting to the screw and to its screw threads a degree of ~ hardness which is higher than that of the support.
`~ However, the regulations in force in the building industr~i, in respect of devices and members for securing `l ~ 25 covering or cladding plates, require such devices or members to have an anti-corrosion nature, at least in their part which is exposed to the exterior.
¦~ When the devices or members for securing covering ji or cladding plates are metal members, properties of this - 1 - .
., ~
:
,. . : ; . .
Z~
:
kind are produced by galvanisation.
However, providing protection on the securing devices or members by hot galvanisation~ which makes it possible to meet the above-mentioned regulations, cannot be employed on self-tapping screws or on self-tapping and self-piercing screws of the type mentioned above-~ because on the one hand the temperature required for producing this galvanisation protection, being of the order of 450C, nullifies the effect of the heat treatment which was pre-viously applied to the screw in order to ach~e the requireddegree of hardness, and because on the other hand iron dissolves into the zinc applied to form the protective coating, thus resulting in a composition which is devoid of the hardness properties which make it possible for the screw to h~ve a self-tapping function when it is screwed into the hole in the beam or other support.
Such self-tapping or self-piercing and self-tapping screws cannot therefore be used in this form for the use envisaged above.
Attempts have already been made to remedy this disadvantage, for example by in3ecting a head of plastics material around the head of the screw. However, this operation is burdensom~ and moreover stocking screws with heads of different colours in the different sizes required according to the use envisaged therefore becomes a very ma~or underta-king and represents an enormous amount of tied-up capital.
` It has also been proposed that a thin cap of plastics material be simply fitted to the screw, the cap being fitted on to the screw head by resilient deformation, ~ - 2 -:
`f~ "
to provide the screw with protection from corrosion. However, such a solu-tion has been found to be technically disastrous.
A primary object of the invention is therefore to provide a solu-tion to the problem which is thus encountered and to provide a self-tapping screw whose self-tapping portion is of the necessary degree of hardness while the screw portion which forms the screw head and which is exposed to the exterior complies with the prevailing regulations as regards its corrosion-resistant nature.
For this purpose, the invention is embodied in a self-tapping screw for securing plates or other covering or cladding members to purlins, beams or like supports, comprising a shank-forming portion, a screw thread provided on said shank-forming portion, said screw-thread having the degree of hardness required for forming a screw-thread in a hole of a purlin or beam, a blind-nut portion, said blind-nut portion being of material having anticorrosion characteristics, being separate from said shank-forming por-tion and having sufficient strength to transmit tightening torque to drive the screw, and a screw-thread provided in said blind-nut portion for fitting said blind-nut portion by screwing onto said shank-forming portion to installation to complete the self-tapping screw.
It is already known in this technical art to use threaded rods associated with a blind nut, in particular with fasteners or connectors for securing plates or other covering or cladding members. However, in this case, such fasteners or connectors are provided with a screw thread or a captive nut into which the threaded rod can be screwed, or else the fasteners or connectors have holes for receiving the threaded rod, which itself receives a normal nut, and the blind nut is fitted on to the threaded rod to provide for rotation thereof ` ..
:.,~.... . . :
. .
:: .
.:, : ' ' z~
for gripping the coverlng member. There is therefore no provision for a self-tapping function in this known use~
In the present case, the invention takes advantage of the means formed by the sub-division of an assembly for performing a fixing function by screwing, into a shank portion and a blind nut, so that, by adaptation of the nature of said components, one of which is of a sufficient degree of hardness to perform a self-tapping action in a purlin or beam by virtue of its screw thread, while the other component is of an anti-corrosion nature, said components perform different functions, for attaining a result which is also different, namely securing a covering or cladding plate directly, without fastener or connector, to a purlin, beam or similar support, by self-tapping of a hole in said beam or purlin.
The shank-forming portion of the self-tapping screw may have an end part of frusto-conical shape when it is intended simply to tap a screw thread in the wall of a hole which has previously been pierced in the purlin or beam~
However, in an alternative form, the shank-forming portion may also be provided with a pointed end, in which case the screw can perform both a self-piercing and a self-tapping operation.
