CA2104940C - Portable mechanized mine scaling tool - Google Patents

Abstract

A portable, mechanized scaling tool for the dislodging of unstable rocks from the walls of underground mine passageways comprising a telescopic handle from one to two meters in length and a tool point of innovative geometry having a longitudinal axis and two ends, an angular shank with another longitudinal axis, a length and two sides, an elongated S-shaped junction portion, an anvil with an elongated body and two ends intended to be axially displaced, and a means of periodic displacement acting on the anvil. The tool point generates a lever effect on the unstable rocks which results in their rapid dislodgment while minimizing the bending effort of the operator, facilitating the work and improving the safety of the operators and the work areas. The scaler is lightweight and ergonomically designed, adapting to the worker's natural position.

Description

General Field of the Invention This invention is related to the field of mining tools, and more particularly to mining tools used for scaling unstable rocks in underground mine passageways.

Summary of Previous State of the Art The scaling of rocks consists of using a steel bar to probe the walls of an underground mine passageway in order to detect and detach unstable rocks, which constitute a potential cause of accidents. Currently, this operation is carried out manually and is, in itself, dangerous. The maneuvering of a steel bar (with a weight of about 5kg), requires a great deal of human energy, which substantially increases the risk of injuries related to the mishandling of the bar, the use of an improper bar or an incomplete scaling job.
U.S. Patent No. 5,180,210 shows a tool having at one end a chisel 64 (Fig. 1) comprising a part 65 aligned and connected to a piston and a point 68 which is offset relative to the axis of the tool handle. The purpose of the offset is to create enough working room for the tool.
Moreover, the technique involved is one of cold chiselling, the purpose of which is not to provide a lever effect since this would risk damaging the chute due to the shape of the point of the tool which is in the form of a chisel as opposed to a wedge.
U.S. Patent 4,871,214 describes a tool for dislodging unstable rocks in mines.
The principle consists of freeing the unstable rocks by vibrating them with the specially designed head 11 (Fig. 2) of the tool having the shape of a torus. With this method, the unstable rock will become looser and looser until it eventually falls. The tool has no levering capability.

U.S. Patent No. 3,619,009 shows an L-shaped curved tool point 13 of another type of scaling tool. The curve facilitates the operator's work in inserting the tool point into the cracks in the rock. However, the lever effect is due to the human effort of the operator who must push on the handle of the tool to lift and free the pieces of unstable rock.
Moreover, the shape of the tool point provides no clearance to facilitate the penetrating and wedging action of the tool.

Objectives of the Invention The object of this invention is to provide a tool for scaling unstable rocks in the walls of underground mine passageways, allowing for an improvement over existing systems by facilitating the work and increasing the safety of the operators using the tool.
One objective of this invention is to provide a mechanized scaling tool that combines the axial and radial forces of the tool to mechanically generate a lever effect for the purpose of dislodging unstable rocks and that minimizes the bending effort of the operator.
A further objective of the invention is to provide an ergonomic scaler that is light and portable with improved use and handling, thus reducing the effort required by the operator while minimizing the risk of accidents related to the job itself.
A third objective is to provide a scaling tool that will enable the operator to carry out the scaling at a safe working distance and angle by adjusting the handle of the scaler to a suitable length for a given scaling job.
A fourth objective is to provide a scaler with means for deflecting rocks that are detached from the walls far away from the hands and feet of the operator, and to provide means of protection from the pneumatic hammer of the scaler, making the work even safer.
A fifth objective of the invention is to provide means for allowing the operator to control the starting and stopping of the scaler at any time, and to provide a system for handling the tool that is adaptable, flexible and easy to use.
A sixth objective of the invention is to provide a tool having a point that facilitates the positioning of the tool in cracks, thus increasing the effectiveness of the scaling operation.
A seventh objective is to provide means for reducing the vibrations transmitted by the scaler to the operator during the scaling operation and to provide a good grip along its entire length.
An eighth objective of the invention is to combine the angle of the back of the tool point and the angle of the inner face relative to the axis of the handle with the penetration point of the tool into a crack in such a way so as to mechanically form a lever action by the sole displacement of a piston between the point and back of the tool, which is circumferentially larger relative to the point of the tool, with the operator's arms allowing at most an immediate detachment of the unstable rock without any movement or shifting of his body.

