273 results about "Chisel" patented technology

The invention discloses a protective device for safety of mining machinery, and relates to the technical field of mining equipment, in particular to a protective device for safety of mining machinery, which comprises a base, a rotating frame, a protective component and a supporting component, and a plurality of iron chisels used for being inserted underground are fixedly mounted on the lower surface of the base; the lower end of the rotating frame is hinged to one end of the base; and through the combination of multi-stage damping and elastic buffering, the absorption capacity to large impact force is greatly improved. When the impact force continuously acts to cause the first piston plate to move to a set distance, the distance sensor transmits a signal to the control panel, and the control panel starts the electromagnet, so that the magnetic particles in the magnetorheological fluid are orderly arranged in a solid-like state, the position of the piston assembly is locked, excessive rotation of the rotating frame is avoided, and the service life of the rotating frame is prolonged. Compared with a locking block clamping structure of an existing device, the locking block clamping structure has higher fixing reliability, the situation that the structure loses efficacy due to continuous impact is effectively prevented, and safety of mining machinery is guaranteed.

A pry bar assembly includes a plate that is elongated and has a first end, a second end, a first lateral edge, a second lateral edge, an upper surface and a lower surface. The plate includes a claw section, a chisel section and a middle section positioned therebetween. The claw section includes the first end and a rounded heel. The claw section includes a first portion and a second portion. The first portion is attached to the middle section and curves upwardly and away from the middle section in a semi-cylindrical shape to form the rounded heel. The second portion extends downwardly from the first portion. The chisel section is angled upwardly from the middle section. The upper surface has an elongated crest therein that is spaced from the first and second lateral edges and extends along a length of the middle section and into the chisel section.

1. Name of the designed product: chisel plane. 2. Use of the designed product: for chiseling wood. 3. Design points of the designed product: in shape. 4. Picture or photo best indicating the design points: perspective view 1.

This invention discloses a drill bit for preventing delamination, detachment, and burr defects, belonging to the field of cutting tool technology. The invention mainly consists of a shank, a drill core, and an outer portion of the drill bit; the drill core is higher than the outer portion; the end structure of the drill bit is flower-shaped. The drill core has two axially symmetrically distributed cutting sections. The outer portion of the drill bit mainly consists of a second rake face, a second primary flank face, a second secondary flank face, and a third secondary flank face. The drill bit employs a double primary cutting edge. The drill core uses a small-angle peak and a short chisel edge to improve its self-centering and chip removal functions, reducing axial cutting force; the outer portion of the drill bit uses a negative peak, forming a concave structure, which generates a centripetal radial cutting force during machining. Through the cooperation between the first primary cutting edge of the drill core and the second primary cutting edge of the outer portion of the drill bit, the axial cutting force is reduced, cutting away material containing defects from the hole wall instead of pushing it towards the hole wall, effectively suppressing the formation of delamination, detachment, and burr defects.

The invention relates to a drop hammer impact equivalent test device capable of reproducing an ultra-high-speed chipping damage effect. The problem that a low-cost test device for chipping damage effect and protection technology research is lacked at present is solved. Comprising an impact test platform, an overall frame, a guide rail, a multifunctional drop hammer, a heating device, a hammer grabbing and disengaging device and a lifting device, the overall frame is fixed to the impact test platform, the guide rail is vertically installed on the overall frame, the lifting device is installed on the top of the overall frame, and the multifunctional drop hammer is detachably connected to the lower portion of the lifting device and matched with the guide rail. The heating device is mounted on the multifunctional drop hammer, the multifunctional drop hammer is provided with a positive impact test hammer head and an inclined impact test hammer head, the slide rail sample is fixed on the impact test platform during a positive impact test, and the slide rail sample is obliquely fixed between the impact test platform and the integral frame during an inclined impact test. According to the method, the chipping damage effect can be effectively reproduced, and the method has important engineering value for material damage mechanism and protection technology research.

The utility model discloses a soil radon concentration detection punching limiting tool which comprises a steel chisel body, a plurality of height marking lines are arranged on the outer side wall of the steel chisel body, a holding piece is arranged at the top of the steel chisel body through a fastening device, and the fastening device comprises a fastening threaded rod arranged on the holding piece. A threaded hole in threaded connection with the fastening threaded rod is formed in the top end of the steel chisel body, and a locking assembly is further arranged between the fastening threaded rod and the threaded hole. On one hand, the punching depth can be conveniently controlled, so that the punching depth meets the standard requirement; on the other hand, the steel chisel body can be easily inserted into soil through the holding piece, so that the punching effect is achieved; and after punching to the required depth, the steel chisel main body is pulled out by holding the holding piece and rotating upwards, so that punching and pulling-out are easier and faster, detection data are more reliable and accurate, and the problems that the soil radon concentration detection punched hole is difficult to insert and pull out, the punching depth is difficult to determine, and the detection efficiency and accuracy are influenced are solved.

