EP0279675B1 - Insert assembly for use in a concrete structure - Google Patents

Insert assembly for use in a concrete structure Download PDF

Info

Publication number
EP0279675B1
EP0279675B1 EP88301377A EP88301377A EP0279675B1 EP 0279675 B1 EP0279675 B1 EP 0279675B1 EP 88301377 A EP88301377 A EP 88301377A EP 88301377 A EP88301377 A EP 88301377A EP 0279675 B1 EP0279675 B1 EP 0279675B1
Authority
EP
European Patent Office
Prior art keywords
insert
insert member
intermediate portion
tapered
assembly according
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 - Lifetime
Application number
EP88301377A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0279675A1 (en
Inventor
Hiroyuki Arai
Ichiro Miyahashi
Saburo Tomisawa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ishikawajima Construction Materials Co Ltd
Original Assignee
Ishikawajima Construction Materials Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Ishikawajima Construction Materials Co Ltd filed Critical Ishikawajima Construction Materials Co Ltd
Publication of EP0279675A1 publication Critical patent/EP0279675A1/en
Application granted granted Critical
Publication of EP0279675B1 publication Critical patent/EP0279675B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
    • E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
    • E04B1/38—Connections for building structures in general
    • E04B1/388—Separate connecting elements
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
    • E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
    • E04B1/38—Connections for building structures in general
    • E04B1/41—Connecting devices specially adapted for embedding in concrete or masonry
    • E04B1/4114—Elements with sockets
    • E04B1/4121—Elements with sockets with internal threads or non-adjustable captive nuts