Another general objective is to provide a portable (light-weight), mechanical (pneumatic) scaler that is telescopic and ergonomically designed, having a tool equipped with a point which generates a lever action without any bending effort by an operator, thus increasing the effectiveness and quality of scaling while minimizing the risk of accidents.
It is also a general objective to provide a scaler with means for powering on and off by the operator at any time, means for protecting the operator and the scaler itself, means for attenuating the vibrations transmitted to the operator by the scaler; means to facilitate the positioning of the tool point in the cracks in the rock and to provide a good hold over the entire length of the handle of the scaler.
Consequently, it is an objective to provide a tool equipped with a point consisting of (a) a rounded end having a first longitudinal axis which is parallel to a second axis passing through the handle of the scaler, (b) an angular shank with an outer side forming the convex back of the tool attached concavely to the point, such that the back forms a bearing angle between either the axis of the angular shank or a straight line passing through two points, one on the concave part and one on the convex part of the angular shank, and the axis of the tool handle, and with an inner side forming the front of the tool or inner bearing surface, having a convex part attached to the point, followed by a concave part, such that the front forms a clearance angle between a straight line passing through two points, one on the convex part and one on the concave part of the front, and the axis of the tool handle, the bearing angle being greater than the clearance angle, and (c) attached to the angular shank, an S-shaped curved portion having a third axis, in the middle, forming an angle with the axis of the tool handle greater than 90 .

Brief Description of the Drawi"s Following is a detailed description, which is an indication and is in no way exhaustive, of the mechanisms corresponding to this invention, in particular with reference to the attached drawing, on which:

Figure 1 is a view of an operator using the tool;
Figure 2 is a side view of the tool point;

Figure 3 is a side view of the entire tool;

Figure 4 is a cross-sectional view of the tool and of the pneumatic motor element;
Figure 5 is a view of part of the point of the tool;

Figure 6 is a detailed view of the point of the tool in action.
Description of the Invention The preferred embodiinent of the invention is illustrated in Figure 1 in which the same characteristic elements are identified by the saine numbers, and in which we see the rock 20 with numerous unstable blocks 22. An operator 24 is freeing an unstable piece of rock 26 with a meclianized scaler 28 consisting of an impact mechanism 30 acting on a tool 32. The impact mechanism is connected to a telescopic handle 34 equipped with a control 36, and the handle 34 is connected to a compressed air source through a hose 38. A connection such as a ball joint. 40 joins the handle 34 to the hose 38 and a guard 42 protects the operator's hand.

The scaler is equipped with a reverse-curved tool 32 (Fig. 2) having a penetration point 44 offset from and parallel to a first longitudinal axis 46 of the tool handle, the penetration point having a second longitudinal axis 114. an angular shank 48 possessing a third axis 50. a lengtlt 52 and two sides; an elongated S-shaped portion 54 of which the central section is at about 45 relative to the first longitudinal axis 46; an anvil 56 (Fig. 3) with an elongated body 58 equipped with a stop 59;
and two ends 60 and 62. The end 62 (Fig. 4) of the anvil 56 is inserted in the upper part 64 of the main adaptor 66 as far as the open space 68 of a pneumatic hammer 70. The tool 32 is held by a lock half washer 72, a lock washer 74. a retaining ring 76, an absorbent bushing 78, a rubber accordion cover and bolts 80. The elongated body 58 of the tool 32 is encircled by a wearing ririg 82.

