Shear blade and cutting device

Abstract

A shear blade is for a portable hydraulic cutting device having a blade body. The blade body has assembly and cutting regions, with a cutting edge in the cutting region. A contact surface is on one side of the cutting edge for an additional shear blade. An outer surface on the other side of the cutting edge acts on the object to be cut. A first surface portion of the outer surface extends away from the cutting edge along an orthogonal, which meets the contact surface at the cutting edge, or at an acute angle relative to the orthogonal. A second surface portion connects to the first surface portion at an acute angle to the orthogonal. A third surface portion connects to the second surface portion at an acute angle to the orthogonal. Angle is smaller than angle , which is smaller than angle .

Claims

1. A shear blade for a portable cutting device comprising: a blade body, wherein the blade body has an assembly region and a cutting region; a cutting edge in the cutting region; a contact surface located on one side of the cutting edge for an additional shear blade and an outer surface located on the other side of the cutting edge, acting on an object to be cut; a first surface portion of the outer surface extends away from the cutting edge along an orthogonal line, which meets the contact surface at the cutting edge, or at an acute first angle relative to the orthogonal line; a second surface portion connects to an end of the first surface portion and is oriented in an acute second angle relative to the orthogonal line; a third surface portion connects to an end of the second surface portion and is oriented in an acute third angle relative to the orthogonal line; wherein the first angle is smaller than the second angle, and the second angle is smaller than the third angle; wherein a surface profiling is provided only in a region of the second surface portion and/or the third surface portion of the outer surface.

2. The shear blade according to claim 1, wherein, in a cross-section of the shear blade, a width of the first surface portion is smaller than a width of the second surface portion, and the width of the second surface portion is smaller than a width of the third surface portion.

3. The shear blade according to claim 1, wherein the first angle lies in a range from 0.5 to 5.

4. The shear blade according to claim 1, wherein the third angle is greater than/equal to 45.

5. The shear blade according to claim 1, wherein the surface profiling extends over an entire width of the respective surface portion.

6. The shear blade according to claim 1, wherein the surface profiling comprises individual parallel grooves.

7. The shear blade according to claim 6, wherein the grooves each comprise two opposite groove walls, one of the groove walls runs in a steep manner, and the other of the groove walls runs in a flattened manner, wherein the steeply running one of the groove walls is arranged on a side of the groove facing a blade tip of the shear blade.

8. The shear blade according to claim 6, wherein the grooves are U-shaped, V-shaped, or trapeze-shaped.

9. The shear blade according to claim 1, wherein the cutting edge is curved in a concave manner.

10. The shear blade according to claim 1, wherein the assembly region has a through opening for receiving a rotation axis element, which a pair of the shear blades have in common, and a through opening for connecting an actuation element on a side of a drive.

11. The shear blade according to claim 1, wherein the cutting region has a recess for receiving a cutting insert.

12. The shear blade according to claim 11, wherein the recess is configured such that the cutting insert is insertable in the recess at an acute angle to the contact surface of the shear blade.

13. The shear blade according to claim 11, wherein at least one fastening element is provided, an orientation of the at least one fastening element runs at a slanted angle to the contact surface.

14. The shear blade according to claim 11, comprising an undercut on at least one side of the recess.

15. A portable cutting device comprising: a housing, a hydraulic cylinder, a manually operable, hydraulic control valve, two tool halves connected to a rotation axis, each of the tool halves comprising a shear blade according to claim 1.

Description

DESCRIPTION OF THE INVENTION USING EMBODIMENTS

(1) Expedient embodiments of the present invention are described in more detail using the drawings.

(2) FIG. 1 shows a greatly simplified perspective view of a shear blade according to the invention;

(3) FIG. 2 shows a simplified perspective view of a shear blade according to the invention;

(4) FIG. 3 shows a simplified, merely schematic cross-sectional view of a shear blade according to the invention;

(5) FIG. 4a shows a simplified perspective cross-sectional view of a part of a design of the surface profiling according to the invention;

(6) FIG. 4b shows a second simplified perspective cross-sectional view of a part of a second design of the surface profiling according to the invention;

(7) FIG. 5 shows a simplified perspective view of a shear blade according to the invention with a cutting insert;

(8) FIG. 6a shows a simplified perspective partial view of the shear blade according to the invention from FIG. 5 with missing cutting insert;

(9) FIG. 6b shows a second simplified perspective partial view of the shear blade according to the invention from FIG. 5 with inserted cutting insert; and

(10) FIG. 7 shows a simplified, merely schematic cross-sectional view of the shear blade according to the invention from FIG. 5.