In accordance with a possible embodiment, the portion formed by the blind nut may be screwed directly on to the rearward end of the shank of the screw, in which ca~e I ~ .
¦;the open end face of the blind nut acts directly to tighten ;-the covering member against the purlin or beam.
;~ In an alternative form, the shank-forming portion :
_ 4 _ .. ';~ `'~ ' , ' . " . .',. ' . -." ' ' ' ' .~ ,, ' ' ' . ~
3Z -~ 3 of the screw may be provided at its rearward end with a region forming a collar to provide a ~houlder whereby the covering member is gripped against the purlin or beam, the periphery of said collar having a screw thread for receiving S the blind nu t .
The screw may be screwed directly into the hole in the purlin or beam, performing its self-tapping function, by means of the blind nut after the blind nut has been fitted on to the rearward end of the shank-forming portion of the 1 screw. However, according to the invention, it is also possible for the rearward end of the shank-forming portion of the screw to be provided with means for rotating said shank-forming portion 50 that the shank-forming portion penetrates ; by a self-tapping action into the hole in the purlin or beam, the blind nut be~ng fitted subsequently by screwing on to said rearward end.
The above-mentioned means may comprise for example j ~ a slot in the shank of the screw~ or a recess, or any other configuration whereby the screw may be rotated.
The shank-forming portion of the self-tapping screw according to the invention is appropriately made of steel ~hich has been sub~ected to heat treatment capable of ;~ ~ imparting thereto the required hardness, in conventional manner. The blind nut may be made of any material capable of ~25 being anti-corrosive in nature, for example metal which has l~been subjected to a galvanisatlon treatment or plastics material. In the latter case, the self-tapping screw produced is distinguished from the known constructions because the exposed part is formed by the mechanically strong blind nut ~ .
.: . ,: :
which may itse~ form the retaining portion for retaining the covering member on the purlin or ~eam, and not simply by a thin cap of plastics material which is snap-fitted on to a screw head of a metal which may suffer corrosion.
The assembly according to the invention not only has the advantage of complying with the prevailing regula-tions, while making it possible to solve the technical problem set, because it comprises a self-tapping shank portion of sufficient hardness, while its exposed end portion is capable of resisting corrosion, but also the assembly according to the invention makes it possible to achieve savings in comparison with the prior art, in particular in the aspect of stocking, which is reduced very substantially as it is possible to stock on the one hand screws of different lengths~
in the manner normally required in this art~ and on the other hand blind nuts forming screw heads, of different colours, without any need to take into conslderation the length of the screws on which the blind nuts will be fitted.
~urther ob~ects and advantages of the invention will be apparent from the following description of preferred :
embodiments illustrated in the accompanying drawings.
Figure 1 is a diagrammatic view of one embodiment 1 1 of a self-tapping screw according to the invention.
Pigure 2 is a view similar to Pigure 1, howing an alternative embodiment.
The embodiment shown in Figure 1 corresponds to a self-tapping screw comprising a shank-forming portion 1 which is provided with a screw thread 2 and which at its forward end terminates in a region 3 of frusto-conical shape, with a flat end face. By virtue of its configuration this screw is .
,, " , . . .
, , :. , - . ~ : , -3~
intended to be introduced with a self-tapping action into a hole previously formed for example in a beam or purlin. The shank portion 1 of the self-tapping screw has been sub~ected to heat treatment so as to be very hard, in the usual manner, thus permitting the screw to cut a screw thread directly in the wall of the hole previously formed in the beam or purlin.
In accordance with the invention, the self-tapping screw is completed by a head 4 in the form of a blind nut, that is to say, the head is providad with an internal screw thread which, in the present case, is intended to be screwed on to the external screw thread 2 of the shank portion 1 of the self-tapping screw.
