DE10335858A1 - Chisel with a head and a shaft comprises a hard-metal insert which is glued into the cutout in the chisel head - Google Patents

Abstract

The chisel (1) with a head (4) and a shaft (3) comprises a hard-metal insert (2) which is glued into the cutout (7) in the chisel head. An independent claim is also included for a method for producing the proposed chisel.

Description

Become a chisel for different ones Used, inter alia, in impact or milling tools, e.g. in mining or demolition of foundations or paving to break or crush them. The chisels are subject to one unavoidable material wear. For these uses is it is advantageous if in the front region of the hardened chisel a carbide insert with a higher one Hardness arranged is. The chisel head is provided with a recess into which the carbide insert used and usually soldered becomes. Usually occurs melting the solder and hardening of the chisel main body at the same time in a multi-step process.

at In this process, a plurality are more similar in hardness chisel produced. The disadvantage, however, is that it requires relatively complex special machines and stoves necessary. Furthermore can produced in a procedure only almost equally hard chisel body become.

So far can Chisel basic body only in a hardness range in larger quantities be produced economically. A production of basic bodies with different hardnesses, would be per manufacturing batch lower quantities and necessitate other methods, e.g. the use of different Solder at different process temperatures, what the cost in the Height drives.

Task and Advantages of the invention

task The present invention is to a generic chisel with at least approximately comparable lifetime available with respect to conventional bits provide, in an economically advantageous manner, even in small quantities produced and comparatively easy to different Purpose is interpretable.

These The object is based on the features of the preamble of the independent claims 1 and 9 by the characterizing features of claim 1 and of Procedure claim 9 solved. By the mentioned in the dependent claims Features are functional and advantageous developments of the invention possible.

So becomes a chisel with a holding section, e.g. Chisel shaft, and a chisel head, having a recess in which a cemented carbide insert attached is proposed, which is characterized in that the carbide insert is glued in the recess.

By the gluing of the cemented carbide insert becomes a high-strength connection obtained from carbide insert and chisel base, without that elaborate Plants or

special machines and complicated procedures for it necessary. The gluing of the cemented carbide insert can advantageously even at room temperature. Mostly the drying and Harden of the adhesive, however, with a comparatively moderate increase in temperature, e.g. at 100 ° C to 180 ° C instead. The strength of the adhesive bond can be readily the strength a solder joint to reach. In part, the strength of an adhesive bond can even that exceed a solder joint.

One Another essential aspect of the invention is that different types of chisels, in hardness of the chisel base body, in an economically advantageous manner by gluing the cemented carbide insert can be produced.

The Chisels according to the invention can be simple and cost-effective be adapted almost optimally to the respective requirement. Thereby will increase the life of the chisel compared to conventional chisel clearly increased.

With the chisel according to the invention can over conventional chisel e.g. the wear behavior of the chisel head when processing e.g. be significantly improved by sandstone. In addition, can be prevented when working on concrete the chisel head from the chisel regularly breaks off, like it at usual chisel can be observed in practice.

One inventive chisel basic body with cemented carbide insert may have Rockwell hardnesses of HRC 50 to 60, e.g. for the Work on sandstone, or from HRC 40 to 50 for normal milling work or hardening from HRC 35 to 40 for have the processing of concrete with reinforcement, without the Making it more complicated and expensive.

Another essential aspect of the invention relates to the fact that securing means are provided for securing the cemented carbide insert in the recess. A fuse of carbide insert can improve its exact fixation in the recess and increase the useful life of the bit. For example, a round wire snap ring in each case a groove of the hard metal Latch insert and the recess with it exactly positioned carbide insert. A round wire snap ring can, to some extent, absorb mechanical stresses in the bit bit and improve the stability of the bit. In addition, an early fall out of the cemented carbide insert can be counteracted from the recess. Such an embodiment is not only advantageous in connection with the gluing of the cemented carbide insert, but can also preferably be used alone or in combination with other compound variants. In addition to a round cross section, other cross sections of the wire snap ring come into question, for example, square or rectangular.

A expedient embodiment of the subject invention provides that the carbide insert a substantially cylindrical insertion portion, with the the cemented carbide insert is glued in a hole. The advantage this solution in the manner of a plug-in mechanism lies in particular in the simple Production and the achievable very good positive connection Of the parts.

It is of particular advantage when gluing the cemented carbide insert Adhesive are provided, which are constructed on epoxy resin-based. Such adhesives are especially useful for bonding metals or metal alloys suitable. Furthermore They are characterized by high impact resistance and heat resistance out. These adhesives, e.g. Bylapox OP-32, can have the same or even higher tensile shear strengths like solder joints exhibit.

According to the invention will continue suggested that means for enlarging the surface at least of the insertion section are provided. An enlarged surface of the Insertion section of the Carbide insert improves in particular the solder or adhesive bond between insertion section and recess, as a larger adhesion-promoting surface to disposal stands. Additionally or Alternatively, an enlargement of the surface the recess advantageous. For an enlargement of surfaces can this e.g. roughened, e.g. by galvanic pickling, during or after the production of the components.