The pnetunatic hammer 70 that is placed inside the main adaptor 66 is intended to act on the anvi156 and has a piston stroke approximately four times longer than the displacement of the angular shank. The pneumatic hammer 70 is held fitted into the main adaptor 66 by means of a tightening yoke 84 which presses it against an inner buslling 86. A guard ring 42 welded to the hai-idle 34 joins the main adaptor 66 to the handle 34 witli lock bolts 90. The handle 34 consists of a sliding outer tube or telescopic sleeve 92 with a locking mechanism 94 comprising a screw ring 96, a support ring 98 and a conical flexible rubber piece 100 gripping an inner tube 102. The inner tube 102 is connected to a pneumatic control 104, with a trigger 106, by an installation ring 108 and a lock ring 110.
A ball joint 40 joins the lower end (Fig. 1) of the handle 34 to a compressed air tank through a hose 38. The ball joint 40 that is used may either be a single-action or double-action ball joint.
The tool 32 (Fig. 5) is equipped with a point 44 consisting of a rounded end 1.12 having a longitudinal axis 114 which is offset and parallel to the first longitudinal axis 46 passing through the liandle of the scaler. The offset distance between the axes is between 0.75 and 1.25 cm. The angular shank 48 has an outer side forming the convex back 116 of the tool which is attached concavely 118 to the point 44 such that the back fornls a bearing angle a between either the third axis 50 or a straight line passing through two points 122 and 124, on the concave part 118 and the convex back 116 respectively, of the angular shank 48, and the axis 46 of the tool handle.
The bearing angle is in the range of 5 to 30 . with a preferred range being 8 to 16 , and most preferably having a value around 15 . The bearing angle can be determined using either the straight line 120 (Fig. 5) or the third axis 50 since these lines should be considered as being essentially parallel. The angular shank 48 has an inner side forming a concave face 126 of the tool, or the inner bearing surface, having a short convex part 128 attached to the point 44 followed by a concave portion 130 such that the face 126 forms a clearance angle (3 between a straight line passing through points 132 and 134 on the convex part 128 and the concave portion 130 respectively on the front 126, and the axis 46 of the tool handle. The clearance angle (3 is in the range of 0 to 12 . preferably about 4 . The bearing angle a being larger than the clearance angle (3 causes a widening of the angular shank 48 which results in a wedging action. the convex back 116 acting as a wedge and the concave portion 130 offering a clearance. The concave portion 130 of the face126 corresponds to the convexity 116 which is followed by an S-shaped portion 54 having a third axis 136. The third axis 136 forms an angle -t that is ,treater than 90 , preferably near 135 . with the axis 46 that passes through the tool handle bringing the S-shaped portion 54 into the axis 46 of the tool handle.

In summary, the scaling tool 32 (Fig. 1) for the removing of unstable rocks comprises:

- an anvil 56 (Fig. 3) comprising an elongated body 58 along a first longitudinal axis 46 and two extremities. the elongated body intended to be displaced longitudinally;
- a penetration portion 33 (Fig. 2) comprising a penetration point 44, an angular shank 48 and an S-shaped portion 54. the penetration point 44 having a longitudinal axis 114 and two ends, the angular shank having a second longitudinal axis 50, length 52 and two sides the S-shaped portion being elongated;

- means for periodic displacement acting on the anvil 56;
- the first extremity 112 (Fig. 5) of the penetration point being directed axially 114 toward the unstable rocks, the second extremity I 13 being joined at a first angle a in a concave manner 118 to the angular shank 48, a first surface of the stem substantially forming a convex back 116 acting as a wedge relatively to the longitudinal axis 114, and a second surface forming a concave face 126 w-hich is directed toward the first longitudinal axis 46 at an angle (3, where angle (3 is smaller than angle a; the angular shank being extended by t;le S-shaped portion 54 to the first end 60 of the anvil 56 (Fig. 4), while the second end 62 of the anvil is a nieans to receive an axial displacement of the anvil such that the anvil, tlae S-shaped portion, the angular shank and the tip point causes penetration between the rocks and the lever action removing the rocks.