Definitions

  • This invention relates to an improvement in an insert assembly which is used for mounting or securing various appliances or equipments onto a concrete surface.
  • an insert member which is threadedly matable with a bolt member, is embedded within the concrete structure in order to mount various equipments onto the concrete surface.
  • This kind of insert member is generally made of a metal such as steel and the like, and has a configuration such that an annual ridge or a laterally expanded portion is provided to increase the contact area of the insert member which contacts the concrete, enhancing the insert member's anchoring performance to the concrete.
  • this conventional insert member is made of metal, it tends to have an inconveniently heavy weight to handle, and also tends to corrode in a rather short period.
  • the corrosion of the insert member causes the deterioration of not only the insert member itself but also of the concrete surrounding the insert member.
  • coloured plastic caps and the like attachable to the insert members are required to distinguish the insert members for a particular conduit from other insert members.
  • Insert members made of synthetic resin may solve the cost problem, however, it is not refractory and, this time, a problem with the insert member's yield strength would arise.
  • the plastic insert member has a neck-like portion, the potential of a crack or rupture would be increased because of stress concentration to the neck-like portion.
  • FIG. 1 shows an example of the insert member prepared according to the disclosure of this application.
  • This insert member 10 is of a truncated conical configuration and has a threaded hole 12 formed along the center axis of the insert member 10.
  • the smaller end face 14 of the insert member 10 is exposed so that a bolt member 20 can be screwed into the threaded hole 12.
  • the bolt member 20 is, for example, a conventional bolt including a threaded distal end portion 24 and a laterally expanded head portion (not shown).
  • the threaded hole 12 of the insert member 10 opens not only to the smaller end face 14 but also to the larger end face 16 of the insert member 10 so as to enable the bolt member 20 to be screwed in the hole 12 as far as the distal end 24 of the bolt member 20 reaches to the level of the larger end face 16.
  • This insert member is refractory, and, because of its improved configuration, it has less potential to undergo a stress concentration than conventional insert members.
  • a lid member 22 serving as a water stop must be fitted in the opening at the larger end face 16 to prevent the water in the concrete from exuding through the hole 12, the bolt member 20 is in practice not allowed to be screwed so deeply as might be expected.
  • FR-A-1,561,627 discloses an insert assembly for use in a concrete structure for mounting equipment onto a concrete surface, the insert assembly comprising: an insert member which is suitable for being embedded in the concrete structure; and a bolt member threadedly matable with the insert member and arranged to be anchored to and project from the concrete surface when the bolt member is mated with the insert member embedded in the concrete structure, said insert member having a tapered intermediate portion the tapered intermediate portion having an external tapered surface which is inclined outwardly with respect to the longitudinal axis (X) of the insert member towards one end of said tapered intermediate portion and having a threaded through hole which extends along said longitudinal axis past said end of said tapered intermediate portion into an end wall portion which is integrally joined to said end of said tapered intermediate portion and can receive the threaded end portion of the bolt member, said threaded through hole being closed by an end wall of said end wall portion and said end wall portion having a transverse outer size not larger than that of said end of the insert member.
  • the present invention provides an insert assembly as disclosed in FR-A-1,561,627, characterised in that the insert member is made of a ceramic material and the end wall portion is tapered away from said one end in the opposite sense to the taper of said intermediate portion.
  • the bolt member is allowed to be screwed in the threaded hole until the distal end of the bolt member reaches or advances past the junction of the tapered end wall portion and tapered intermediate portion of the insert member without damaging the watertightness of the insert member. Therefore, no axial tensile stress but rather an axial compressive stress is induced in the insert member. Accordingly, this insert member is capable of avoiding a crack or rupture due to a tensile stress, and shows a satisfactory rupture strength against the axial load applied to the bolt member.
  • the ceramic of which the insert member is made is an alumina ceramica silicon carbide ceramic or a silicon nitride ceramic.
  • the tapered surface of the intermediate portion of the insert member may for example be straight in axial cross-section.
  • the inclination angle of the tapered surface of the intermediate portion with respect to the longitudinal axis preferably, is not less than 1° and not greater than 45°.
  • the tapered intermediate portion may be of a truncated conical configuration, a truncated polygonal pyramidal configuration or a truncated elliptic conical configuration, for example.
  • the tapered surface of the intermediate portion of the insert member may be convexly curved in its axial cross section, for example.
  • the end wall portion may taper from its inner face to its outer face.
  • FIGS. 2 to 7 the same parts as those in FIG. 1 are designated by the same reference numerals, and descriptions thereof will be omitted.
  • FIG. 2 illustrate an insert assembly according to the present invention, in which reference numeral 30 designates a ceramic insert member adapted to be embedded in a concrete structure.
  • This insert member 30 consists of three portions, namely, an intermediate portion (hereinafter referred to as an insert body) 32 of a truncated conical configuration, a hollow cylindrical guide portion 34 coaxially and integrally joined to the smaller end of the insert body 32 and an end wall portion 36 integrally joined to the larger end 33 (which is shown by the phantom line) of the insert body 32.
  • the insert body 32 has a threaded hole 12 formed along the center axis X thereof.
  • the hollow 38 of the guide portion 34 is aligned and communicated with the threaded hole 12 of the insert body 32 to allow a bolt member 20 to be screwed in the threaded hole 12 therethrough.
  • the end wall portion 36 is of a truncated conical configuration of which larger end is coaxially connected to the larger end 33 of the insert body 32.
  • the diameter of the larger end of the end wall portion 36 in FIG. 2 is generally equal to that of the insert body 32, however, the former may be smaller than the latter.
  • the end wall portion 36 has a supplementary threaded hole 40 formed in the inner face thereof. This supplementary hole 40 is aligned and communicated with the threaded hole 12 of the insert body 32 to receive the distal end portion of the bolt member 20.
  • the internal thread 42 of the supplementary hole 40 is continuously formed from the internal thread 44 of the threaded hole 12, that is, the major and minor diameters of the thread 42 are equal to those of the thread 44, and also the leads of the threads 42 and 44 are equal to each other.
  • the tapered side face 46 of the insert body 32 is inclined at an angle ⁇ with respect to the longitudinal axis X of the insert member 30.
  • the angle ⁇ i.e., the cone generating angle of the insert body 32 is not less than 1° and not greater than 45°, and preferably in the range of 15° to 30°. Below 1°, the resultant insert member 30 is not expected to have a satisfactory anchoring performance to the concrete structure, whereas, at 45° and above, when an axial load is applied to the bolt member 20 mated with the insert member 30, there is a potential of a tensile stress being induced in the insert body 32, particularly, in the larger end portion of the body 32. The best rupture strength of the insert body 32 is obtained when the angle ⁇ is 15° to 30°.