According to one particular embodiment of the Subject of the invention are means for substantially uniform training the adhesive connection provided in the recess. A uniformly trained Adhesive bonding is particularly durable and strong because e.g. defects of adhesives and different adhesive layer thicknesses are avoided. to even education of the Soldering or Adhesive bonding is e.g. a defined constant gap thickness realized between carbide insert and recess.

is for example, the insertion section cylindrical and the recess as a matching round hole with trained little game leaves the adhesive bond through a defined circular gap largely train equally.

According to one particular embodiment of the Subject of the invention, the chisel head characterized by the fact that he in the area around the opening the recess with a circumferential elevation and / or depression is provided, whereby a groove-like receiving volume on the chisel head can be trained. The recording volume can be in different ways will be realized.

at inserted cemented carbide insert may e.g. between one or also several circumferential survey (s) and the carbide insert form a recording volume. For several surveys, the recording volume also be divided into several sub-volumes, e.g. in the way of one Double trough. Furthermore Is it possible a radially outward to form a wide recess, in the upper region to the opening of the Recess towards a receiving volume is formed when the carbide insert is inserted in the recess. Furthermore, it may be an advantage be a recess, for example, as a groove in the opening of the Recess in the chisel head ausformieren, whereby not used carbide insert or only in cooperation with the inserted cemented carbide insert the Recording volume is formed.

On different ways can thus excess adhesive, such. Lot or adhesive, not in the gap between carbide insert and the recess takes place, be collected. For later use of the chisel is after the shortest Time compared to the chisel head comparatively small dimension survey by wear disappeared and can not be annoying on the use of the chisel impact. Advantageously leaves the circumferential survey and / or depression without a significant additional Expense e.g. continuously to realize the recess, e.g. in the shaping of the chisel base by Turning or the like.

The survey and / or depression can be particularly easily formed differently, for example profiled more or less strongly. The trough-like receiving volume formed on the bit head is suitable for receiving solder or adhesive and preventing it from running down the bit head when the longitudinal axis of the bit is substantially vertical. The trough-like volume is important until the solder or glue have lost their fluidity.

A Further development of the subject invention provides that on Chisel body marker are formed, the conclusions on to allow the technical characteristics of the basic body. With the help of Markings that are selected according to the hardness of the chisel body, the respective Chisel basic body fast and clearly identified and according to the requirement profile selected become. The marking agents include e.g. when turning attached Grooves, numbers and / or letters or color markings on the circumference or the front of the chisel.

According to the invention is also a Method for producing a chisel with a holding section e.g. drill collar and a chisel head that a recess in which a carbide insert at least is mounted in the region of the recess, proposed, wherein the Carbide insert is glued. Through this procedure can be in particular the effects on the structure or hardness of the Chisel basic body, the in other manufacturing processes, in particular a strong temperature increase make necessary, avoid. Another significant advantage of Invention is that with comparatively low machine or plant expenditure the attachment of the carbide insert in the chisel takes place. Especially for is comparatively small quantities the proposed method advantageous, which also small and medium-sized companies produce advantageously corresponding chisel can.

Finally will suggested that to dry the adhesive of the chisel given drying conditions is suspended. Under drying conditions are especially the drying time and the drying temperature, to understand. For example, can the chisel with carbide insert for one hour under air atmosphere to approx. Be heated 120 ° C. Some adhesives also dry at room temperature, with longer drying times are necessary, e.g. multiple days.

drawing

One schematically illustrated embodiment The invention is illustrated in the drawing and in the following Description explaining further advantages and details explained in more detail.

The single figure shows a partially sectioned side view of a Round pick with glued carbide tip.

description of the embodiment

A round shank chisel 1 essentially has a main body and a carbide tip 2 on. The main body is subdivided into a holding section 3 and a chisel head 4 , The holding section 3 is essentially cylindrical 3 formed with a diameter d ₁ of about 30 mm. As a holding section but other shapes are possible, for example, a flange-like section. In the direction of the longitudinal axis A of the chisel 1 has the round shaft 3 a length l ₁ of about 75 mm and the chisel head with carbide tip 2 in about a length l ₂ of 70 mm. The outer contour of the chisel head 4 is shaped in the shape of a bell and tapers towards the front. The lower edge of the chisel head 4 is through a strip-shaped cylindrical area 5 formed with a diameter d ₂ of about 70 mm. The transition from the chisel head 4 to the round shaft 3 gets through a rounded throat 6 realized to counteract an adverse notch effect.

In the front area of the chisel head 4 is a round hole 7 Centric to the longitudinal axis A of the chisel 1 introduced, in which the carbide tip 2 close to a bottom of the hole 8th is inserted. It's also on a chisel 1 several identical or different carbide inserts 2 mountable. Here are the carbide inserts 2 also obliquely to the longitudinal axis A in the chisel head 4 be used. The carbide tip 2 is in its front portion with a cone-like or ballistic tip, for example 11 Mistake. It usually consists of known hard metal alloys, for example with proportions of titanium, tantalum and cobalt. The chisel tip 2 may also include other materials, such as diamond or ceramic materials. The cemented carbide insert is over a largely cylindrical Einklebabschnitt 9 in the round bore 7 glued. Thereby, the gap areas become 12 and 13 formed by a suitable adhesive 10 are filled.