The blind nut may be made of a material which is treated so as to be corrosion-resistant, or of plastics material. The blind nut is of a polygonal external configu-ration, in a manner not shown in the drawing but known per se, and it is of sufficient mechanical strength to permit the shank portion 1 of the screw to be driven by means of a spanner or another tool, to form the necessary screw thread in the metal of the beam or purlin when the blind nut has been fitted by means of its screw thread 5 on to the screw thread 2 of the shank portion 1 of the screw and is turned by means of the above-mentioned tool.
A covering member is secured by means of the self-tapping screw 1 and 4 shown in Figure 1~ by introducing the shank portion 1 of the screw into the hole in the covering member and into the hole in the beam or purlin, and screwing the screw until the open end face 6 of the blind nut assumes a position in which it clamps the covering member against the beam or purlin, the shank portion 1 of the screw as indicated _ 7 -.
I ., , - . . . . .
z~
cutting its own screw thread in the wall of the hole in which it is engaged.
In the embodiment shown in Figure 2, the self-tapping screw also comprises a shank-forming portion 7 S which is provided with a screw thread ~ and that has been subjected to a treatment capable of imparting thereto the required degree of hardness. In the present case, the shank portion 7 however is provided with a pointed front end 9 so that the screw in question may be used, if desired, both as a self-piercing and self-tapping screw.
The shank-forming portion 7 of the screw is provided at its end remote from the pointed end 9 with a head-forming collar 10 which~ together with the shank portion 7~ forms a shoulder 11. The collar 10 is provided in the present case with a slot 12 for receiving a screwdriver. The slot 12 could be replaced for example, if desired, by a recess intended to receive a spanner for turning the screw. `;
The head 10 is also provided with a screw thread J. ~ 13 on lts periphery. Like the screw described above, the screw shown in ~igure 2 also comprises a portion 14 forming a blind nut, which is provided with an internal screw thread 15 which can co-operate by screwing with the screw thread 13 of the head 10. In this case also, the blind nut 14 comprises ~ a metal capable of resisting corrosion, or a hard plastics ¦~ 25 material, the blind nut 14 preferably being of polygonal f~ ou tline.
¦ To use this screw, the shank portion 7 is first engaged in the hole provided for receiving i* in the covering member, and then in the hole in the purlin or beam if the screw is used as a self-tapping screw~ or else the screw is - 8 _ .
. :. i . - .
: .
z~
forcibly engaged in the metal forming the purlin or beam if the screw has both a self-piercing and self-tapping action.
This insertion operation is continued until the head 10 of the shank portion 7 of the screw assumes a position in which it clamps the covering member against the beam or purlin by way of the shoulder 11, the screw having been rotated in the present case by means of the slot 12, by a screwdriver. The blind nut 14 which forms the corroslon-resistant member is then screwed on to the screw thread 13 of the head 10.
It will be readily understood from the foregoing ~ description that the self-tapping and corrosion-resistance ; functions have thus been separated, thereby solving the apparently contradictory problems set out hereinbefore, concerning the hardness required for the self-tapping portion lS and the corrosion-resistant nature of the exposed portion.
In addition, it will be seen that it is possible in this way largely to reduce the stock of self-tapping screws since it is possible to keep in stock, on the one hand, screw shanks of different lengths, to fulfil the needs which will ari~e, and on the other hand, blind nuts of different colours which can be fitted on to the screw shanks, to complete the fixing operation while being corrosion-resistant.
Modifications may be made in the above-described embodiments, in the range of technical equivalents, without thereby departing from the invention. Thus~ although the pitch of the screw thread of the blind nut and that of the head 10 are here equal to the pitch of the screw thread on the shank portion of the screw, it will be appreciated that a different pitch may also be employed, if desired. In addition~ although a self-piercing and self-tapping screw _ 9 --:. . , ~ - . - . .
The present invention relates generally to the securing of plates or other covering or cladding members t to purlin beams or similar supports.
