US3699687A

US3699687A - Arrangements for anchoring supporting pins or bolts

Info

Publication number: US3699687A
Application number: US8914A
Authority: US
Inventors: Andre Bourland
Original assignee: Celtite SA
Current assignee: Celtite SA; Sa D'explosifs Ind-Celtite
Priority date: 1969-02-10
Filing date: 1970-02-05
Publication date: 1972-10-24
Anticipated expiration: 1989-10-24
Also published as: CA943780A; DE2005161A1; DE2005161B2; GB1303723A; AU1109870A

Abstract

A device is provided for use in anchoring a support pin in a hole adapted to accommodate the same. The device comprises a hollow elongated element of open work construction and made of a friable material. This element contains a charge which is adapted to protrude through the open work construction when subjected to the pressure of a pin inserted in the aforesaid hole whereafter the friable material of the open work construction fragments during further insertion of the pin and becomes homogeneously distributed into the charge. A device is provided to brace the element in the hole adapted to receive the pin.

Description

United States Patent Bourland 1 Oct. 24, 1972 [54] ARRANGEMENTS FOR ANCHORING 3,324,662 6/ 1967 McLean ..61/45 X SUPPORTING PINS OR BOLTS 3,385,427 5/ 1968 Stouls ..6l/45 B X 3,430,449 3/1969 Novotny et al ..6l/45 B [72] Invent Andre Q France 3,474,898 10/1969 Montgomery ..-.6l/45 B x [73] Assignee: Societe Anonyme DExplosifs Indusmels-Cemte Primary ExaminerDennis L. Taylor [22] Filed: Feb. 5, 1970 Att0rney-Waters, Roditi, Schwartz & Nissen [21] Appl. No.: 8,914

[57] ABSTRACT [30] Foreign Application Priority Data A device is provided for use in anchoring a support pin in a hole adapted to accommodate the same. The 1969 France "6903015 device comprises a hollow elongated element of open 1969 France? "694.0901 work construction and made of a friable material. This element contains a charge which is adapted to (g1. 61/42:; protrude through the p work construction when 58 d /698 704 subjected to the pressure of a pin inserted in the l 1 0 care f aforesaid hole whereafter the friable material of the open work construction fragments during .further in- [56] References cued sertion of the pin and becomes homogeneously dis- UNITED STATES PATENTS tributed into the charge. A device is provided to brace UX the element in the hole adapted to receive the pin. 2,570,003 10/1951 Palmer ..61 45 B 2,930,199 3/1960 Jarund ..6l/45 B 2,849,866 9/ 1958 Flygare et a1. ..52/704 X 9 Claims, 6 Drawing Figures 3,108,443 10/1963 Schuermann et al. ...52/698 X 3,298,144 1/1967 Fischer ..61/45 B X PATENTEflum 24 1972 SHEET 1 OF 3 FIG. 2a.

ARRANGEMENTS FOR ANCHORING SUPPORTING PINS R BOLTS For many years supporting pins or bolts, hereinafter referred to as pins, have been used to brace rocky walls both in mines and public works, the pins being sealed in place by a cement or synthetic resin.

In this latter case, the resin added to the materials required for polymerization (accelerator, filler and hardener) may be injected into the base of a hole pierced in the rock or in the wall to be braced. It may also be inserted into the hole, contained in a suitable holder having one or more compartments which are destroyed when the pin is inserted in the hole, the components, viz. the resin, filler and accelerator on the one hand, and hardener on the other hand, being mixed by rotation of the pin itself.

The different methods of holding the charge used hitherto have serious drawbacks which have, on occasions, caused accidents.

In fact, various materials have been proposed as holders and, in particular, treated or non-treatedpaper, cardboard, glass, 'a supple plastic sheath, bakelite, plastics materials, etc. have been so used. All these holders have great disadvantages. Those which are rigid shatter badly when the pin is introduced and often their fragments form plates which lodge between the pin and the resin or between the resin and the wall of the hole, therefore, considerably reducing the grip on the pin.

Those which are supple often tear badly, and form thin strips which wind themselves about the pin, hindering the adhesion of the resin or causing areas of low resistance to appear which form the beginning of splits in the sealing.

