US3415064A - Supporting device for rock walls - Google Patents

Description

D60 1968 .1. A. TALOBRE SUPPORTING DEVICE FOR ROCK WALLS Filed April 17, 1967 I N VEN TOR. A. 7391 05/25 HTTOfi/VEYS United States Patent 5 Claims. for. 61-45) ABSTRACT OF THE DISCLOSURE A device used in combination with rock bolts for supporting rock walls including a plurality of shell-shaped members through which one end of a rock bolt passes and is fastened. The members have long extending arms which effectively engage a large substantial surface of the wall.

This invention relates to construction apparatus generally, and more particularly, to a supporting device for rock walls, or the like.

Heretofore, it has been the practice to use steel plates firmly bonded to rock surfaces by means of rock bolts which pass through the rock wall and are secured to the plates at one end by a nut for purposes of supporting rock walls of tunnels, mines, and the like. Usually, these plates are flat, thick, square and have a relatively small engaging surface. These prior art devices were not completely satisfactory for many reasons. They were relatively heavy, and consequently expensive to fabricate. They were inefiicient because they engaged a small surface of the rock, and when a high restraining load was required, the rock tended to rupture by crushing.

The present invention contemplates a structure which overcomes the defects of the prior art devices. In essence, the present invention comprises a new and improved device for use in conjunction with a rock bolt for supporting rock walls. The device includes a convex shell-shaped member which has a central zone with a hole therein for the passage of the rock bolt. Means are provided for connecting the bolt to the member. This member has a plurality of radially extending arms which are adapted to engage the rock wall when the device is in its operating position.

As a feature of this invention, the convex shell-shaped member is axially resilient in order to enhance its ability to grip a rock wall. This resiliency serves to improve the gripping action particularly when the rock surface is irregular, thereby insuring a greater distribution of the load. Moreover, this resiliency helps to limit the forces bearing on the rock bolt and nut. Also, the resiliency of the supporting device allows it to adapt to rock bolts disposed at oblique angles with respect thereto, thereby reducing the risk of failure due to bending moments.

As another feature of the invention, the radially extending arms have axially inwardly projecting edges which enhance the gripping action with the rock wall. This increases the moment of inertia of the arms without losing the elasticity of the supporting device. Also, this provides a cavity of space for the introduction of cement grouting between the rock wall and the supporting member. The arms may be provided with openings for filling this space with the grouting. Moreover, the end of the arms may be provided with grasping claws to assist in engaging the rock and to insure contact between the device and the rock wall at points disposed a substantial distance one from the other, thereby spreading the reaction forces against the rock wall over a substantial distance.

Further, the device according to the invention may have a dome or convex shell-shaped member which has a 3,415,064 Patented Dec. 10, 1968 ice cavity of axial depth which may be filled with cement grouting. This grouting serves to improve the disposition of the load forces on the rock wall as well as protecting the bolt head and nut against rusting after long periods of service.

According to one aspect of the invention, the arms are symmetrical and in the shape of a star or rose. Preferably, three arms are employed, which is satisfactory from an operational standpoint and is economical to fabricate.

According to the invention the convex shell-shaped member may be fabricated with a thin wall such as from steel plate, for example. Certain plastic materials may be employed for their anti-rust properties, if desired. The combination of a thin wall with a star configuration of the supporting member serves to provide a large resilient supporting area, thereby limiting the compression stress against the rock wall, and hence, reducing the possibility of crushing said wall. Moreover, the shape of the supporting member renders it possible to employ a plurality of members in superimposed positions, one with respect to the others.

According to another aspect of this invention, the center zone of the convex shell-shaped member has a semispherical surface having a central opening through which passes the end of the rock bolt. This end of the rock bolt is threaded and a nut and washer are secured thereto. The washer, if a washer is employed, or else the nut itself, is adapted to bear against the inside of the semispherical surface, thereby permitting the rock bolt to be disposed at any oblique angle with respect to the wall supporting member.

There has thus been outlined rather broadly the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter which will form the subject of the claims appended hereto. Those skilled in the art will appreciate that the conception on which this disclosure is based may readily be utilized as the basis for designing of other structures for carrying out the several purposes of the invention. It is important, therefore, that the claims be regarded as including such equivalent constructions as do not depart from the spirit and scope of the invention,

Several embodiments of the invention have been chosen for purposes of illustration and description, and are shown in the accompanying drawings, forming a part of the specification, wherein:

FIG. 1 is a perspective view of a device constructed in accordance with the concept of this invention; and

FIG. 2 is a medial cross-sectional view of the supporting device as applied to a rock wall.

In the embodiment of the invention illustrated in FIG. 1, the supporting device includes a convex shell-shaped member indicated generally at 10, this member has a central zone 12 with a central opening 14 for the passage of one end of a rock bolt 16, as seen in FIG. 2.

The member is axially resilient. That is, the member is resilient in a direction substantially parallel to the rock bolt 16 for purposes of improving the gripping action with the surface of the rock wall 18, FIG. 2. Further, as seen in FIG. 2, this resiliency improves the gripping action when the rock wall 18 is of irregular configuration, as shown at 20, and it also allows the rock bolt 16 to be disposed at an oblique angle with respect to said member 10, as shown at 22.