The invention relates to a base (10) for accommodating a chisel holder (30), comprising a main body (13) which has a holder seat (14) for accommodating the chisel holder (30), the holder seat (14) having: a socket (18); at least one front supporting surface (15.1, 15.2), which is located at least partially in front of and / or to the side of the socket (18); and at least one rear supporting surface (16.1, 16.2), which is located at least partially behind the socket (18). In order to ensure that a chisel holder (30) mounted in the base (10) remains securely fastened even under exceptionally high loads, according to the invention, the main body (13) has two clamping surfaces (18.5, 18.6) of a rear overload support section (18.4) in the insertion area that leads into the socket (18), each clamping surface (18.5, 18.6) facing a side of the main body (13).

The invention belongs to the technical field of drilling tools, and discloses a coating drilling tool and a machining method.The coating drilling tool comprises a drill tip part, the drill tip part comprises a front tool face and two tool end faces, the two tool end faces intersect to form a chisel edge, each tool end face comprises a first rear tool face, and the first rear tool faces intersect with the front tool face to form a main cutting edge; the drill tip part further comprises a first machining area, the first machining area is arranged on the front tool face and intersects with the main cutting edge, a first micro-texture is arranged in the first machining area, and / or the drill tip part further comprises a second machining area, the second machining area is arranged on the first rear tool face and intersects with the chisel edge and the main cutting edge, and a second micro-texture is arranged in the second machining area. A second microstructure is arranged in the second machining area. The first microtextures and the second microtextures can improve the surface roughness of the front tool face and the first rear tool face, improve the coating binding force, slow down tool abrasion, improve the cutting performance and reduce abrasive particle abrasion and bonding abrasion between interfaces.

This application discloses a quick-change steel chisel, relating to the field of steel chisel technology. The application includes a chisel head, one end of which is fixed to a support block. A connector post is fixed to the end of the support block away from the chisel head. A handle is provided at the end of the connector post away from the support block. A connecting post is fixed to the end of the handle near the connector post. A connector groove is formed on the connecting post, and the connector post is slidably disposed within the connector groove. A fixing structure is provided between the connector post and the connecting post. This fixing structure allows for quick fixing of the chisel head and handle, and disassembly is relatively convenient, enabling rapid chisel head replacement, significantly improving work efficiency. The connection is also effective, preventing easy loosening or detachment. Furthermore, the operation is simple, requiring no additional tools to replace the chisel head.

A power tool adapted to impart axial impacts to a tool bit includes a housing having a motor housing portion and a handle portion extending transversely from the motor housing portion, an electric motor supported in the motor housing portion and defining a motor axis, a non-rotatable barrel extending from the motor housing portion and defining a barrel axis parallel to the motor axis, a reciprocation drive assembly coupled to the electric motor and configured to convert torque from the electric motor to reciprocating motion of a piston received within the barrel for reciprocation therein along the barrel axis, a striker received within the barrel for reciprocation in response to the reciprocation of the piston, and an anvil at least partially received within the barrel and positioned between the striker and tool bit.The anvil communicates axial impacts to the tool bit in response to reciprocation of the striker.

1. The name of the design product: light hammer (26). 2. The use of the design product: the design product is used for hammer, chisel, drilling and other operations. 3. The design points of the design product: in shape. 4. The picture or photo that best shows the design points: design 1 perspective view. 5. Design 1 is designated as the basic design.

A surgical instrument for the revision of prostheses, comprising a handpiece in which a cylinder is arranged, wherein a piston element is associated with the cylinder, as well as a switching element and a chisel tool, wherein the chisel tool is arranged axially movably mounted at one end of the handpiece, wherein the chisel tool is fastened to the handpiece in a loss-proof manner, wherein the piston element is axially movably arranged in the cylinder, wherein the piston element can be set in motion by means of a fluid, wherein the piston element is configured to induce a pulse directed in the direction of the chisel tool for driving the chisel tool into a prosthesis stem interspace associated with the prosthesis, wherein the piston element is configured to induce a pulse, directed opposite to the chisel tool for driving the chisel tool out of the prosthesis stem interspace.