It is known for this securing function to be performed by means of fasteners or connectors which fit on to the purlins, beams or other supports and which have holes, the holes possibly being screw-threaded or associated with a nut for receiving screws or screw-threaded rods which pass through holes in the plates or other covering or cladding members~
However, it is also known for this purpose to use screws which are screwed directly into a hole provided in -the purlin beam, beam member or similar support, the screw at the same time forming the screw-threading in the hole, or even screws which are self-tapping and self-piercing and which themselves form the hole required in the beam or similar member, forming the screw-threading at the same time.
It will readily be seen that these screws must be made of a very hard material, and they are generally made of steel which has been sub~ected to treatment capable of ~; imparting to the screw and to its screw threads a degree of ~ hardness which is higher than that of the support.
`~ However, the regulations in force in the building industr~i, in respect of devices and members for securing `l ~ 25 covering or cladding plates, require such devices or members to have an anti-corrosion nature, at least in their part which is exposed to the exterior.
¦~ When the devices or members for securing covering ji or cladding plates are metal members, properties of this - 1 - .
., ~
:
,. . : ; . .
Z~
:
kind are produced by galvanisation.
However, providing protection on the securing devices or members by hot galvanisation~ which makes it possible to meet the above-mentioned regulations, cannot be employed on self-tapping screws or on self-tapping and self-piercing screws of the type mentioned above-~ because on the one hand the temperature required for producing this galvanisation protection, being of the order of 450C, nullifies the effect of the heat treatment which was pre-viously applied to the screw in order to ach~e the requireddegree of hardness, and because on the other hand iron dissolves into the zinc applied to form the protective coating, thus resulting in a composition which is devoid of the hardness properties which make it possible for the screw to h~ve a self-tapping function when it is screwed into the hole in the beam or other support.
Such self-tapping or self-piercing and self-tapping screws cannot therefore be used in this form for the use envisaged above.
Attempts have already been made to remedy this disadvantage, for example by in3ecting a head of plastics material around the head of the screw. However, this operation is burdensom~ and moreover stocking screws with heads of different colours in the different sizes required according to the use envisaged therefore becomes a very ma~or underta-king and represents an enormous amount of tied-up capital.
` It has also been proposed that a thin cap of plastics material be simply fitted to the screw, the cap being fitted on to the screw head by resilient deformation, ~ - 2 -:
`f~ "
to provide the screw with protection from corrosion. However, such a solu-tion has been found to be technically disastrous.
A primary object of the invention is therefore to provide a solu-tion to the problem which is thus encountered and to provide a self-tapping screw whose self-tapping portion is of the necessary degree of hardness while the screw portion which forms the screw head and which is exposed to the exterior complies with the prevailing regulations as regards its corrosion-resistant nature.
For this purpose, the invention is embodied in a self-tapping screw for securing plates or other covering or cladding members to purlins, beams or like supports, comprising a shank-forming portion, a screw thread provided on said shank-forming portion, said screw-thread having the degree of hardness required for forming a screw-thread in a hole of a purlin or beam, a blind-nut portion, said blind-nut portion being of material having anticorrosion characteristics, being separate from said shank-forming por-tion and having sufficient strength to transmit tightening torque to drive the screw, and a screw-thread provided in said blind-nut portion for fitting said blind-nut portion by screwing onto said shank-forming portion to installation to complete the self-tapping screw.
It is already known in this technical art to use threaded rods associated with a blind nut, in particular with fasteners or connectors for securing plates or other covering or cladding members. However, in this case, such fasteners or connectors are provided with a screw thread or a captive nut into which the threaded rod can be screwed, or else the fasteners or connectors have holes for receiving the threaded rod, which itself receives a normal nut, and the blind nut is fitted on to the threaded rod to provide for rotation thereof ` ..
:.,~.... . . :
. .
:: .