Referring again to FIG. 1, it will be appreciated that the member 10 is symmetrical and is generally rose or star shaped, and preferably has three radially extending arms 24, 26, and 28. This serves to extend the member over as large an area of the rock wall as possible without unduly increasing the overall size of the member.

As best seen in FIG. 1, a member is provided with inwardly projecting edges 30, 32 and 34 which enhance the gripping action of the rock wall. Also, the arms are provided with claws 36, 3S and 40 for additional gripping action and to spread the reaction forces against the rock wall over a substantial area.

The member 10 is dome or convex shell-shaped forming a cavity 42 of axial depth. The inwardly projecting edges 30, 32 and 34, as well as the claws 36, 38 and 40 help to form outside walls for the cavity 42. The member 10 is provided with opening 44, one being shown in arm 26, FIG. 1, for filling the cavity 42, FIG. 2 with cement grouting 43. The entire cavity may be filled with grouting and serves to spread the load forces acting against the rock wall over a large area, thereby removing the concentration of same. This also improves the gripping action between the member 10 and the rock wall 18.

Referring to FIG. 2, the rock wall 18 has a bore 46 through which a rock bolt 16 passes. The contra-zone 12 of the member 10 has asemi-spherical surface 48 having a central opening 14 through which passes one end of the bolt 16. This end of the bolt is provided with a screw thread on which a washer 52 and a nut 54 are applied. The washer 52, or if no washer is employed, the nut 54 engages the semi-spherical surface 48 as at 56 to secure the member 10 against the rock wall 18 with considerable force. It will be appreciated that the rock bolt 16 may be disposed at any oblique angle 22 with respect to the rock wall and member 10 and still be held firmly in position. It will be noted that the cement grouting 43 also serves to prevent the bolt head and nut from corroding after long periods of installation.

Preferably, the member It) is fabricated with thin walls and from steel plates by cutting and machining, for example. It provides a resilient, durable member.

In another form of the invention, a second convex shell-shaped member 10' of identical shape as the first convex shell-shaped member 10 described hereinbefore may be interposed between the first member 10 and the rock wall 1.8. This serves to allow for an increased force to be applied to the rock wall 18. Employing a plurality of superimposed members has a number of advantages including allowing mass production of members which may be used for various installations, each having individual force requirements. Also, the transportation and installation of a plurality of members is simpler than employing a single, heavy, large member.

Thus, it is seen that applicant has indeed provided a new and improved supporting device which effectively meets the objects specified hereinbefore.

Although particular embodiments of the invention are herein disclosed for purposes of explanation, further modifications thereof, after study of this specification, will be apparent to those skilled in the art to which the invention pertains. Reference should accordingly be had to the appended claims in determining the scope of the invention.

What is claimed and desired to be secured by letters patent is:

1. A device for use in combination with a rock bolt for supporting rock walls, said device comprising a plurality of convex shell-shaped members having a central open ing for the passage of one end of the rock bolt, means for connecting said bolt to said member, and said members having long extending arms which are effectively engageable with said rock wall on a large substantial surface when in operating position.

2. A device for use in combination with a rock bolt for supporting rock walls according to claim 1, wherein said member is of high rigidity and is fabricated for thin steel plating.

3. A device for use in combination with a rock bolt for Supporting rock walls, said device comprising a convex shell-shaped member having a central zone with a central opening for the passage of one end of the rock bolt, said member being axially resilient, said member being substantially star shaped and having three radially extending arms, said member having inwardly projecting edges for gripping said rock wall, said arms having claws disposed at the ends thereof for gripping said wall, said arms having openings for the passage of grouting, said member having a cavity of axial depth for receiving grouting between said member and said rock wall when in its operating position, a nut and a washer fastenable on the end of said bolt, said central zone having a semi-spherical surface for receiving said bolt and washer, whereby said bolt may be obliquely disposed with respect to said member.

4. A device for use in combination with a rock bolt for supporting rock walls, said device comprising a plurality of convex shell-shaped members which are used in superimposed relationship one with respect to the next adjacent one, said members having a central zone with a central opening for the passage of one end of the rock bolt, means for connecting said bolt to said members, and said members having a plurality of radially extending arms which are engageable with said rock wall when in operating position.

5. A device for use in combination with a rock bolt for supporting rock walls, said device comprising a convex shell-shaped member having a central zone with a central opening for the passage of one end of the rock bolt, said member being axially resilient for gripping said rock wall when in operating position, means for connecting said bolt to said member, and said member having a plurality of radially extending arms which are engageable with said rock wall when in operating position, said arms having axially inwardly projecting edges which grip said rock wall when in operating position, said arms having openin gs therein for filling the space between the member and the rock wall with grouting.

References Cited UNITED STATES PATENTS 3,090,203 5/ 1963 Durget 6145 3,226,934 1/1966 Emery 61-45 FOREIGN PATENTS 968,630 9/1964 Great Britain.

JACOB SHAPIRO, Primary Examiner.

U.C. Cl. X.R. -50, 62

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