The utility model relates to the technical field of geological survey, and discloses a knocking hammer for mineral resource geological survey, which comprises a splicing assembly, the splicing assembly comprises a hammer head, a limiting groove is arranged on one side of the hammer head, the limiting groove is connected with a limiting block, the limiting block is connected with a balancing weight, the balancing weight is connected with a bolt, and the bolt is connected with a nut. The lower end of the hammer head is connected with a threaded connecting column, the lower end of the threaded connecting column is connected with a chisel head, one side of the hammer head is connected with a connecting shaft, one end of the connecting shaft is connected with a first hammer handle, and the outer ring of the first hammer handle is connected with a rubber pad. According to the utility model, the resistance of rocks can be overcome more quickly during knocking, the same crushing effect can be achieved by reducing the knocking times, the time can be saved and the working efficiency can be improved in geological survey, and the hammer head can obtain higher linear speed and kinetic energy under the condition of applying the same force, so that the knocking force is enhanced, and the service life of the hammer head is prolonged. And the rock sample can be crushed more effectively.

The invention relates to a chisel holder (30) for a soil cultivation machine, in particular for a road milling machine, a stabilizer, a recycler, or a surface miner, with a support body (35) which has a chisel receptacle (32) in the area of ​​a working side or at least carries a cutting tip, wherein the support body (35) indirectly or directly carries a plug socket (44) on a plug socket side, wherein the plug socket (44) has a plug socket longitudinal axis (44.2), wherein the plug socket longitudinal axis (44.2) lies in a central longitudinal plane (ME) of the chisel holder (30), wherein the support body (35) has two front planar cutting surfaces (41.1, 41.2) forming a pair of cutting surfaces, which are angled to each other such that they enclose a transverse support angle (α), and which are arranged in a region in front of the plug socket (44), wherein the front cutting surfaces (41.1, 41.2) extend laterally from the plug-in end (44) towards the rear of the chisel holder (30) beyond the plug-in end longitudinal axis (44.2) of the plug-in end (44), and wherein the support body (35) has at least one rear cutting surface (43.1, 43.2) which forms an obtuse longitudinal support angle (β) with at least one of the front cutting surfaces (41.1, 41.2) and which is arranged at least partially behind the plug-in end (44). In order to achieve improved follow-through behavior with such a chisel holder compared to a base on which the chisel holder is mounted, it is provided that the front cutting surfaces (41.1, 41.2) transition laterally to the plug-in end (44) via at least one inclined surface (42.1) directly or indirectly into the rear cutting surface (43.1, 43.2) or into a rear cutting surface (43.1, 43.2).

The invention belongs to the technical field of liquid cooling servers, and particularly discloses a shoveling tooth cold head which comprises a heat exchange plate, heat exchange teeth formed by gear shaping are arranged at the top of the heat exchange plate, and the heat exchange teeth are distributed in a rectangular array; machining equipment for a shoveling tooth cold head comprises a base, a liquid storage cavity is formed in the base, a recycling cavity is formed in the top of the base, and filtering holes which are evenly distributed and communicate with the liquid storage cavity are formed in the inner wall of the recycling cavity; by arranging the shoveling tooth cold head, a flow channel formed by heat exchange teeth of the shoveling tooth cold head is wider, blockage can be effectively prevented, the strength of the teeth is far higher than that of tooth pieces, deformation can be prevented, transportation is convenient, the problem that traditional tooth pieces are prone to deformation in the transportation process is solved, the flow channel is wider, internal passivation treatment is better facilitated, cleaning is facilitated, and the service life of the shoveling tooth cold head is prolonged. And the heat exchange teeth can be machined by adopting a gear shaping process, so that the machining efficiency is improved.

The present application discloses a pneumatic chipping hammer, and relates to a pneumatic impact tool, which comprises a handle part, the handle part being a hollow member; a main power part, one end of the main power part being connected to the handle part, and principal axes of the handle part and the main power part forming a certain angle; and a chisel part, the chisel part being detachably connected to the other end of the main power part, wherein the direction of mounting the chisel part on the main power part can be changed. According to the pneumatic chipping hammer of the present application, the mounting direction of the chisel part on the main power part is changed by the locking member, and therefore the angle between the principal axes of the handle part and the main power part can be 5-85 degrees, so that a handle is inclined to further achieve different purposes and be suitable for people with different heights.

