EP3289144A1

EP3289144A1 - Cutter head with a replaceable adapter

Info

Publication number: EP3289144A1
Application number: EP16733735.1A
Authority: EP
Inventors: Klaas Geert Wijma; Cornelis Martinus Petrus WEMPE; Paul BAHRAMIAN
Original assignee: Leo Dynamische Investering BV
Current assignee: Leo Dynamische Investering BV
Priority date: 2015-05-01
Filing date: 2016-04-28
Publication date: 2018-03-07
Also published as: WO2016178562A1; NL2014748B1; NL2014748A

Abstract

The invention relates to a cutter head (1) for an excavating device. The cutter head has at least one blade (10-10") with a recess (12-12") and an angled abutment surface (22). A tool has a holder shaft (15) fitting in the recess and a transverse head (16) connected via a bolt (24,25) clamping the contact surface (18,18') of the transverse head (16) against a liner (30) on the axial supporting surface (19,19') while leaving a play between the shaft (15) and the recess (12, 12").

Description

Cutter head with a replaceable adapter Field of the invention The invention relates to a cutter head for an excavating device comprising at least one blade with a recess, the blade comprising around the recess an a axial supporting surface, a tool holder and a tool, the tool holder engaging with the tool and having a holder shaft that is seated in the recess and a transverse head having a contact surface engaging with the axial supporting surface, the tool holder being removably attached to the blade via a connector member.

The invention also relates to a blade, a tool holder and a tool for use in such a cutter head. Background of the invention

Such a cutter head is known from WO2013/180615, in which a cutter head for a dredger is described having tool holders, or "adapters" carrying the teeth that can be easily released from the cutter head blades via a bolted connection of the lower end of the holder shaft. The bolted connection is accessible via an opening in the blades and needs to be disconnected and re-attached via a purpose-built tool.

The connection of the known adapters has as a disadvantage that fastening and unfastening of the adapters through the hole in the blades in difficult in view of the confined space and requires a dedicated hydraulic tool. Furthermore, the presence of a hole in the blades was found to weaken the strength of the blades.

Moreover, the bottom part of the known holder shaft was found to be subject to substantial wear due to the flexing of the adapters caused by high forces on the tools (teeth) when the cutter head is in operation. This flexing causes micro-movements between the different parts that in combination with water/sand mixtures result in accelerated wear. A cutter head according to the pre-amble of claim 1 is known from US patent application no. US 2005/0150666 showing a fixing device for a shank chisel in which a tool holder is clamped into a recess in a base element via a bracing element and a bolt. The tool holder can be replaced in an easy manner by releasing the bolt that can be accessed from an outwardly facing side of the device. However, the very stiff clamping connection of the tool holder may lead to damage when large forces, such as occur for instance during dredging in hard soil layers, are exerted on the chisel.

It is therefore an object of the present invention to provide a cutter head having an adapter carrying the tool, which adapter, or tool holder, can be easily exchanged while being able to withstand large forces.

It is furthermore an object of the invention to provide a cutter head having improved strength.

It is also an object of the invention to provide a cutter head and an adapter that are subject to reduced wear.

Summary of the invention

Hereto the cutter head according to the invention is characterized in that an axial liner is provided on the supporting surface near the recess, wherein the bolt clamps the contact surface of the transverse head against the liner on the axial supporting surface while a play is present between the shaft and a wall of the recess. Because the transverse head of the tool holder or "adapter" according to the invention is clamped against the axial supporting surface of the blade via the axial liner, and the shaft is for a large part "freely hanging" in the receiving cavity from the transverse head, the shaft can flex and bend within the receiving cavity. Hence the shaft, and therefore the whole adapter, can absorb very large forces. The transverse head is in this way firmly fixed and supported on the blade while being easily accessible for exchange, without requiring a hole in the blade. Hereby the strength of the blades is improved. In case of excessive wear, the axial liner is easily accessible for repair or replacement on the outer blade surface after removal of the adapter from the recess.

Furthermore, the clamping fastening at the top end of the adapter prevents micro movements of the shaft at the place of contact, which is at the liner locations, and hence reduces wear.

The axial liner that is provided between the axial supporting surface of the blade and the contact surface of the transverse head may be formed of a relatively wear resistant metal such as HARDOX^® and is replaced upon wear. A radial liner may also be provided inside the recess near the clamping device.

In an embodiment of a cutter head according to the invention, the axial liner is provided with an axial recess and the transverse head comprises an axially extending part that is received in the recess for preventing rotation of the shaft.