  • the entire tube wall of the guide portion 34 has a uniform thickness, and the length L2 of the guide portion 34 is determined regarding the rupture strength of the entire insert member 30.
  • a mold made of a rubber substance and having an internal configuration which fits around the insert member 30 is prepared.
  • a threaded core member such as a bolt substantially equivalent to the bolt member 20 is coaxially fixed inside the mold.
  • Powdery material for ceramics such as Al2O3, SiC and Si3N4, having a particle size of about 20 to 30 ⁇ m is filled within the mold.
  • the air is eliminated from the inside of the mold, and thereafter, hydraulic pressure of 9.81 ⁇ 1010 N to 2.94 ⁇ 1011 N (1,000 to 3,000 t/cm2) is applied on the mold, forming a compact out of the powdery material.
  • the mold is removed from the resultant compact, and then the core member is unscrewed from the compact. Lastly, the compact is sintered at a temperature of about 1,700°C, resulting in the ceramic insert member 30 shown in FIG. 2.
  • the preparing of the insert member is simple and easy, and moreover, the inclination angle ⁇ of the insert body 32 which is from 1° to 45° is convenient for preventing any air spaces from being produced in the insert member during the preparation process. Accordingly, it is expected to efficiently manufacture high quality insert members with excellent dimensional accuracy.
  • the insert member 30 thus prepared is embedded, as shown in FIG. 2, in a concrete structure 18 to mount different equipments onto the surface 26 of the concrete structure.
  • the insert member 30 is detachably attached to the inner surface of a form for concrete placing, and then concrete is placed inside the form.
  • the attachment of the insert member 30 onto the form is achieved by fixing a projection member on the inner surface of the form and by firmly fitting the projection member in the hollow 38 of the guide portion 34.
  • the removal of the form after the hardening of the concrete results in the embedding of the insert member 30 in such a manner that the free end of the guiding portion 34 is exposed.
  • the bolt member 20 is threadedly engaged with the insert member 30 in mounting or securing an appliance, e.g., a gas conduit to the concrete surface 26, in other words, the appliance can be secured to the concrete surface 26 by means of the bolt member 20 screwed into the threaded hole 12 of the insert body 32 through the hollow 38 of the guide portion 34.
  • an appliance e.g., a gas conduit to the concrete surface 26
  • the appliance can be secured to the concrete surface 26 by means of the bolt member 20 screwed into the threaded hole 12 of the insert body 32 through the hollow 38 of the guide portion 34.
  • the bolt member 20 thus securing the appliance on the concrete surface, particularly when it serves as a hanging bolt, is usually subjected to an axial load which urges the bolt member 20 in a direction indicated by arrow C.
  • This axial load is transmitted to the concrete structure 18 via the tapered side face 46 of the insert body 32, whereby the reaction force is applied uniformly to the conical side face 46 by the concrete structure 18.
  • the bolt member 20 since the bolt member 20 is engaged with the insert member 30 as deeply as the distal end 24 reaches or proceeds over the larger end 33 of the insert body 32, no axial tensile stress but an axial compressive stress is induced in the insert member 30.
  • this ceramic insert member 30 can avoid a crack or rupture due to a tensile stress, and shows a satisfactory rupture strength against the axial load applied to the bolt member 20. Furthermore, because of the wedge-like configuration of the insert body 32, the more load the bolt member 20 is subjected to, the more firmly the insert member 30 contacts the concrete structure 18. The result is that the insert member 30 in connection with the concrete structure 18 shows an excellent anchoring performance.
  • the bolt member 20 may be advanced or drawn back as long as the distal end 24 of the bolt member 20 is within the supplementary hole 40. That is, in this insert assembly, it is enabled, without bringing the distal end 24 of the bolt member 20 to a position halfway in the threaded hole 12, to adjust the length of the projecting portion 50 to a length of L3 to L3 + dL, where dL is equal to the length L4 of the supplementary threaded hole 40 (see FIG. 2).
  • FIG. 4 illustrates a modified form of the insert member in FIG. 2, in which a cylindrical guide portion 54 is separately formed from the remainder of the insert member 52 and the guide portion 54 is detachably connected to the smaller end 56 of an insert body 58. More specifically, the threaded hole 12 is provided at its opening with an engaging section 60 having a larger inner diameter than the remainder of the threaded hole 12, and one of the opposite end sections of the guide portion 54 is fitted in the engaging section 60.
  • the distance S between the concrete surface 26 and the insert body 58 it is possible to adjust the distance S between the concrete surface 26 and the insert body 58 by connecting the guide portions of different lengths to the insert body 58.
  • FIG. 5 shows another modified form of the insert member in FIG. 2, in which an insert body 62 is tapered toward a guide portion 64 in such a manner that the tapered side face 66 thereof in an axial cross section is convexly curved.
  • Reference numeral 68 designates a recesse formed in the side face of the insert member 70 to avoid rotational movement of the insert member 70 when it is embedded in the concrete.
  • the reaction force to be exerted on the tapered side face 66 by the concrete structure 18 reduces gradually toward the larger end of the insert body 62 whereby, when the bolt member 20 is not screwed in the threaded hole 12 so deeply as the distal end 24 comes into the supplementary hole 40, the tensile stress to be induced in the larger end portion of the insert body 62 is considerably less than that to be induced in the insert body 32 shown in FIG. 2.
  • the insert bodies 32, 58 and 62 and the end wall portion 36 are of truncated conical configurations, they may be of truncated polygonal pyramidal configurations or of truncated elliptic conical configurations. In such configurations, the insert members are enabled to prevent rotational movement when they are embedded in the concrete. Furthermore, instead of the end wall portion 36, an end wall portion of a cylindrical configuration may be employed. This cylindrical end wall portion must have an outer diameter smaller than that of the larger end of the insert body.
  • insert members in the preceding embodiments may be colored during their preparation in order to distinguish themselves from other insert members used for different purposes. More specifically, when the insert members for different conduits, that is, for instance, an electric cable conduit, a gas conduit, a water conduit and an air conduit, are colored differently, securing operation for each conduit onto the concrete surface is made efficient and effective, and mistakes in securing operation is reduced.
  • This test insert member 30 was embedded in the concrete structure 18 as shown in FIG. 6.
  • a steel tension bar 72 having a threaded end portion is threadedly engaged with the test member 30.
  • Axial tensile load was applied to the tension bar 72 by means of a ram chair 74 and jack 76 fixed above the test member 30, and was increased until any one of the test member 30, tension bar 72 and concrete structure 18 was broken.
  • the tensile load applied to the tension bar 72 was determined by a load cell 78 which was operatively connected to the jack 76. The result was that the concrete structure 18 was broken as shown in FIG.
  • This value of the determined tensile load Pb i.e., the compressive load applied to the test insert member upon the destruction of the concrete structure 18 is shown in Table 1 with the design load Pd of the insert member.
  • the design load Pd of the test insert member is defined by the same formula given in Example 1.
  • the breaking load of the test insert members is substantially greater than the design load thereof, that is, the insert member according to the present invention has excellent rupture strength.