Moreover, when the resin and its hardener are contained in capsules made of a rigid and brittle material, it is very difficult to use them practically in mines and public works, because a holder of this type (glass, in particular) frequently shatters either during transport or when it is being handled on site; the fluid or semifluid putty therefore escapes and not only renders the charge itself unusable but also any adjacent charges.

When the holder is supple, the above drawback is avoided, but if the capsules are short as compared to their diameter, when they are manipulated they take the shape of a banana which makes it difficult to insert them into the holes and prevents the use of automatic pinning or bolting machines.

It is an object of the present invention to remedy or minimize these various drawbacks and to provide an efficient and practical means allowing rapid and safe sealing to be produced with the aid of machines which may be automatically operating, if desired.

To this end, the invention consists more particularly in using, in order to contain the cement compound, a tubular cartridge, preferably round in section, of a suitable length, and formed by a perforated tube forming a net or wire netting of a friable material such that, when the pin is introduced, the cement components are intermixed and this net is reduced to fragments of small size also mixing with the cement during hardening in a homogenous manner, and contributing to its adhesion to the walls of the receiving bored hole. The friable material can be a synthetic resin such as polystyrene or polyvinyl chloride.

It is convenient to mention here that for the same purpose, breakable but non-perforated tubes have already been suggested, which would therefore not insure this homogenous distribution of the fragments within the cement. Also perforated tubes are known which were not intended to shatter, the orifices which they have only being intended to allow the cement to escape outwardly when the pin is introduced.

According to a particular embodiment of the invention, this tube is used in combination with a charge within a plastic sheath such as described hereinbefore. In this case, such a sheath when it breaks, does not cause the introduction of barriers and destroying the adhesion'of the cement with the wall of the hole.

According to a first embodiment of the invention, the resin itselfis simultaneously introduced into the aforementioned tube, usually added to a small quantity of accelerator of the polyester type, having the necessary products for polymerization (hardening catalyst, usually benzoyl peroxide), and a filler considered as inert (dolomite, talc.) and to cause the suitable mixing of these products when the pin to be sealed, is introduced.

According to a second embodiment of the invention, the charge elements, instead of being grouped in concentric zones, namely in an axial rod formed from the catalyst itself, then an annular area formed by a mixture of the resin, the accelerator and the inert filler, the whole usually being held in a sheath made of a supple plastic material and lodged in the rigid elongated tube made of a friable material, are introduced into this latter but in the form of individual separate quantities, each into a section of the supple sheath and alternatively, lengthwise, an amount of pure resin (excluding the accelerator), then an amount of the mixture of the catalyst and the inert filler, then a quantity of the pure resin and so on.

There appears therefore, three fundamental differences in this second method of charging, namely:

The resin is introduced in a pure form (without accelerator) and not previously mixed with the inert filler which is mixed with the catalyst.

The products are separated from each other in th sealed supple sheaths.

The quantities of the different materials are placed end to end and not concentrically.

The advantages of these three factors are considerable: Firstly, from a practical point of view, the end-toend arrangement allows the mixing of the product to be insured by simply axially depressing the pin without rotating it. It is known in fact that in the former methods of presentation it was necessary to depress the pin and rotate it at the same time, due to the fact that the mixing was not satisfactory.

Furthermore, it was not possible axially to depress the pin to be sealed, since this would lead to pushing away the axial rod of the catalyst.

On the contrary, in the case of elements arranged longitudinally one after the other in alternate fashion, the simple depression of the pin which may, without disadvantage, be axial, has the effect of insuring mixmg.

Secondly this arrangement improves the storage and sealing properties. This double advantage results from the fact that the resin is in a pure state without the inert filler which accompanies it in the prior systems. Moreover, such an inert filler is not usually completely free of impurities so that when it is mixed may be stored in advance, instead of preparing them on site. Moreover, as a result the sealing quality is improved in a manner corresponding to the best quality of the resin.