Around the carbide tip 2 additionally in the round bore 7 To fix, a round wire snap ring connection is provided. In the process, the carbide tip becomes 2 and the round bore 7 with grooves 14 . 15 provided in which a round wire 16 is introduced.

For attachment of the round shank chisel 1 on a working device, such as an excavator, is on the round shaft 3 a cylindrical attachment portion 17 intended.

The chisel body 3 . 4 is usually one-storey made of hardenable steel. A possible method according to the invention for producing the round shank chisel 1 includes, for example, the following essential process steps: As Ausgangsmate The chisel blank material is drawn or rolled stock, which is first sawn to the appropriate length. Alternatively, a forged part could be used. The part thus obtained is then further processed in particular by machining, for example by turning. It is in the front of the chisel head 4 the round bore 7 brought in. In addition, it is advantageous if in the area around opening of the round bore 7 a circumferential collar 18 and / or a depression, for example a groove, is formed. Also, the diameter of the round bore could 8th be slightly widened in the upper part of the opening. For example, a ring-shaped circumferential collar 18 forms with inserted carbide tip 2 a kind of barrier or gutter 19 for excess glue 10 from the round hole 7 can run to the outside.

Subsequently, the chisel basic body 3 . 4 hardened and tempered to a desired Rockwell hardness of the chisel base depending on the application 3 . 4 to get. The HRC hardnesses are in hardness ranges of eg approx. 35 to 40, 40 to 50 or from 50 to 60. Depending on the hardness of the chisel base body 3 . 4 becomes the basic body 3 . 4 clearly marked. For housing a round wire snap ring 16 is in the bore wall of the hole 7 a groove 14 introduced perpendicular to the bore axis. The cylindrical gluing section 9 is also with a groove 15 equipped in the circumferential direction. For larger quantities, it may also be advantageous to the groove 15 already in the production of the carbide insert 2 train. In the groove 15 the carbide tip becomes a corresponding round wire snap ring 16 inserted and compressed with a pair of pliers to the snap ring 16 and the carbide tip 2 in the round bore 7 in the chisel head 4 to be able to introduce. The hard metal tip is preferred 2 with the round wire snap ring 16 pressed. before pressing is preferably the high-viscosity adhesive 10 into the hole 7 filled and / or at Einklebabschnitt 9 applied. When inserting the carbide tip 2 into the hole 7 the glue spreads 10 in the gap area 12 . 13 ,

For drying the glue 10 preset drying conditions are set.

1

Attack cutting tools

2

Carbide tip

3

drill collar

4

chisel head

5

cylindrical Area

6

around throat

7

round hole

8th

hole bottom

9

Einklebabschnitt

10

Glue

11

top

12

gap

13

gap

14

groove

15

groove

16

round wire

17

attachment section

18

collar

19

collecting channel

Claims (10)

Chisel ( 1 ) with a holding section ( 3 ), eg a bit shank, and a chisel head ( 4 ), which has a recess ( 7 ), in which a cemented carbide insert ( 2 ), characterized in that the cemented carbide insert ( 2 ) in the recess ( 7 ) is glued. Chisel according to the preamble of claim 1, in particular according to claim 1, characterized in that securing means ( 14 . 15 . 16 ) for securing the carbide insert ( 2 ) in the recess ( 7 ) are provided. Chisel according to Claim 1 or Claim 2, characterized in that the cemented carbide insert ( 2 ) has a substantially cylindrical insertion section ( 9 ), with which the hard metal insert ( 2 ) in a bore ( 7 ) is glued. Chisel according to one of the preceding claims, characterized in that for gluing the cemented carbide insert ( 2 ) Adhesives ( 10 ) are provided, which are constructed on epoxy resin-based. Chisel according to one of the preceding claims, characterized in that means for enlarging the surface of at least the insertion portion ( 9 ) are provided. Chisel according to one of the preceding claims, characterized in that means ( 12 . 13 ) for substantially uniform formation of an adhesive bond in the recess ( 7 ) are provided. Chisel according to one of the preceding claims, characterized in that the chisel head ( 4 ) in the area around the opening of the recess ( 7 ) with a rotating survey ( 18 ) and / or depression, with which a channel-like receiving volume ( 19 ) on the chisel head ( 4 ) can be formed. Chisel according to one of the preceding claims, characterized in that on a chisel base body ( 3 . 4 ) Marking means are formed, the conclusions on the technical egg characteristics of the basic body ( 3 . 4 ) allow. Method for producing a chisel, with a holding section ( 3 ), eg a bit shank, and a chisel head ( 4 ), which has a recess ( 7 ), in which a cemented carbide insert ( 2 ) at least in the region of the recess ( 7 ), characterized in that the cemented carbide insert ( 2 ) is glued. A method according to claim 9 or 10, characterized in that for drying the adhesive ( 10 ) the chisel ( 1 ) is exposed to predetermined drying conditions.