The tool holder can be easily aligned and given the proper angular orientation upon insertion into the recess in the blade by placing the axially extending part in the recess of the axial liner. In this manner rotation of the tool holder is prevented and wear is further reduced.

In a preferred embodiment of a cutter head according to the invention, the clamping device comprises a spring member pressing the contact surface of the transverse head against the axial supporting surface. In this manner a close and play-free contact between the adapter and the blade can be achieved.

The holder shaft may at a lower end be received with play in a bush that engages with its outer surface substantially without play with a lower part of the recess, no axial passage for access to the bush being provided in the blade. The reaction forces on the lower end of the holder shaft (the adapter) are now transferred to the blade through the bush-shaped liner. The shape of the bush is smooth and can be concave or convex and can have a circular, oval, rectangular triangular, or polygonal cross-section. The same applies to the cross-section of the holder shaft. In an embodiment of a cutter head according to the invention, the transverse head has a front lateral groove and a transverse groove, substantially transversely thereto that is near the clamping member provided with a tensioning device for releasably engaging with a middle part of the tool and pulling it in a rearward direction toward the clamping device such that a front transverse part of the tool engages with the front lateral groove. Via the tensioning device, the tools - such as teeth - can be easily connected and disconnected from the tool holder. Alternative tools may be used in combination with the inventive adapter, such as for instance teeth having a T-shaped cross-section but also other shaped cross-sections and comprising different materials depending on the material that is to be excavated.

Brief description of the drawings Some embodiments of a cutter head according to the invention will, by way of non- limiting example, be explained in detail with reference to the accompanying drawings. In the drawings:

Fig. 1 shows a perspective view of a cutter head comprising easily releasable tool holders according to the invention,

Fig. 2 shows a partly cut-away view of a blade carrying a tool holder according to the invention,

Fig. 3 shows a cross-sectional view through the tool holder of fig. 2 and

Fig. 4 shows an exploded view of the clamping device and liners according to the invention.

Detailed description of the invention

In fig. 1 a cutter head 1 is shown for an excavating device, in this case a dredger. The cutter head 1 comprises a base ring 2 and a central hub 3 between which a number of blades 10, 10', 10" extend in a spiral-shaped form. Each blade 10-10" has a spine 11 and an edge surface 8 having multiple recesses 12,12', 12" therein that extend into the blade in a direction perpendicular to the edge surface 8 and more or less parallel to the spine 11. Within each recess 12-12" a tool holder 13, 13', 13" is releasably received. The tool holders 13-13" each carry a tool, in this case a tooth 14,14', 14". The tools can have different shapes and hardness, depending on the environment and soil type with which they come into contact. The teeth 14-14" can be released from the tool holders 13-13" while the tool holders remain attached to the blades 10-10" via the recesses 12-12". The rate of wear of the teeth 14-14", and consequently the frequency of replacement, is higher than that of the tool holders 13-13" by for instance a factor 10. Each tool holder 13 has a holder shaft 15 and a transverse head 16. The transverse heads 16 are provided with a transverse groove 17 in which the tooth 14 is received. There is a predetermined distance, or play, between the holder shaft 15 and an inside wall of the recess 12-12", which may amount to 1 mm or more, for instance 5 mm. This is clearly seen in fig. 3. Hence the shaft 15 can flex within the recess 12-12".

As can be seen from fig. 2, the transverse head 16 has a contact surface 18, 18' that rests on an axial supporting surface 19, 19' of the blade 10, near the recess 12. A clamping device 20 is formed by a connector member 21 that is welded onto the blade 10. The connector member 21 has an angled abutment surface 22 against which a

complementary surface 23 on the transverse head 16 is supported. The orientation of the angled surfaces 22,23 is at an angle less than 90° relative the supporting surface 19', 19', for instance between 80° and 45°. Two spring-loaded bolts 24,25, each carrying a spring 26, 27, extend through aligned holes on the surfaces 22, 23 and clamp the transverse head 16 with its contact surfaces 18,18' against the axial supporting surfaces 19,19' of the blade 10, substantially without play, via an intermediate axial liner 30. By action of the clamping device 20, the holder shaft 15 is furthermore pressed into contact with radial liners 31, 31 ' that are provided inside the recess 12, and at a lower end 32 of the shaft 15, a bush 33 is pressed against the inside of the lower end of the recess 12. The recess 12 has a downwardly tapering shape.

