PL186090B1 - Mining hook bolt - Google Patents

Abstract

Mining hook bolt intended for fastening reinforcements of a roadway support frame, characterized in that it has at least one advantageously selected reinforcement (2) stably attached to the outer edge of the bend (1b) of the hook bolt (1), so that the force bending the bent part (1a) is approximately equal to the breaking force of the hook bolt (1).

Description

The subject of the invention is a mining hook bolt intended for fastening reinforcements of a mining support frame, e.g. beams, struts, etc.

Known and commonly used hook bolts have a bent curved part placed inside the trough section of the mine support support frame and a straight outer part with a threaded tip, e.g. hook bolts described in the article Chmielewski W., Łaboński S, Taborek W .: U-bolt stirrups for connecting arches and strengthening the housing. Mining News 1997, No. 5.

A general disadvantage of all previous hook bolts is the relatively low force causing the bent portions of the hook bolts to flex.

This makes it necessary to make hook bolts from large diameter rods. The consequence is the relatively large weight and price of the currently used hook bolts, as well as the disproportion of the force values: bending the hook and breaking the hook bolt,

The above-mentioned disadvantages are eliminated by a mining hook bolt made according to the patent application.

The effect of the reinforcement (2) of the bent part (1b) of the hook bolt (1) is a significant increase in the force causing the bending of the bent part (1a) of the hook bolt (1). Preferably selected: the cross-section of the reinforcement (2) and the length (L) of the bent part (1a) of the hook bolt (1) make it possible to obtain almost equal forces breaking the hook bolt (1) and bending the bend parts (1a).

The hook bolt according to the patent pending patent has a much lower weight compared to comparable hook bolts of the previous solutions with a higher breaking strength, and thus is correspondingly cheaper and safer.

The subject of the patent application is shown in Fig. 1.

A mining hook bolt is made of two, e.g. round rods. The bar (1) is bent in the shape of a hook having suitable dimensions of the straight portions (1a) and (1c), the longer section of the mining hook bolt having a thread (1d). The reinforcement (2) is made of a preferably selected rod bent so that the inner edge (2a) of the reinforcement (2) adjoins the outer edge (1b) of the mining hook bolt (1). The reinforcement (2) is firmly connected to the bolt (1), e.g. by welding.

The bent part (1a) of the hook bolt (1) preferably has a length (L) selected so that it is greater than the minimum radius (Rm), the value (R _mi ") being between the pivot point (B) and the point (Amin.). At the same time, the support radius (R) of the bent part (Ia) of the hook bolt (1) should be greater than the value of the minimum radius (R _mi ") and less than or equal to the value of the maximum support radius (R _mai ). The radii (Rmin), (R) and (R _m J) lie between the pivot point (B) and the respective points (A min), (A) and (A _max ). The reinforcement cross-section (2) and the length (L) are advantageously

186 090 so that the hook bending force of the bolt (1a) is approximately equal to the thread breaking force (1d) of the mining hook bolt (1).

The mining hook bolt is mounted on the support arches of the section (3) using a previously known method, e.g. described in the article: Chmielewski W., Łaboński S., Taborek W .: U-bolt stirrups for connecting arches and reinforcing the support. Mining News 1997, No. 5.

186 090

Publishing Department of the UP RP. Circulation of 50 copies. Price PLN 2.00.

Claims (2)

Patent claims 1. Mining hook bolt intended for fastening the reinforcements of the roadway support arch, characterized in that it has at least one preferably selected reinforcement (2) firmly attached to the outer edge of the bend (1b) of the hook bolt (1) so that the bending force ) was approximately equal to the breaking force of the hook bolt (1). A mining hook bolt (1) made according to the first claim, characterized in that the bent part (1a) of the hook bolt (1) preferably has a selected length (L), so that the condition: (L)> (R _nin ) is met, for which the size of the backrest radius (R), measured between the pivot point (B) and the support point (A), is within the range ORm) <(R) <Ο ^ ηιιχ)