The displacement of the anvil corresponds to a range of axial displacements of 20 to 35% of the displacement of the mechanical hammer and the radial displacement on the angular shank 48 corresponds to a range of 25 to 40% of the axial displacement of the anvil.
The radial displacement relative to the free end of the tool point produces a lever effect.

During the scaling operation. an operator first visually searches the walls of a mine passageway to detect the cracks of unstable rocks. He (or she) then inserts the point 44 (Fig. 6) of the tool 32 into a crack and activates the scaler by means of the trigger 106 (Fig. 4) of the pneumatic control 104 while siniultaneously applying a pushing effort along the axis 46 of the tool without making any of the bending effort which would be necessary with a tool having a wedpTe point and no clearance.

The lever effect is produced by the reverse-curve of the tool point, and increases as the tool 32 (Fig. 6) penetrates into a crack 138. In position 1, illustrated in continuous lines. the concave face or inner bearing surface 126 of the too132 pushes against a piece of unstable rock 140 while the back 116 presses 142 against the rock face 144. Because of the hammering action, the angular shank 48 penetrates into the crack 138, while the back 116 remains pressed 142 against the sanie place (or nearly so) on the rock 144. The clearance angle (3 (Fig. 5) facilitates the penetration of the angular shank 48, while the bearing angle a of the back 116 generates a moment acting on the unstable rock 140 (Fig. 6) caused by the lateral displacement 146 of the longitudinal axis 46 of the tool handle toward the unstable rock 140, putting the rock into position 2 shown in long dashes. The hammering then pushes the angular shank 48 of the tool 32 further into the crack 138.
while the back 116 still remains pressed against the same place 142, increasing the size of the moment throuoh the action of angle a of the back 116 and finally freeing the unstable rock, as in position 3, shown in short dashes. tlltimately, the unstable rock is dislodged and falls to the ground.
If the rock should slide along the tool as it drops. the protective ring 42 (Fig. 1) will deflect it far from the operator's hands and feet.

Let us analyze the lever effect generated by the scaling tool 32 (Fig. 2) against -the unstable rock. Two penetration cases are described to better present what proportion of the axial (pushing) force of the tool and of the operator is radially transmitted to the unstable rock.

CASE 1:

Point 148 to 150: horizontal displacement of the scaling tool 32 caused by the impact on the anvil 33 by the stroke of the piston of the pneumatic hammer Point 148 to 152: corresponding displacement along the back 116 of the tool 32 Point 152 to 150: corresponding vertical displacement (push) of the tool 32 Accordingly, to scale, if the segnient 152 to 150 measures 0.55 inches. and the segment 148 to 150 measures 2 inches, for an axial displacement of about 2 inches, there is a radial displacement of:

0.55/2=0.275or27.5%
CASE 2:

Point 148 to 154: horizontal displacement of I inch Point 148 to 156: radial displacement Point 156 to 154: vertical displacement of 0.375 inches that is 0.375/1 =
0.375 or 37. %

With one of the specifications for the pneumatic hammer being that its piston should have a diameter D = 0.787 inches and that the air pressure P (used in mines) should be between 80 and 90 psi, the pushing force Fp of the scaler hammer can be approximated by multiplying; the area Ap of the piston by the pressure P of the air supply:
Fl, = P x Ap = P xTu(D')/4 = 43.78 lbs, where P = 90 psi Assuming a reasonable pushing force by the operator of about 60lbs, combined with that of the 1lanuner. one can estimate the total puslling force Fr to be around 1001bs.