.:, : ' ' z~
for gripping the coverlng member. There is therefore no provision for a self-tapping function in this known use~
In the present case, the invention takes advantage of the means formed by the sub-division of an assembly for performing a fixing function by screwing, into a shank portion and a blind nut, so that, by adaptation of the nature of said components, one of which is of a sufficient degree of hardness to perform a self-tapping action in a purlin or beam by virtue of its screw thread, while the other component is of an anti-corrosion nature, said components perform different functions, for attaining a result which is also different, namely securing a covering or cladding plate directly, without fastener or connector, to a purlin, beam or similar support, by self-tapping of a hole in said beam or purlin.
The shank-forming portion of the self-tapping screw may have an end part of frusto-conical shape when it is intended simply to tap a screw thread in the wall of a hole which has previously been pierced in the purlin or beam~
However, in an alternative form, the shank-forming portion may also be provided with a pointed end, in which case the screw can perform both a self-piercing and a self-tapping operation.
In accordance with a possible embodiment, the portion formed by the blind nut may be screwed directly on to the rearward end of the shank of the screw, in which ca~e I ~ .
¦;the open end face of the blind nut acts directly to tighten ;-the covering member against the purlin or beam.
;~ In an alternative form, the shank-forming portion :
_ 4 _ .. ';~ `'~ ' , ' . " . .',. ' . -." ' ' ' ' .~ ,, ' ' ' . ~
3Z -~ 3 of the screw may be provided at its rearward end with a region forming a collar to provide a ~houlder whereby the covering member is gripped against the purlin or beam, the periphery of said collar having a screw thread for receiving S the blind nu t .
The screw may be screwed directly into the hole in the purlin or beam, performing its self-tapping function, by means of the blind nut after the blind nut has been fitted on to the rearward end of the shank-forming portion of the 1 screw. However, according to the invention, it is also possible for the rearward end of the shank-forming portion of the screw to be provided with means for rotating said shank-forming portion 50 that the shank-forming portion penetrates ; by a self-tapping action into the hole in the purlin or beam, the blind nut be~ng fitted subsequently by screwing on to said rearward end.
The above-mentioned means may comprise for example j ~ a slot in the shank of the screw~ or a recess, or any other configuration whereby the screw may be rotated.
The shank-forming portion of the self-tapping screw according to the invention is appropriately made of steel ~hich has been sub~ected to heat treatment capable of ;~ ~ imparting thereto the required hardness, in conventional manner. The blind nut may be made of any material capable of ~25 being anti-corrosive in nature, for example metal which has l~been subjected to a galvanisatlon treatment or plastics material. In the latter case, the self-tapping screw produced is distinguished from the known constructions because the exposed part is formed by the mechanically strong blind nut ~ .
.: . ,: :
which may itse~ form the retaining portion for retaining the covering member on the purlin or ~eam, and not simply by a thin cap of plastics material which is snap-fitted on to a screw head of a metal which may suffer corrosion.
The assembly according to the invention not only has the advantage of complying with the prevailing regula-tions, while making it possible to solve the technical problem set, because it comprises a self-tapping shank portion of sufficient hardness, while its exposed end portion is capable of resisting corrosion, but also the assembly according to the invention makes it possible to achieve savings in comparison with the prior art, in particular in the aspect of stocking, which is reduced very substantially as it is possible to stock on the one hand screws of different lengths~
in the manner normally required in this art~ and on the other hand blind nuts forming screw heads, of different colours, without any need to take into conslderation the length of the screws on which the blind nuts will be fitted.
~urther ob~ects and advantages of the invention will be apparent from the following description of preferred :
embodiments illustrated in the accompanying drawings.
Figure 1 is a diagrammatic view of one embodiment 1 1 of a self-tapping screw according to the invention.
Pigure 2 is a view similar to Pigure 1, howing an alternative embodiment.
The embodiment shown in Figure 1 corresponds to a self-tapping screw comprising a shank-forming portion 1 which is provided with a screw thread 2 and which at its forward end terminates in a region 3 of frusto-conical shape, with a flat end face. By virtue of its configuration this screw is .
,, " , . . .
