WO2021004602A1

WO2021004602A1 - Retainer assembly for securing an inner crushing shell

Info

Publication number: WO2021004602A1
Application number: PCT/EP2019/068078
Authority: WO
Inventors: Sukrija DAUTOVIC
Original assignee: Sandvik Srp Ab
Priority date: 2019-07-05
Filing date: 2019-07-05
Publication date: 2021-01-14

Abstract

A retainer assembly (10) for securing an inner crushing shell (2) on a shaft mounted head (3) of a gyratory crusher, the assembly (10) comprising: a head nut (11) having a first surface (111) to be radially inward facing towards a main shaft (1) of the crusher and a second surface (112) to be radially outward facing towards an axial upper region (21) of the shell (2), and at least one support ring (12, 13) arranged between the head nut (11) and the main shaft (1). Further a gyratory crusher comprising a retainer assembly is disclosed.

Description

Retainer assembly for securing an inner crushing shell

Field of invention

The present invention relates to a retainer assembly for securing an inner crushing shell on a main shaft mounted crushing head of a gyratory crusher.

Background

Gyratory crushers are used for crushing stone, ore, mineral and rock material to smaller sizes. Typically, the crusher comprises a crushing head mounted upon an elongate main shaft. A first crushing shell (typically referred to as a mantle) is mounted on the crushing head and a second crushing shell (typically referred to as a concave) is mounted on a frame such that the first and second crushing shells define together a crushing chamber through which the material to be crushed is passed. A driving device positioned at a lower region of the main shaft is configured to rotate an eccentric assembly positioned about the shaft, so as to cause the crushing head to perform a gyratory pendulum movement and crush the material introduced in the crushing chamber.

With use, the inner and outer crushing shells become worn and require replacement at regular intervals. It is therefore important to provide a retaining mechanism for convenient releasable mounting of the shells at the crusher frame and the crushing head. A variety of different assemblies have been proposed for mounting the inner crushing shell at the main shaft in an attempt to both provide a reliable lock and convenient mounting and dismounting of the mantle. Conventional arrangements are still disadvantageous as it is typically required to use welding for assembling and to use a cutting blowpipe or sledge hammer for removal. The assemblies of conventional arrangements for mounting the inner crushing shell at the main shaft cannot always appropriate handle the significant crushing forces and torques induced during crushing. During normal use crushing forces are transmitted around the shaft with a frequence of approximately 5 times per second. EP 2 929 940 discloses an examplary mantle retainer assembly comprising a head nut for securing an inner crushing shell on a crushing head at a main shaft that allows both attachment and detachment of the mantle. However, this retainer assembly might still require great forces by the use of gas cutting or the use of a sledge hammer in order to dismantle components arranged in connection to the main shaft. The reason for needing to use extraordinary forces is normally due to threads getting jammed since they have been biased or arranged with the wrong angle, so the threads become worn out faster than during normal use. The threads might be wrongly inclined already when assembling the crusher.

If threads are to be engaged, even if there is a mismatch between the threading

components, the mismatch will increase while the crusher is working and the dismantling will become even more cumbersome.

There is a need to not have to destroy the threads and to use great forces when dismantling the crusher. This leads to extra costs since components get broken that could have had a longer life time. It is also a safety risk when extraordinary forces are required during dismantling.

Thus, what is required is a retainer assembly that addresses the above problems.

Summary

It is an object of the present invention to provide a retainer assembly with adequate support of the threaded coupling of the main shaft, i.e. between the head nut and the main shaft. Further there is an object to have support during mounting of the crusher in order for the threads to become arranged as intended when assembling, i.e. for the head nut to be mainly perpendicularly arranged in comparison to the main shaft, in order for the threaded parts to not be wrongly inclined from the beginning. Another object is to have adequate support for the main shaft and the crusher throughout the use of the crusher, so that dismantling can be made in a safe way and without need to use excessive force.

The objectives are achieved by providing a retainer assembly with appropriate support of the main shaft, such that the threaded components are correctly arranged in order to functioning as long as expected and that these components not become a safety risk when the crusher is taken apart e.g. for maintainance.

According to a first aspect of the present invention there is provided a retainer assembly for securing an inner crushing shell on a shaft mounted head of a gyratory crusher, the assembly comprising a head nut having a first surface to be radially inward facing towards a main shaft of the crusher and a second surface to be radially outward facing towards an axial upper region of the shell, and at least one support ring arranged between the head nut and the main shaft. This gives less wear on the shaft and the threads.