Finally, it will be apparent that the alternate quantities may be of any size, the final mixture being all the better in proportion as the quantities are short and greater in number. This advantage may be elaborated upon even further if the composition of the quantities is allowed to vary along the same charge, which was impossible with the former concentric charges. This becomes useful for example in the case where very long pins have to be sealed, e.g. of a length of 6 to 8 meters, which must be immediately fixed at their inner end, but on the contrary only progressively fixed over the remainder of their length, without the danger of undesirable tensions arising. This distribution of the hardening action is rendered possible due to the invention by modifying the composition of the quantities, the rear portion of the charge going to the base of the hole comprising a larger dose of catalyst, while the remainder of the charge comprises on the contrary a quantity of this catalyst sufficient to cause only a slow setting of the resin.

The invention, therefore, relates by way of particular embodiment to the new industrial product which forms a sealing charge of the usual type defined hereinbefore and wherein, moreover, the distribution of the quantities of accelerator is such that the behavior of the charge is different along the various regions of its length.

In order that the invention may be more clearly understood, reference will now be made to the accompanying drawings which show one embodiment thereof by way of example, and in which FIG. 1 shows in perspective a perforated tube according to the invention,

FIG. 2 shows in axial section the same tube containing a charge without a plastic sheath,

FIG. 2a shows a modification of the arrangement of FIG. 2,

FIG. 3 shows the charge in place in the hole for receiving the pin, and

FIGS. 4 and 5 show schematically and respectively the behavior of a conventional perforated tube and one according to the invention when the pin is inserted.

Referring to FIG. 1, it will be apparent that a tube according to the invention is cylindrical in shape and formed by coiling a net or piece of wire netting, whose sides 1 are very thin and define a mesh 2 which may be of any shape, for example, square, diamond-shaped or round. The material of the net is friable and made of a synthetic resin material such as polystyrene or polyvinyl chloride. A bendable flange 3 is inserted across this mesh and its clips may assume the position 3' (FIG. 2) to hold the tube in its hole 4 (FIG. 3) once it is introduced.

As can be seen from FIG. 2, the sealing charge is lodged within the tube. The charge is formed from one or more capsules 5 formed by a sealed envelope containing the synthetic resin putty and its hardener 6 and these may be either contiguous, mixed or not, or separated, as desired. FIG. 2 shows one capsule and FIG. 2a shows capsules 5a in contiguous relation. The sealed envelope may be made of any suitable material such as sheaths or sheets of plastic material, treated or non-treated papers, glass, bakelite,

synthetic tubing, cellulose, etc. t

The resin putty in the capsule 5 and the hardener 6 may be located in different holders made from different materials. Cement, resins, thermo-hardening resins or gums may also be used, the invention not being dependent upon the kind of adhesive used.

Therefore the rigidity and protection of the charge are insured by the outer net tube, and the sealing by the capsules.

If, on any occasion, the net tube breaks at one point, the putty, even when liquid, remains in the inner.envelope and does not spread at all.

Finally, the capsule or capsules-may be held in place in the net tube by the star-shaped flanges 3 which also insure that the sealing charge is held in the hole when the arrangement is put into use.

The method of using these charges is next explained with reference to FIGS. 3, 4 and 5: when sealing is to be effected, the cartridge, according to the invention, is inserted into the base of a hole 4 bored in the rock to be braced or in the material in which the pin 7 is to be fixed, the hole obviously being of a diameter greater than that of the cartridge, the star-shaped flange 3 allows the fitting of the cartridge in the base of the hole if this latter is upwardly directed.

Then the pin 7 to be sealed is inserted. The end of the pin comes to rest against the base of the sealing 'car-' tridge and if the inner capsule is, as it is most frequently made of a supple material, the resin is compressed and the lateral envelope of the capsule bulges through the holes 2 of the tube. When the pin continues to progress towards the base of the hole, it forms a piston and even when the capsule 5 is split or shattered, the pressure of the resin makes the bulges aforementioned, burst, thus preventing the supple envelope or envelopes from tearing into strips of material which would impair the adhesion of the pin to the putty and wall, or create points of low resistance for the sealing.

While passing through the holes 2 of the net tube, the putty is mixed with its hardener and it is not necessary to rotate the pin in order to obtain a correct mixture and good sealing. FIGS. 4 and 5 allow the differences in behavior between the conventional perforated tube (FIG. 4) and the friable tube, according to the invention (FIG. 5), to be appreciated.