, , :. , - . ~ : , -3~
intended to be introduced with a self-tapping action into a hole previously formed for example in a beam or purlin. The shank portion 1 of the self-tapping screw has been sub~ected to heat treatment so as to be very hard, in the usual manner, thus permitting the screw to cut a screw thread directly in the wall of the hole previously formed in the beam or purlin.
In accordance with the invention, the self-tapping screw is completed by a head 4 in the form of a blind nut, that is to say, the head is providad with an internal screw thread which, in the present case, is intended to be screwed on to the external screw thread 2 of the shank portion 1 of the self-tapping screw.
The blind nut may be made of a material which is treated so as to be corrosion-resistant, or of plastics material. The blind nut is of a polygonal external configu-ration, in a manner not shown in the drawing but known per se, and it is of sufficient mechanical strength to permit the shank portion 1 of the screw to be driven by means of a spanner or another tool, to form the necessary screw thread in the metal of the beam or purlin when the blind nut has been fitted by means of its screw thread 5 on to the screw thread 2 of the shank portion 1 of the screw and is turned by means of the above-mentioned tool.
A covering member is secured by means of the self-tapping screw 1 and 4 shown in Figure 1~ by introducing the shank portion 1 of the screw into the hole in the covering member and into the hole in the beam or purlin, and screwing the screw until the open end face 6 of the blind nut assumes a position in which it clamps the covering member against the beam or purlin, the shank portion 1 of the screw as indicated _ 7 -.
I ., , - . . . . .
z~
cutting its own screw thread in the wall of the hole in which it is engaged.
In the embodiment shown in Figure 2, the self-tapping screw also comprises a shank-forming portion 7 S which is provided with a screw thread ~ and that has been subjected to a treatment capable of imparting thereto the required degree of hardness. In the present case, the shank portion 7 however is provided with a pointed front end 9 so that the screw in question may be used, if desired, both as a self-piercing and self-tapping screw.
The shank-forming portion 7 of the screw is provided at its end remote from the pointed end 9 with a head-forming collar 10 which~ together with the shank portion 7~ forms a shoulder 11. The collar 10 is provided in the present case with a slot 12 for receiving a screwdriver. The slot 12 could be replaced for example, if desired, by a recess intended to receive a spanner for turning the screw. `;
The head 10 is also provided with a screw thread J. ~ 13 on lts periphery. Like the screw described above, the screw shown in ~igure 2 also comprises a portion 14 forming a blind nut, which is provided with an internal screw thread 15 which can co-operate by screwing with the screw thread 13 of the head 10. In this case also, the blind nut 14 comprises ~ a metal capable of resisting corrosion, or a hard plastics ¦~ 25 material, the blind nut 14 preferably being of polygonal f~ ou tline.
¦ To use this screw, the shank portion 7 is first engaged in the hole provided for receiving i* in the covering member, and then in the hole in the purlin or beam if the screw is used as a self-tapping screw~ or else the screw is - 8 _ .
. :. i . - .
: .
z~
forcibly engaged in the metal forming the purlin or beam if the screw has both a self-piercing and self-tapping action.
This insertion operation is continued until the head 10 of the shank portion 7 of the screw assumes a position in which it clamps the covering member against the beam or purlin by way of the shoulder 11, the screw having been rotated in the present case by means of the slot 12, by a screwdriver. The blind nut 14 which forms the corroslon-resistant member is then screwed on to the screw thread 13 of the head 10.
It will be readily understood from the foregoing ~ description that the self-tapping and corrosion-resistance ; functions have thus been separated, thereby solving the apparently contradictory problems set out hereinbefore, concerning the hardness required for the self-tapping portion lS and the corrosion-resistant nature of the exposed portion.
In addition, it will be seen that it is possible in this way largely to reduce the stock of self-tapping screws since it is possible to keep in stock, on the one hand, screw shanks of different lengths, to fulfil the needs which will ari~e, and on the other hand, blind nuts of different colours which can be fitted on to the screw shanks, to complete the fixing operation while being corrosion-resistant.