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  • Engineering & Computer Science (AREA)
  • Architecture (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Joining Of Building Structures In Genera (AREA)
  • Details Of Spanners, Wrenches, And Screw Drivers And Accessories (AREA)
EP88301377A 1987-02-20 1988-02-18 Insert assembly for use in a concrete structure Expired - Lifetime EP0279675B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP1987023744U JPS63132001U (hr) 1987-02-20 1987-02-20
JP23744/87 1987-02-20

Publications (2)

Publication Number Publication Date
EP0279675A1 EP0279675A1 (en) 1988-08-24
EP0279675B1 true EP0279675B1 (en) 1991-11-06

Family

ID=12118818

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88301377A Expired - Lifetime EP0279675B1 (en) 1987-02-20 1988-02-18 Insert assembly for use in a concrete structure

Country Status (4)

Country Link
EP (1) EP0279675B1 (hr)
JP (1) JPS63132001U (hr)
KR (1) KR950011054B1 (hr)
DE (1) DE3865982D1 (hr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2591747B (en) * 2020-02-04 2022-03-02 Ischebeck Titan Ltd Anchor assembly

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3418781A (en) * 1967-01-12 1968-12-31 Cleveland Trencher Co Bolt anchor for concrete
CH500388A (de) * 1967-04-05 1970-12-15 Aackersberg Mortensen Dübel zum Einbetonieren
JPS5354383Y2 (hr) * 1974-07-31 1978-12-26
US3982363A (en) * 1974-10-18 1976-09-28 Ddk Investments, Ltd. Frangible insert
US4368606A (en) * 1979-07-31 1983-01-18 Sanyo Industries, Ltd. Socket means for embedment in a concrete slab

Also Published As

Publication number Publication date
KR890013295A (ko) 1989-09-22
JPS63132001U (hr) 1988-08-30
DE3865982D1 (de) 1991-12-12
EP0279675A1 (en) 1988-08-24
KR950011054B1 (ko) 1995-09-27

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