In both the Figures, the pin 7 has been shown in its final position, having been pressed axially into the tube containing the sealing charge.

In the case of the conventional perforated metal tube (FIG. 4), the resin has been pushed through the perforations 8 of the tube 9 so as to fill the space between the tube and the wall of the hole. This filling is more or less aleatory and its homogeneity is not guaranteed. Moreover, the fragments in the shape of strips of material of the capsule are also pressed back by the perforations 8 and may come into contact with the wall of the hole, thus preventing the adhesion of the sealing at this point.

On the contrary, according to the invention, the insertion of the pin 7 into the charge not only makes the plastics capsule 5 burst but also the breakable tube, the small fragments of which form a filler for the putty, so that the pin is embedded in a homogenous mass which insures its holding and support in the hole 4.

Naturally, variations of the embodiment which has just been described are easy to imagine: for example, the tube may be as long as the bored hole and even if a long divided sealing is required a single load may be used.

Moreover, the capsule is not of necessity the same length as the net tube and several capsules of suitable sizes which may be separated by spaces, may be used within the same net tube.

The capsules or capsule may be simple or multiple and contain the putty and the hardener either in the same envelope, mixed or contiguous, or in distinct compartments of the same envelope.

The putty and the hardener may again be located in separate capsules of large or small size (small tubes, balls, beads, etc.) placed alternately or in mixture in the net tube.

Of course, all that has been stated as regards the putty and its hardener, also applies to a cement, gum or an other suitable adhesive material and all combinations are possible between the various methods as described hereinbefore.

What we claim is:

l. A device for use in anchoring a support pin, said device comprising a hollow elongated element of openwork construction, a capsule within said hollow elongated element and containing a charge of cement-forming material for anchoring the support pin, said capsule being so constituted that the capsule bursts through the open work construction when subjected to pressure upon insertion of the pin, said element of open work construction being made of a friable material to fragment during further insertion of the pin and to become homogeneously distributed into the cement-forming material to contribute to the anchoring of the pin in the hole.

2. A device as claimed in claim 1, wherein the friable material consists of a synthetic resin.

3. A device as claimed in claim 2, wherein the synthetic resin is polystyrene or polyvinyl chloride.

4. A device as claimed in claim 1, wherein the charge comprises a resin and a hardener therefor, located together in said capsule.

5. A device as claimed in claim 4, wherein said capsule is a supple plastic material.

6. A device as claimed in claim 1, wherein the capsule comprises a rigid and friable envelope and includes a synthetic putty in the form of an accelerated but unhardened polyester resin, a hardening catalyst and an inert filler, these components being arranged to be mixed together on the insertion of the pin to be anchored, said accelerated resin and the said mixture of catalyst and filler being contained in separate supple sheaths located behind one another in the rigid envelope.

7. A device as claimed in claim 6, wherein the envelope contains a number of amounts of resin and of a catalyst/inert filler mixture, distributed alternately throughoutthe length of said envelope.

8. device as claimed in claim 7, wherein the amounts of said resin and said mixture differ along the length of the envelope so as to vary the characteristics of the hardening operation along the length of the envelope.

9. A device as claimed in claim 8, wherein the front end of the envelope contains amounts of resin/catalyst filler mixture having a very rapid hardening characteristic, while the remainder of the length of the envelope, contains materials arranged to harden at a much slower rate.

Claims

1. A device for use in anchoring a support pin, said device comprising a hollow elongated element of open-work construction, a capsule within said hollow elongated element and containing a charge of cement-forming material for anchoring the support pin, said capsule being so constituted that the capsule bursts through the open work construction when subjected to pressure upon insertion of the pin, said element of open work construction being made of a friable material to fragment during further insertion of the pin and to become homogeneously distributed into the cement-forming material to contribute to the anchoring of the pin in the hole.

7. A device as claimed in claim 6, wherein the envelope contains a number of amounts of resin and of a catalyst/inert filler mixture, distributed alternately throughout the length of said envelope.

8. A device as claimed in claim 7, wherein the amounts of said resin and said mixture differ along the length of the envelope so as to vary the characteristics of the hardening operation along the length of the envelope.