The invention relates to the technical field of assembly type box body walls, in particular to a prefabricated assembly box body ecological retaining wall which comprises a main body assembly which comprises a retaining wall body, a vertically-chiseled sculpture fixing hole and a hoisting opening. The fixing assembly comprises an inner concave table and a butt joint table arranged on the inner wall of the inner concave table; the inner wall of the outer boss is provided with a built-in cavity, the inner wall of the built-in cavity is provided with a built-in plate, and the end face of the built-in plate is provided with an inner locking piece. Through inclined plane matching of an outer boss and an inner concave table and accurate alignment of a butt joint sleeve and a limiting sleeve, a traditional manual measurement and adjustment mode is replaced, the positioning time of a single retaining wall is greatly shortened, and upper and lower layer dislocation caused by manual errors is avoided; and meanwhile, the inner locking piece is integrated in the inner cavity of the outer boss, an external supporting piece does not need to be additionally arranged, construction procedures are reduced, the surface space of the retaining wall body is not occupied, vertical chiseling sculptures are prevented from being shielded, a complete space is reserved for subsequent ecological functions, and the assembling efficiency and ecological adaptability are both considered.

The drilling cutter is applied to the field of machining and comprises a cutter handle, a cutter body is arranged at one end of the cutter handle, a drill tip is arranged at the end, away from the cutter handle, of the cutter body, a main cutting edge, an end edge and a chisel edge are arranged on the drill tip, and a G-shaped chip containing groove is formed in the drill tip. The drilling tool has the technical effects that in the machining process of the drilling tool, the drill tip plays a key centering role, the positive rake angle is formed at the drill tip through the design of the G-shaped chip containing groove, and as the linear speed at the absolute center of the drill tip is zero, when the drill tip is just in contact with a part, extrusion caused by machining has great damage to a drill core of the drill tip; the positive rake angle can play a cutting role when the main cutting edge drills, independent chip breaking is completed in the G-shaped chip containing groove, meanwhile, the sharpness of the chisel edge is enhanced, drill core abrasion of the drill tip is relieved, the service life of a cutter is prolonged, and the drilling efficiency and the production quality are improved.

The application relates to the field of EMU (Electric Multiple Unit) operation of railway inter-route transportation, and particularly relates to a multi-purpose EMU chisel rod. The multi-purpose EMU chisel rod comprises a supporting rod and a working head fixedly installed on the supporting rod, the working head comprises a vertical middle rod and horizontal rods and barbed rods arranged on both sides of the middle rod respectively, the upper end of the middle rod is a pointed head, one end of the horizontal rod is fixedly connected to the middle part of the middle rod, and the horizontal rod is arranged perpendicularly to the supporting rod, one end of the barbed rod is fixedly connected to the middle rod and located above the horizontal rod, the barbed rod is arranged obliquely from top to bottom from the connecting part with the middle rod, and the free end of the barbed rod is a pointed head structure. The multi-purpose EMU chisel rod provided by the application has a good foreign matter removing effect.

A milling head (1) having a rotation axis (x) is used for machining the head (80) of a pile (8), the pile including a pile core (81), a pile sleeve (82), and a metal armor (83) inserted between the two. The milling head includes: a coupling device (13) connectable to a drive shaft (2) of a drive unit; a center milling cutter (11) including a plurality of center chisels (111) mounted on the underside of an inner ring plate (112); and an annular milling cutter (12) including a plurality of annular chisels (121) mounted on the underside of an outer ring plate (122). The center milling cutter (11) and the annular milling cutter (12) are connected to each other coaxially aligned with the rotation axis (x), and the outer ring plate (122) surrounds the inner ring plate (112), while the inner ring plate (112) and the outer ring plate (122) are separated by an intermediate annular region (kr2). According to the invention, the inner ring plate (112) includes at least one conveying opening (1120A, 1120B) extending from the lower side of the inner ring plate (112) to the upper side of the inner ring plate (112), the conveying opening (1120A, 1120B) being adjacent on the lower side to a conveying shovel (119A, 119B) that extends at least partially into the working area of ​​the central chisel (111), and the conveying opening (1120A, 1120B) being adjacent on the upper side to a screw conveyor (113A, 113B).