(11) Reference sign 1 in FIG. 1 denotes the portable cutting device for cutting and severing body parts and vehicle doors. The cutting device 1 has a housing 3 and a hydraulic cylinder 4, to which two tool halves are fastened that each comprise a shear blade 2 with a blade body 9 and a blade tip 9a located on said blade body 9. The shear blades 2 are arranged on a common rotation axis 6, and so the shear blades 2 can be pivoted against one another. In the region of the housing 3 and/or the hydraulic cylinder 4, a carrying handle 7 and a handle 8 for carrying the cutting device 1 are additionally arranged. Furthermore, a manually operable control valve 5, which allows the user to manually operate the cutting device (cutting, opening, and idling) is located in the region of the handle 8.

(12) FIG. 2 shows the shear blade 2 of the cutting device 1 in detail. The blade body 9 can preferably be manufactured as a forging or milled from a semi-finished product or a material plate. The blade body 9 comprises recesses 10 which function as a weight reduction of the shear blade 2. The shear blade 2 further comprises an assembly region 18, by means of which the shear blade 2 can be mounted on the cutting device 1. The assembly region 18 comprises a through opening 11 which is used to receive a rotation axis element, e.g., a central bolt (not depicted in FIG. 2), in order to fasten the shear blade 2 to the common rotation axis 6. The assembly region 18 further comprises a through opening 12 which can receive an actuation element, e.g., a safety bolt (not depicted in FIG. 2), on the side of the drive, by means of which the shear blade can be mounted on a lever member of a tool arm in order to control the shear blade 2.

(13) The shear blade 2 comprises a preferably concave cutting region 15 which is used to cut and sever the object to be cut. The object to be cut is cut by a cutting edge 16 and pushed apart along an outer surface 14 of the blade body 9. According to the invention, the outer surface 14 comprises a first surface portion 17a which extends away from the cutting edge 16. A second surface portion 17b connects to the end of the first surface portion 17a, and a third surface portion 17c connects to the second surface portion 17b.

(14) FIG. 3 shows a cross-section of a shear blade 2 according to the invention in the middle cutting region 15. Reference sign 13 denotes a contact surface lying opposite of the outer surface 14. During the opening and closing of the pair of shear blades of a cutting device 1, the shear blades 2 are guided past one another along their contact surfaces 13. The first surface portion 17a extends away from the cutting edge 16 at a small angle relative to the orthogonal O. The orthogonal O runs perpendicularly to the contact surface 13 and meets said contact surface 13 in the region of the cutting edge 16. The angle is preferably 0.5, 1.0, 1.5, 2.0, or 2.5. The second surface portion 17b, which connects to the first surface portion 17a, extends at an acute angle relative to the orthogonal O. The angle lies preferably in a range from 15 to 35, preferably from 20 to 25. A third surface portion 17c connects to the second surface portion 17b and is oriented in an acute angle relative to the orthogonal O. The angle is preferably 40, 45, or 50. Accordingly, the angle is smaller than the angle , and the angle is smaller than the angle . The angle is maximally 80, preferably 70, particularly preferably 60.

(15) The width of the first surface portion 17a lies preferably in the range from 0.5 to 1.5 mm; the width of the first surface portion 17a lies particularly preferably in the range from 0.5 mm to 0.7 mm. As seen from the cross-section of the shear blade 2, the width of the first surface portion 17a is smaller than the width of the second surface portion 17b, and the width of the second surface portion 17b is smaller than the width of the third surface portion 17c.

(16) In the cutting region 15, the shear blade 2 in FIG. 2 has a surface profiling 19. The surface profiling 19, for example, can consist of parallel grooves 20 as shown in FIG. 4a. The grooves 20 each comprise two opposite groove walls 20a, 20b and are designed to be trapeze-shaped, wherein the corresponding trapezes form plateaus 20c on the upper side which delimit the surface profiling 19 outwardly toward the object to be cut. With the introduction of said grooves 20, the cutting force onto the material to be cut is converted into a higher cutting pressure. As a result, the material to be cut is subject to a greater stress, resulting in an earlier breakdown. The design of the outer surface 14 with said grooves 20 generally results in a pressure conservation of 3-8%. Therefore, this provides the possibility of increasing the cutting power at a constant force and a constant weight.

(17) Expediently, the surface profiling 19 is located only in the region of the second and/or third surface portion 17b, 17c, preferably running over the entire width of the respective surface portion 17b and/or 17c. This design is advantageous because at the beginning of the cutting process, the object to be cut is pulled along the cutting edge 16 in the direction toward the rotation axis 6, and so the main cutting pressure is applied to the object to be cut by the rear part of the cutting region 15. In the region of the first surface portion 17a, no surface profiling 19 is provided. The pulling in of the object to be cut in the direction of the cutting device 1 is further facilitated by the cutting edge 16 being curved in a concave manner.