Considering Case 2, when the scaler is activated in practice, part of the piston stroke is transmitted to the scaler by rebound and the other part, around 25% to 50%, contributes to the penetration of the tool point into a crack in the rock. Therefore, the force applied to one side of an unstable i-ock, according to Case 2, would be:
37.5% x 100 lbs = 37.5 lbs Considering a pivot forming a lever at a typical distance of 5 to 6 inclles perpendicular to the line of action of the force of 37.5 lbs, we can estimate an order of magnitude for the moment generated on the unstable rock as follows:
37.5 lbs x 5.5 inches = 206.25 lbs=in This moment, which is on the order of 200 Ibs=in, is comparable to the one that must be generated by operators using nianual scaling tools. This requires a bending effort by the operators, often at the end of their reach or in a tiring or uncomfortable position. With the present invention, the operator only provides an axial pushing force of about 60 lbs relative to the axis 46 of the tool handle in an ideal and ergonomic position (Fig. 1). Thus, it is the shape of the convex back 116 (Fig. 5) of the scaling tool 32 that generates a moment against the unstable rock without any bending effort from the operator. The concave portion 130 and the clearance angle (3 facilitate the penetration while the displacement 146 (Fig. 6) and the widening of the angular shank increase the force against the wall 142 of the rock and against the unstable piece of rock 140. The elongated S-shaped porlion 54 (Fig.
2) follows the angular shank 48 and forces the unstable rock to dislodge itself by sliding over the inner surface 158 (Fig. 6) as the scaling tool 32 advances into the crack.
Thus, the combination of angle a(Fig. 5) of the back of the tool point and angle (3 of the inner face relative to the handle axis with the penetration of the too132 in a crack creates a lever effect solely by the displacement of a piston between the point 44 and the back of the tool 116, circumferentially relative to the end 112 of the point 44 of the tool, the operator's arms allowing at most an immediate dislodging of the unstable rocks without any movement or shifting of the operator's body.

Other Potential Embodiments The combined effects of the inner bushing 86 and the absorbent bushing 78 minimize the vibrations transmitted to the operator by the scaler, protecting the back-and-forth movements of the hammer. As well, the telescoping sleeve 92 and the screw ring 96 are knurled along their entire length, improving the operator's grip on the tool regardless of the position of his hands on the sleeve.
It must be clearly understood that the form ofthe embodiment ofthis invention, described above in reference to the attached drawings, has been provided as an indication and is in no way exhaustive, and that modifications or adaptations can be made without departing from the scope of this invention.
Other embodiments are possible and are limited only by the scope of the claims that follow.

Claims (21)

1. A scaling tool for the dislodging of unstable rocks in underground mines, said scaling tool comprising an anvil and a penetrating portion generally in line along a common axis, said anvil being adapted to be hit by periodic displacement means acting on said anvil along said common axis and said penetrating portion being joined to said anvil, said anvil comprising:
a generally circular elongated body with a first longitudinal axis, a hit end to receive an impact from said periodic displacement means, a junction end to connect to said penetrating portion, said penetrating portion comprising:
a penetration point being disposed along a second longitudinal axis, said second longitudinal axis being parallel to said first longitudinal axis and laid at a distance from said first longitudinal axis said penetration point having a free end, an angular shank being an extension of said penetration point in an opposing direction from said free end and comprising a third axis, a length and two sides, an S-shape at said junction end, said S-shape being also elongated, connecting said angular shank to said elongated body of said anvil at said junction end, said first and third axes forming an angle a between each other, a first side of said shank forming a convex back, adapted to form a wedge with said second longitudinal axis and a second side forming a concave face oriented toward said first longitudinal axis and forming a clearance angle .beta. and where said angle .beta. is smaller than said angle .alpha., the angle .alpha. may alternatively be formed by said first axis and a straight line passing through a convex point and a concave point along the back of said angular shank; the axial displacement of the elongated body of the anvil, the S-shape, the angular shank and the penetration point, when hit by said periodic displacement means, causing penetration between rocks and the forming of a lever for the dislodging of said rocks.

2. A scaling tool as defined in claim 1 wherein the value of angle .alpha.
between said angular shank third axis and said second longitudinal axis lies in a range 5°
to 30°.