As can be seen from fig. 3, the lower end 32 of the tool holder shaft 15 is received with play inside the bush 33, which may be smooth, concave or convex. The outside surface 34 of the bush 33 is pressed into contact with the inner surface of the recess 12. In order to prevent rotation of the tool holder 13, the transverse head 16 is provided with an axially extending part 35 that fits into a recess 36 in the axial liner 30, as can best be seen in fig. 4. The tooth 14 that is shown in this embodiment, is provided with a front lateral part 40 that fits into a front lateral groove 41 in the transverse head 16. A central part 46 of the tooth extends in the transverse groove 17 in the head 16 and is at a rear end 42, near the clamping device 20, provided with a hook member 43. A complementary hook member 44 attached to the transverse head 16 via bolt connection 45 releasably pulls the tooth 14 with its front lateral part 40 against the front lateral groove 41.

Claims

1. Cutter head (1) for an excavating device comprising at least one blade (10-10") with a recess (12-12"), the blade comprising around the recess an axial supporting surface (19, 19'), a tool holder (13-13") and a tool (14-14"), the tool holder engaging with the tool and having a holder shaft (15) that is seated in the recess (12-12") and a transverse head (16) having a contact surface (18,18') engaging with the axial supporting surface (19,19'), the tool holder (13-13") being removably attached to the blade (10-10") via a connector member (21) that is fixedly attached to the supporting surface (19,19') and that protrudes from the supporting surface (19,19'), the connector member (21) having an angled abutment surface (22) with at least one hole, the abutment surface (22) engaging with a complementary angled surface (23) on the transverse head (16) which complementary surface (23) is provided with at least one hole for receiving a bolt (24,25) through the hole and an aligned hole on the connector member (21), characterized in that, an axial liner (30) is provided on the supporting surface (19,19') near the recess (12-12"), wherein the bolt (24,25) clamps the contact surface (18, 18') of the transverse head (16) against the liner (30) on the axial supporting surface (19, 19') while a play is present between the shaft (15) and a wall of the recess (12,12").

2. Cutter head (1) according to claim 1, wherein the axial liner (30) is provided with an axial recess (36) and the transverse head (16) comprises an axially extending part (35) that is received in the recess (36) for preventing rotation of the shaft (15).

3. Cutter head (1) according to claim 1 or 2, wherein the clamping device (20) comprises a spring member (24,25,26,27) pressing the contact surface (18, 18') of the transverse head (16) against the axial supporting surface (19, 19').

4. Cutter head (1) according to claim 1,2 or 3, wherein the recess (12,12") has a tapering shape, the holder shaft (15) tapering from a broad part near the transverse head (16) to a narrow lower end (32), wherein the holder shaft (15) is at the lower end (32) received with play in a bush (33) that engages with an outer surface (34) substantially without play with a lower part of the recess (12-12"), no axial passage giving access to the bush being provided in the blade (10-10").

5. Cutter head (1) according to any of the preceding claims, wherein a radial liner (31-31 ") is provided in the recess (12-12") near the clamping device.

6. Cutter head (1) according to any of the preceding claims, wherein the transverse head (16) has a front lateral groove (41) and a transverse groove (17) substantially transversely thereto, and is near the clamping device (20) provided with a tensioning member ( 44,45) for releasably engaging with a middle part (43,46) of the tool (14) and pulling the tool in a rearward direction toward the clamping device (20) such that a front transverse part (40) of the tool engages with the front lateral groove (41).

7. Tool holder (13-13") for use in a cutter head (1) according to any of claims 1-6 comprising a holder shaft (15), a transverse head (16) having a contact surface (18,18') and a clamping surface (23) substantially transversely oriented to the contact surface (18,18'), with at least one hole for receiving a bolt, characterised in that, the holder shaft (15) extending transversely to the contact surface (18, 18') and tapering from a broad part near the transverse head (16) to a narrow lower end (32), the transverse head (16) being provided with a complementary angled abutment surface (23) having at least one through hole which for receiving a bolt (24,25) through the hole and an aligned hole on a connector member (21) on a blade (10,10') of the cutter head (1), an axially extending part (35) protruding from the contact surface (18, 18') for being received in a recess (36) on the blade (10,10') of the cutter head (10) for preventing rotation of the shaft (15).

8. Tool holder (13-13") according to claim 7, the shaft at a lower end (32) supporting a bush (33) with play.

9. Tool (14-14") for use in a cutter head (1) according to any of claims 1-6, comprising a central tool body (46) with a forward tool edge, a transverse tool part (40) extending transversely to the forward tool edge and a tensioning connector member (43) on the central tool body (46) at a side opposite the forward tool edge pulling the transverse tool part (40) into a lateral groove on a tool holder of the cutter head (1).