Modifications may be made in the above-described embodiments, in the range of technical equivalents, without thereby departing from the invention. Thus~ although the pitch of the screw thread of the blind nut and that of the head 10 are here equal to the pitch of the screw thread on the shank portion of the screw, it will be appreciated that a different pitch may also be employed, if desired. In addition~ although a self-piercing and self-tapping screw _ 9 --:. . , ~ - . - . .
2~9 provided with a pointed end is illustrated and described, it will be appreciated that another terminal configuration capable of achieving the same result may be employed, for example the front end of the screw may be of a form similar to that of a drill in order to form a hole.
., ;~
., ;~
3,:~
~'`'`,``~ ' ' ~ - 10 _ "
~'`'`,``~ ' ' ~ - 10 _ "
Claims (8)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A self-tapping screw for securing plates or other covering or cladding members to purlins, beams or like supports, comprising a shank-forming portion, a screw thread provided on said shank-forming portion, said screw-thread having the degree of hardness required for forming a screw-thread in a hole of a purlin or beam, a blind-nut portion, said blind-nut portion being of a material having anticorrosion characteristics, being separate from said shank-forming portion and having sufficient strength to transmit tightening torque to drive the screw, and a screw-thread provided in said blind-nut portion for fitting said blind-nut portion by screwing onto said shank-forming portion prior to installation to complete the self-tapping screw.
2. A self-tapping screw intended to tap a screw thread in the wall of a hole provided in a purlin, beam or like support for securing a plate or other covering or cladding member to said purlin, beam or like support ac-cording to claim 1 wherein said shank-forming portion comprises an end part of frusto-conical shape.
3. A self-tapping screw intended to be used as a self-piercing screw for securing plates or other covering or cladding members to perlins, beams or like supports according to claim 1 wherein said shank-forming portion comprises a hard pointed end for piercing said perlin, beam or like support.
4.- A self-tapping screw for securing plates or other covering or cladding members to purlins, beams or like supports according to claim 1, wherein said screw thread of said shank-forming portion extends on the whole length of said shank-forming portion and said screw-thread provided in said blind-nut portion has a pitch corresponding to said screw thread of said shank-forming portion and is screwable on said shank-forming portion.
5.- A self-tapping screw for securing plates or other covering or cladding members to purlins, beams or like supports according to claim 1, wherein said shank-forming portion comprises a forward end for penetrating the purlin, beam or like support and a rear end, and said screw thread provided on said shank-forming portion comprises a first zone extending over the major portion of the length of said shank-forming portion from its forward end and having a first pitch, and a second zone extending on the remaining portion of the length of said shank-forming portion and having a second pitch, different from said first pitch, and said screw thread provided in said blind-nut portion has a pitch corres-ponding to said second pitch of said shank-forming portion.
6.- A self-tapping screw for securing plates or other covering or cladding members to purlins, beams or like supports according to claim 1, wherein said shank-forming portion comprises a forward end for penetrating said purlin, beam or like support and a rear end, and a head is provided at said rear end of said shank-forming portion, a screw-thread being present at the periphery of said head, said screw thread of said blind-nut portion corresponding to said screw thread on said head of said shank-forming portion.
7. A self-tapping screw for securing plates or other covering or cladding members to purlins, beams or like supports according to claim 1, wherein said shank-forming portion comprises a forward end for penetrating said purlin, beam or like support and a rear end, and comprising a collar or like profile at said rear end for limiting the penetration of said shank-forming portion into said purlin, beam or like support.