3. A scaling tool as defined in claim 2 wherein the value of angle .alpha.
lies in the range 5° to 25°.

4. A scaling tool as defined in claim 2 wherein the value of angle .alpha.
lies in the range 10° to 30°.

5. A scaling tool as defined in claim 2 in which the preferred range of values of the angle .alpha. is 8° to 16°.

6. A scaling tool as defined in claim 1 where the preferred range of values of clearance angle .beta. is between 0° and 12°.

7. A scaling tool as defined in claim 1 of which the means of periodic displacement consists of a mechanical hammer.

8. A scaling tool as defined in claim 7 wherein said periodic displacement means comprises a mechanical hammer, provided with a piston adapted to be displaced axially toward said anvil onto said hit end, said scaling tool further comprising:
an envelope forming a primary adaptor adapted to receive said pneumatic hammer and said hit end, a fixed exterior handle attached to said primary adaptor, a hollow inner telescopic sleeve, sliding within said fixed exterior handle, comprising means for passage of a fluid channelled to act on said hammer and means adapted to said handle to initialize the flow of said fluid.

9. A scaling tool as defined in claim 8 wherein the displacement of the anvil corresponds to a range of axial displacements of 20 to 35% of the displacement of said mechanical hammer and the radial displacement on said angular shank corresponds to a range of 25 to 40% of said axial displacement of the anvil, said radial displacement relative to said free end producing a lever.

10. A scaling tool as defined in claim 9 wherein said mechanical hammer is pneumatic and said piston has a stoke approximately four (4) times longer than the displacement of said anvil.

11. A scaling tool as defined in claim 8 comprising a pneumatic control comprising a trigger, for the starting and stopping of said mechanical hammer and installed on an inferior portion of said inner telescopic sleeve.

12. A scaling tool as defined in claim 8 including a fixed exterior handle receiving a sliding inner telescopic sleeve, further comprising a locking mechanism.

13. A scaling tool as defined in claim 8 comprising a fixed exterior handle receiving a sliding inner telescopic sleeve and comprising a locking mechanism installed along the central portion of said inner telescopic sleeve and comprising a screw ring, a plastic support ring and a conical rubber piece.

14. A scaling tool as defined in claim 8 including an accordion-mounted rubber covering of which one end is fixed at the end of said main envelope and the other end adheres to said elongated body and which is intended to allow movement while maintaining a means of protecting the sliding surface.

15. A scaling tool as defined in claim 8 wherein said envelope comprises means for retaining said scaling tool consisting of a lock half-washer, a lock washer, a retaining ring, an absorbent bushing, a rubber accordion cover and bolts.

16. A scaling tool as defined in claim 8 wherein said pneumatic hammer comprises a telescopic handle fastened to said primary adaptor with a tightening yoke that presses said primary adaptor against an interior bushing onto which is fixed a guard ring, thereby connecting the primary adaptor and the telescopic handle by means of lock bolts.

17. A scaling tool as defined in claim 8 including an absorbent bushing inserted on the retainer stop of the shank at the end of the main envelope of the hammer, and also including an inner bushing of the envelope placed next to a protective ring and located between the lower end of the adaptor and the said pneumatic hammer.

18. A scaling tool as defined in claim 8 wherein the telescoping sleeve and the screw ring are knurled along their entire length.

19. A scaling tool for the detachment of unstable rocks in underground mines as defined in claim 10 in which the means of connecting a source of compressed air to the said tool in a functional and rapid manner includes a single-action or double action ball joint.

20. A scaling tool as defined in claim 8 in which the means of generating a lever effect includes the use of a reverse-curved tool of which the second longitudinal axis is offset and parallel to the axis of the tool handle.

21. A scaling tool as defined in claim 20 wherein said distance between said first longitudinal axis and said second longitudinal axis falls in a range between 0.75 and 1.25 cm.