The utility model relates to the technical field of detection instruments, and particularly discloses a digital display steel chisel penetration instrument which comprises a steel chisel guide pipe, a base and a top plane, the lower end of the steel chisel guide pipe is fixedly connected to the upper end of the top plane, the lower end of the top plane is fixedly connected with the base through three supporting rods, and a steel chisel is arranged in the steel chisel guide pipe; a supporting frame is fixedly arranged at the upper end of the top plane, a rotating shaft is rotationally arranged on the supporting frame, a distance measuring rotating plate is fixedly arranged at one end of the rotating shaft, a coding distance measuring roller is fixedly arranged at the other end of the distance measuring rotating plate, a coding wheel testing hole is formed in the steel chisel guide pipe, and one side of the coding distance measuring roller is located in the coding wheel testing hole. The side, close to the coding wheel testing hole, of the coding distance measuring roller makes contact with the steel chisel. According to the utility model, the insertion depth of the steel chisel can be automatically recorded, the precision is higher, the descending height and inclination of the steel chisel are more accurately controlled, and the impact energy is more standard.

The invention relates to a chisel holder (30) for a soil cultivation machine, in particular for a road milling machine, a stabilizer, a recycler, or a surface miner, with a support body (35) which has a chisel receptacle (32) in the area of ​​a working side or at least carries a cutting tip, wherein the support body (35) indirectly or directly carries a plug socket (44) on a plug socket side, wherein the plug socket (44) has a plug socket longitudinal axis (44.2), wherein the plug socket longitudinal axis (44.2) lies in a central longitudinal plane (ME) of the chisel holder (30), wherein the support body (35) has two front cutting surfaces (41.1, 41.2) forming a cutting surface pair.2) having, which are at an angle to each other such that they enclose a transverse support angle (α) and which are arranged at least partially in front of the plug-in end (44), wherein the plug-in end (44) has at least one convex front shank contact surface (45) on its front side, and wherein a cutting surface (SF) running parallel and at a distance from the central longitudinal plane (ME) through the chisel holder (30) intersects one of the two front cutting surfaces (41.1, 41.2) of the cutting surface pair and the front shank contact surface (45). To improve the fastening of the chisel holder in a lower part, the invention provides that the front cutting edge (SK) of the removal surface (41.1, 41.2) and the front cutting edge (45.3) of the front shank contact surface (45) of the cutting surface (SF) enclose an undercut angle (γ), wherein this undercut angle (γ) is at least 103° and at most 114°.

The application provides a pneumatic impact quick-disconnecting fixing bolt breaking method and a breaking device thereof, and comprises the following steps: determining a target door body to be broken, and chiseling the four corners of the door frame outside the target door body; using a crowbar to flip the vertical door side strips on the left and right sides of the door frame; using a bolt detector to determine the positions of the fixing bolts in the door frame; using a pneumatic impact gun and a chisel to break the concrete near each fixing bolt to form a bolt breaking gap; replacing a crescent shovel working head to quickly disconnect each fixing bolt through each bolt breaking gap; and using a door body traction pulling device to pull out the target door body as a whole to complete the breaking. The application has no power limitation, further shortens the time required for breaking doors and windows, greatly improves the rescue efficiency, and is safe and reliable without power supply and with small action amplitude, and is suitable for special places such as explosion-proof, high-rise, narrow space and the like.

The utility model discloses a kind of super pry-proof lock boxes, comprising: door leaf and lockset, lockset is installed at the frame of door leaf, the lockset includes lock box main body and right-angle edge covering steel plate, right-angle edge covering steel plate completely covers lock box main body front surface, and one end of right-angle edge covering steel plate is butt-jointed with the frame of door leaf, and the side of lock box main body close to door leaf is wrapped up.The utility model is made of right-angle edge covering steel plate of high-strength steel material completely covers lock box main body front surface, and is tightly butt-jointed with door leaf frame, and the side of lock box main body close to door leaf is wrapped up, the structure is formed after the panel of door leaf is destroyed, forms firm physical barrier, effectively blocks the intrusion of pry bar, chisel and other tools outside, prevents attacker direct contact and destroys lock box main body inside lockset core component, such as pull block, motor, transmission mechanism etc.

The utility model belongs to the technical field of building construction equipment, and discloses a wall bushing chiseling tool which comprises a chiseling rod, one end of the chiseling rod is a connecting end, the other end of the chiseling rod is an operating end, the operating end is fixedly provided with a separating part and a cutting part, the separating part is provided with a separating slope, and the cutting part is provided with a wall breaking blade. In the penetrating direction of the sleeve, the step-by-step separation part is inserted into a joint of the sleeve and concrete, so that the separation slope can be gradually close to and abut against the outer wall of the sleeve, and the peripheral side of the sleeve is partially separated from the concrete under the prying action of the separation part; when the casing pipe is cut, the separating part is further inserted, so that the wall breaking blade cuts the side wall of the casing pipe in the penetrating direction of the casing pipe until the casing pipe is completely cut open, chiseling and dismantling of the casing pipe are completed, the separating part and the cutting part are matched with each other, time and labor are saved, operation efficiency is high, production cost is low, and universality is high.