(18) In order to further improve the effect of the pulling in of the object to be cut, i.e., to allow for the pulling in also during the initial cutting process, a specific design of the surface profiling 19 or the grooves 20 according to FIG. 4a can be provided. For that purpose, the grooves 20 have a groove wall 20a which runs in a steep and curved manner, and a groove wall 20b which runs in a flattened manner. Such grooves 20, for example, can be milled with a V-shaped milling cutter which is placed obliquely onto the material. Depending on the distance selected for the milled grooves 20, plateaus 20c, which delimit the surface profiling 19 toward the side facing the object to be cut, are located between the grooves 20.

(19) FIG. 5 shows a second embodiment of the shear blade 2 according to the invention. Here, the shear blade 2 has a cutting insert 21 in the middle and rear part of the cutting region 15. For reasons of clarity, no surface profiling 19 is shown in FIG. 5 which, however, can also be present in the embodiment according to FIG. 5. The cutting insert 21 is fastened to the blade body 9 of the shear blade 2 by means of fastening elements 23. For example, screws, bolts, or the like can be used as the fastening element 23. The cutting insert 21 is inserted in the region of the cutting region 15 which is subject to greater stresses during cutting and thus subject to earlier wear. As a result, the cutting insert 21 can be replaced in case of wear in this region, and the function of the shear blade 2 can be restored without having to replace the entire shear blade 2. In addition, the cutting insert 21 can be made of harder or more resilient material than the basic material of the shear blade 2 in order to reduce the risk of wear and to improve the cutting force. As a result, the cutting power and the durability of the entire shear blade 2 can be improved at almost constant costs and weight. The cutting insert 21 can furthermore also comprise surface portions 17a, 17b, 17c (not depicted in FIG. 5).

(20) Expediently, in the region of the cutting region 15, the shear blade 2 has a recess 22 which is shown in FIG. 6a and is used to receive the cutting insert 21. The recess 22 has undercuts 24a at the front which are provided to hold the cutting insert 21 in position and/or to guide it during insertion. The cutting insert 21 and the recess 22, as shown in FIG. 6b, are manufactured such that a form closure is formed between the cutting insert 21 and the recess 22 as soon as the cutting insert 21 is completely introduced or inserted in the recess 22. For that purpose, the form closure is used to apply the overwhelming portion of the shear stresses occurring during cutting to the components of the shear blade 2 by means of compressive stresses.

(21) As shown in FIG. 7, the cutting insert 21 is inserted at a preferably acute angle to the contact surface 13. The insertion direction ER of the cutting insert 21 is marked in FIG. 7 with a black arrow. Here, the cutting insert 21 forms a part of the outer surface 14 and comprises, as does the outer surface 14, the surface regions 17a, 17b, 17c. After the insertion of the cutting insert 21, the cutting insert 21 is fastened to the blade body 9 by means of fastening elements 23. The orientation of the fastening elements 23 runs at an acute angle toward the contact surface 13 or essentially perpendicularly to the insertion direction ER. The attachments are geometrically designed such that they hold the cutting insert 21 in position within the recess 22 but are subject to as little stress as possible, such as notch stress peaks or high shear stresses, by applying the greater portion of the stresses, e.g., in the form of compressive stress, to the blade body 9 by means of the form closure between the cutting insert 21 and the recess 22.

(22) The disclosure expressly comprises individual combinations of features (sub-combinations) and possible combinations of individual features of different embodiments not shown in the drawings.

LIST OF REFERENCE SIGNS

(23) 1 Cutting device

(24) 2 Shear blade

(25) 3 Housing

(26) 4 Hydraulic cylinder

(27) 5 Control valve

(28) 6 Rotation axis

(29) 7 Carrying handle

(30) 8 Handle

(31) 9 Blade body

(32) 9a Blade tip

(33) 10 Recess

(34) 11 Through opening

(35) 12 Through opening

(36) 13 Contact surface

(37) 14 Outer surface

(38) 15 Cutting region

(39) 16 Cutting edge

(40) 17a first surface portion

(41) 17b second surface portion

(42) 17c third surface portion

(43) 18 Assembly region

(44) 19 Surface profiling

(45) 20 Groove

(46) 20a Groove wall

(47) 20b Groove wall

(48) 20c Plateau

(49) 21 Cutting insert

(50) 22 Recess

(51) 23 Fastening element

(52) 24a Undercut

(53) 24b Undercut

(54) O Orthogonal

(55) ER Insertion direction

(56) Angle

(57) Angle

(58) Angle

(59) Angle

(60) Angle