Preferably the assembly comprises two support rings arranged as an upper support ring and a lower support ring. This is important in order to have a good balanced support of the retainer assembly.

Optionally the upper support ring is arranged flush with the upper end of the head nut and the lower support ring is arranged flush with the lower end of the head nut. This is valuable since it requires no extra space, while at the same time it gives optimal support.

Optionally the support rings are arranged radially between the head nut and an inner threaded ring that supports the main shaft. This gives a tight contact and good support of the mantle on the shaft, which gives optimal crushing conditions.

Preferably the support rings are made of a softer material than the head nut and the inner threaded ring. A softer and more flexible material is best suited to take up the forces transmitted during crushing through the head nut from the mantle.

Preferably the height of each support ring is 10 to 15% of the height of the head nut.

This specific height gives optimal support and balance.

Preferably the height of the upper support ring and the height of the lower support ring is the same. This is advantageous in order to simplify the assembly of the crusher. Optionally the height of the lower support ring is 80 to 100% of the height of the upper support ring. This is advantageous as it provides most support where most of the force is transmitted, since during normal use of the crusher higher forces are applied on the upper part of the head nut.

Optionally the height of the upper support ring is 80 to 100% of the height of the lower support ring. This enables adaptation to an alternative design.

Optionally the assembly comprises a torch ring arranged between the axial upper region of the shell and the head nut. The torch ring gives good support and helps to distribute and absorb forces from the shell before reaching the head nut, so that the head nut and the connecting threads experience lower and more evenly distributed forces.

According to a second aspect of the present invention there is provided a gyratory crusher comprising an elongate main shaft for gyroscopic precession within the crusher;

a head mounted at the main shaft an inner crushing shell mounted at the head; and a retainer assembly as claimed herein configured to releasably mount the shell on the head.

A specific implementation of the present invention will now be described by way of example only and with reference to the following drawings in which:

Figure 1 is a cross-sectional side view of a gyratory crusher having a retainer assembly for securing an inner crushing shell on a shaft mounted head of a gyratory crusher;

Figure 2 is a magnified view of the cross-sectional side view of figure 1;

Figure 3 is a cross-sectional side view of a further embodiment of a retainer assembly for securing an inner crushing shell on a shaft mounted head of a gyratory crusher;

Figure 4 is a magnified view of the cross-sectional side view of figure 3. Detailed description

Figure 1 discloses a retainer assembly 10 of a gyratory crusher. The retainer assembly 10 aims to secure an inner crushing shell 2 on a conical shaped head 3 that is arranged on a vertical shaft 1. The shaft is rotatably driven by suitable drives and gears (not shown) to precess within the crusher to displace the inner crushing shell 2 radially relative to an outer crushing shell (not shown). The inner crushing shell 2, also referred to as a mantle, is releasably retained at the head 3 via the retainer assembly 10, which is generally concentric relative to the mantle 2 and the shaft 1 so as to be centred on a longitudinal axis extending through the shaft 1. A head nut 11 being part of the retainer assembly is also disclosed. The retainer assembly should be convenient both for attachment and detachment of the crusher, and also be able to resist loading forces transmitted through the crusher and the retainer assembly during use.

Figure 3 discloses a further embodiment of a retainer assembly 10 of a gyratory crusher.

As in figure 1 the retainer assembly 10 aims to secure an inner crushing shell 2 on a conical shaped head 3 that is arranged on a vertical shaft 1. The description of figure 1 is also applicable on figure 3.

The retainer assembly 10 is a modular construction being further described in relation to figures 2 and 4. The retainer assembly 10 comprises a head nut 11 and at least one support ring 12, 13. The head nut 11 is centred around the longitudinal axis extending through the shaft 1 and having a first surface 111 towards the shaft, so facing radially inward and being mainly parallel with the outside of the shaft. The head nut has a second surface 112 facing radially outward towards the shell and more specifically an axial upper part 21 of the shell. The second surface 112 is generally parallel with the first surface 111.

Radially inwardly of the head nut an upper support ring 12 and a lower support ring are arranged. They are preferably arranged at the most upper end and at the most lower end, respectively seen in the axial direction of the head nut 11. The axial height of the upper support ring is defined as Hu and the axial height of the lower support ring is defined as HI. Both heights Hu and HI could be the same as seen in figure 2. The height of the support rings Hu and HI is normally 10 to 15% of the head nut height Hh, but could also be 15 to 20% or slightly smaller than 10%, such as 7 to 9%.