The utility model relates to the technical field of steel chisels, and discloses a twisted steel chisel which comprises a core part and four metal steel wires wrapped on the outer wall of the core part and twisted in a spiral mode, the core part is a steel wire column, the metal steel wires are distributed on the outer wall of the steel wire column at equal intervals, the spiral twisting directions of the metal steel wires are opposite, and the spiral twisting directions of the metal steel wires are opposite. Gaps among the metal steel wires are coated with wear-resistant high polymer material layers so as to enhance the wear resistance of the whole structure, and the tail ends of the metal steel wires are connected with connecting blocks which are conical. Through the design of the plurality of metal steel wires, the steel fibers are more uniformly distributed in concrete, the anchoring property and cohesiveness with the concrete are enhanced, meanwhile, the connecting blocks are conical, and the surfaces of the connecting blocks are treated to form micron-order roughness, so that the binding force between the steel fibers and the concrete is further improved, and the service life of the steel fibers is prolonged. The fibers are effectively prevented from being pulled out under the action of external force, and the risk that the fibers are straightened to be loosened or pulled out in concrete is reduced.

The utility model relates to the technical field of machine manufacturing, and discloses a relieving tool mounted on CNC (computer numerical control) machining center equipment, which comprises an equipment lathe bed and an equipment spindle head, an equipment workbench capable of transversely and longitudinally moving is arranged on the equipment lathe bed, a third bolt is in threaded connection with the bottom of the equipment spindle head, and a fourth bolt is arranged on the third bolt. A positioning plate is in threaded connection with the outer portion of a third bolt, a supporting main bottom plate is in threaded connection with the outer portion of the third bolt, a rotating shaft seat is in threaded connection with the bottom of the supporting main bottom plate, a first rotating shaft is rotationally connected into a cutter fixing plate, and a scraper knife is in threaded connection with the top of the cutter fixing plate. According to the tool fixing device, the positioning plate is fixed to the equipment spindle head through the third bolt, meanwhile, the angle of the tool fixing plate is adjusted through the rotating shaft base and the rotating shaft, and after adjustment is completed, the tool fixing plate is fixed through the vertical plates on the two sides and the first bolt, so that the stability of equipment is kept when the equipment runs, and the precision of relieved tooth machining is guaranteed.

The utility model discloses a slat wall chiseling mechanism which comprises a center frame above the ground. A downward electric impact device is arranged at the front end of the center frame, and different types of chiseling heads can be replaced by interfaces of the electric impact device; a transverse frame with the two ends transversely extending out of the center frame is arranged on the upper side of the center frame, limiting plates capable of moving along the transverse frame and being locked are arranged on the two sides of the center frame on the transverse frame, the limiting plates are vertical and located on the lower side of the transverse frame, edge wheels are arranged on the inner sides of the limiting plates, and the edge wheels can vertically move along the limiting plates and be locked. A center wheel is arranged on the lower side of the rear portion of the center frame, the vertical position of the center wheel can be adjusted, the center wheel can be locked, the center wheel is located behind the two side wheels, and the center wheel and the two side wheels serve as walking wheels of the whole mechanism. The mechanism can stably and accurately carry out chiseling operation on the batten wall, the chiseling position and depth can be accurately controlled, and the construction quality is good.

A holder for a rotary drill bit and / or pickaxe, comprising a tapered body section and a slot extending from a forward end to a distal end of the holder. The slot includes a slot profile formed by the configuration or design of a first radial end surface of the slot and a second radial end surface of the slot. The holder includes a distal portion with a reduced diameter adjacent to the distal end of the holder, wherein the distal portion with reduced diameter comprises a forward portion and a distal section, each having an outer diameter less than the outer diameter of a side wall of the holder adjacent to the distal portion with reduced diameter.The forward portion of the distal section with reduced diameter is tapered axially inwards in the distal direction, and the distal portion of the distal part with reduced diameter can be cylindrical or tapered axially inwards in the distal direction, as described in the exemplary illustrated embodiments.