8. A self-tapping screw for securing plates or other covering or cladding members to purlins, beams or like supports according to claim 1, wherein said shank-forming portion is made of steel having been subjected to a heat treatment capable of imparting thereto a high hardness and said blind-nut portion is made of a material of the group comprising a metal which has been subjected to a galvanisation or like treatment and a plastic material.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR77-28432 | 1977-09-21 | ||
| FR7728432A FR2404141A1 (en) | 1977-09-21 | 1977-09-21 | SELF-TAPPING SCREWS FOR FIXING COVERING OR SIDING ELEMENTS |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1113289A true CA1113289A (en) | 1981-12-01 |
Family
ID=9195607
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA308,227A Expired CA1113289A (en) | 1977-09-21 | 1978-07-26 | Self-tapping screw |
Country Status (5)
| Country | Link |
|---|---|
| BE (1) | BE868511A (en) |
| CA (1) | CA1113289A (en) |
| CH (1) | CH623638A5 (en) |
| DE (1) | DE2836846A1 (en) |
| FR (1) | FR2404141A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110397654A (en) * | 2018-04-25 | 2019-11-01 | 赛峰起落架系统英国有限公司 | Aircraft assembly |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH684706A5 (en) * | 1989-11-13 | 1994-11-30 | Isolink Ltd | Fastener. |
| CA2252173A1 (en) * | 1998-10-27 | 2000-04-27 | Thomas W. Mcsherry | Hook and anchor assembly |
| FR2852643B1 (en) * | 2003-03-20 | 2006-11-17 | SCREW AND NUT FIXING BOLT, IN PARTICULAR FOR ATTACHING PLATES OR COVERING OR SADDING ELEMENTS | |
| DE202006017711U1 (en) * | 2006-11-14 | 2007-02-08 | Adolf Würth GmbH & Co. KG | Attachment arrangement for timber constructions, has threaded rod with wooden thread around and over entire length |
| DE102007038976A1 (en) * | 2007-08-17 | 2009-03-12 | Ludwig Hettich & Co. | Screw anchor for fixings in concrete and masonry |
| CN105351324A (en) * | 2015-10-30 | 2016-02-24 | 无锡市东赫金属制品有限公司 | Dismounting and mounting type bolt |
| CN107524680A (en) * | 2017-10-19 | 2017-12-29 | 苏州华丰不锈钢紧固件有限公司 | Hex(agonal)screw simple in construction |
| DE102020210921A1 (en) * | 2020-08-28 | 2022-03-03 | Toge Dübel Gmbh & Co. Kg | Method for setting an anchor element and arrangement with such an anchor element in a material |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR494921A (en) * | 1918-01-15 | 1919-09-24 | Gabriel Robergel | Bolt manufacturing process |
| US1450583A (en) * | 1921-01-28 | 1923-04-03 | Ferry Thomas | Fastening device |
| FR606122A (en) * | 1924-11-15 | 1926-06-08 | Improvements made to mechanical parts comprising, on a rod, an open part, such as in particular bolts | |
| US1988813A (en) * | 1934-07-11 | 1935-01-22 | Oscar J Seguin | Lug bolt and cap for same |
| US3134290A (en) * | 1962-08-23 | 1964-05-26 | Robertson Co H H | Corrosion resistant metal screw with a plastic head |
| FR2260019A1 (en) * | 1974-02-01 | 1975-08-29 | Roblin Pierre | Rivet simulating fixing piece - has threaded stud fitting in tapped bore in a head |
-
1977
- 1977-09-21 FR FR7728432A patent/FR2404141A1/en active Granted
-
1978
- 1978-06-27 BE BE188885A patent/BE868511A/en not_active IP Right Cessation
- 1978-07-26 CA CA308,227A patent/CA1113289A/en not_active Expired
- 1978-08-21 CH CH882878A patent/CH623638A5/en not_active IP Right Cessation
- 1978-08-23 DE DE19782836846 patent/DE2836846A1/en not_active Withdrawn
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110397654A (en) * | 2018-04-25 | 2019-11-01 | 赛峰起落架系统英国有限公司 | Aircraft assembly |
Also Published As
| Publication number | Publication date |
|---|---|
| BE868511A (en) | 1978-10-16 |
| FR2404141A1 (en) | 1979-04-20 |
| DE2836846A1 (en) | 1979-03-29 |
| CH623638A5 (en) | 1981-06-15 |
| FR2404141B1 (en) | 1982-11-26 |
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| Date | Code | Title | Description |
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| MKEX | Expiry |