One of the support rings could also be larger than the other. The specific size of the support rings depends on requirements in regards of force distribution and what possibility exists considering space constraints. The upper support ring 12 could have a height of 80%, 90% or slightly smaller than the lower support ring 13. Or the lower support ring 13 could be smaller than the upper support ring 12 such that the lower support ring 13 could have a height of 80%, 90% or slightly smaller than the upper support ring 12.

Figures 2 and 4 further disclose an inner ring 14 arranged radially between the shaft 1 and the head nut 11. The inner ring 14 is arranged in threaded connection with the shaft 1 and with the head nut 11. The axial height of the threaded inner ring 14 is approximately the same as the head nut height Hh. The threaded inner ring 14 has a threaded engagement with the head nut 11 at approximately 50 to 75% of the axial height of the threaded inner ring 14. The threaded inner ring 14 has approximately the same axial height as the head nut 11. In connection to the location of the support rings 12 and 13 there may be a void between the threaded inner ring 14 and the head nut, these voids are preferably located in the axial direction just below the upper support ring 12 and above the lower support ring 13.

The axial height of the head nut is defined as Hh. The axial extension of the second surface 112 corresponds to approximately half of the head nut height Hh. The second surface 112 is arranged at the lower axial part of the head nut height Hh. The axial extension of the second surface 112 may be 40%, 50% or 60% of the head nut height Hh. The axial upper part of the head nut 11 facing radially outward comprises a chamfered surface 113. The chamfered surface 113 has an extension being mainly parallel with an upper outside chamfered surface of the shell 2.

In the first embodiment shown in figures 1 and 2 the chamfered surface 113 of the head nut is arranged to be adjacent and in contact with the axial upper part 21 of the shell. In the second embodiment represented in figures 3 and 4 the chamfered surface 113 of the head nut is arranged with a distance to the axial upper part 21 of the shell. The distance is filled with a torch ring 15 being arranged in contact with the chamfered side surface 113 of the head nut and on the diametrical opposite side in contact with the axial upper part 21 of the shell.

The support rings 12 and 13 are made of a softer and more flexible material than the head nut 11 and the inner threaded ring 14. Normally, the head nut 11 is made of casted steel and the inner threaded ring 14 is made of steel. The support rings are preferably manufactured in plastic or bronze. The material needs to have some flexibility, while also being rigid enough to take forces. Moreover, the material needs to be durable and not prone to cracking.

Claims

1. A retainer assembly (10) for securing an inner crushing shell (2) on a shaft mounted head (3) of a gyratory crusher, the assembly (10) comprising:

a head nut (11) having a first surface (111) to be radially inward facing towards a main shaft (1) of the crusher and a second surface (112) to be radially outward facing towards an axial upper region (21) of the shell (2), and

at least one support ring (12, 13) arranged between the head nut (11) and the main shaft (1).

2. The retainer assembly (10) as claimed in claim 1 wherein the assembly comprises two support rings arranged as an upper support ring (12) and a lower support ring (13).

3. The retainer assembly (10) as claimed in claim 2 wherein the upper support ring

(12) is arranged flush with the upper end of the head nut (11) and the lower support ring

(13) is arranged flush with the lower end of the head nut (11).

4. The retainer assembly (10) as claimed in any preceding claim wherein the support rings (12, 13) are arranged radially between the head nut (11) and an inner threaded ring

(14) that supports the main shaft (1).

5. The retainer assembly (10) as claimed in any preceding claim wherein the support rings (12, 13) are made of a softer material than the head nut (11) and the inner threaded ring (14).

6. The retainer assembly (10) as claimed in any preceding claim wherein the height of each support ring (Hu, HI) is 10 to 15% of the height of the head nut (Hh).

7. The retainer assembly (10) as claimed in any of claims 2 to 6 wherein the height of the upper support ring (Hu) and the height of the lower support ring (Hi) is the same. 8. The retainer assembly (10) as claimed in any of claims 2 to 6 wherein the height of the lower support ring (HI) is 80 to 100% of the height of the upper support ring (Hu).

9. The retainer assembly (10) as claimed in any of claims 2 to 6 wherein the height of the upper support ring (Hu) is 80 to 100% of the height of the lower support ring (HI).

10. The retainer assembly (10) as claimed in any preceding claim wherein the assembly comprises a torch ring (15) arranged between the axial upper region (21) of the shell (2) and the head nut (11).

11. A gyratory crusher comprising an elongate main shaft (1) for gyroscopic precession within the crusher;

a head (3) mounted at the main shaft (1);

an inner crushing shell (2) mounted at the head (3); and

a retainer assembly (10) as claimed in any preceding claim configured to releasably mount the shell (2) on the head (3).