WO2014096542A1

WO2014096542A1 - Arrangement for rocker mechanism of crusher, especially jaw crusher

Info

Publication number: WO2014096542A1
Application number: PCT/FI2013/051178
Authority: WO
Inventors: Raimo VON HERTZEN
Original assignee: Aalto University Foundation
Priority date: 2012-12-21
Filing date: 2013-12-18
Publication date: 2014-06-26
Also published as: FI124260B; FI20126370A

Abstract

The invention relates to an arrangement for a rocker mechanism (2) of a crusher, especially a jaw crusher (1). The crusher (1) comprises a body (3), a first jaw part (4) arranged in an immobile manner on the body (3), a link mechanism (5) arranged in conjunction with the body (3), the mechanism comprising a second jaw part (6) forming a rocker, the second jaw part being arranged to move alongside the first jaw part (4), between two mobile joints (A, B) of the link mechanism (5), the first of the mobile joints (A) being formed into an eccentric shaft which is in periodic motion around the joint (O) which is immobile with respect to the body (3). In connection with which body (3) are provided balancing means (T⁺) arranged to rotate around the immobile joint (O) or a shaft parallel to it in one direction. The body (3) is provided with at least a second joint (P2) immovable with respect to the body (3), in connection with which are provided second balancing means (T^-) which are arranged to rotate around the second immobile joint (P2) in a direction opposite to the direction of rotation of the balancing means ( T⁺) in order to decrease or cancel out at least the horizontal inertial forces of mass (F_x) and vertical inertial forces of mass (F_y) of the first order of the periodic motion of the link mechanism (5), that is, the horizontal inertial forces of mass (F_x) and vertical inertial forces of mass (F_y) occurring at the operating frequency of the crusher. The angular speeds (ω) of the balancing means (T⁺) and of the second balancing means (T^-) are mutually equal.

Description

Arrangement for rocker mechanism of crusher, especially jaw crusher

The object of the present invention is an arrangement for a rocker mechanism of a crusher, especially a jaw crusher, the crusher comprising a body, a first jaw part arranged in an immobile manner on the body, a link mechanism arranged in conjunction with the body, the mechanism comprising a second jaw part forming a rocker, the second jaw part being arranged to move alongside the first jaw part, between two mobile joints of the link mechanism, the first of the mobile joints being made into an eccentric shaft which is in periodic motion around the joint which is immobile with respect to the body, and in conjunction with which body are provided balancing means arranged to rotate around the immobile joint or a shaft parallel with_:it. n,one,dicection, and- hich body is provided with at least a second joint immovable with respect to the body, in conjuntion with which are provided second balancing means arranged to rotate around a second immobile joint jn_; a direction opposite to the direction of rotation of the balancing means in order to decrease or cancel out at least the horizontal i nertial forces of mass generated, by the first order of the periodic, motion of the link mechanism, that is, at the operating frequency of the crusher. Previously are known jaw crushers of the above type, for.example, for crushing - rocks. One such jaw crusher is disclosed in the patent publication US 919,582A.^•It- describes a five-link mechanism, wherein the first order of. the horizontal inertial. force of mass is balanced by first balancing means. The purpose of the second bal^¬ ancing means is to balance the second order of the horizontal inertial force of mass by second balancing means rotating in the opposite direction at double the angular velocity. This arrangement does not, however, eliminate.or even decrease the vertical inertial forces of mass, nor the moment rocking the body.

Furthermore, from the published application US 2010206975 Al is known a typical crusher attached to the end of the bucket arm of an excavator, where in conjunction with the moving jaw is provided a counterweight for balance adjustment on an eccentric main shaft. By means of the counterweight is typically achieved partial balancing of horizontal and vertical inertial forces of mass. A typical and generally applied arrangement for the rocker mechanism of a jaw crusher is shown diagrammatically in Figure 1 describing the prior art. The rocker mechanism of a jaw crusher is, for example, a four-link mechanism which operates in such a way that the upper part of the rocker of the crusher performs a circular motion, as a result of which the rocker (second jaw part), and the crusher plate attached to it, performs an elliptic type movement and crushes the rocks 10 or other material against another stationary plate. The periodic motion of the massive rocker generates strong horizontal and vertical forces on the body of the jaw crusher and a strong moment rocking the body. These forces and the moment may be combined into the resultant F_x and F_y and M at point C. Point C is at the marked point only as an example. Point C is not bound to the point shown and may be se- leeted-freelyr hese loads-increase the level of oscillation -of he machine significant- ly, which increases malfunctions, fatigue breakage and noisiness of the machine and shortens the machine's service life. In connection with the immobile joint is arranged a flywheel or the like which is provided with balancing means rotating in one direction with the flywheel or the like. These balancing means are arranged in the rocker mechanism in such a way that they decrease either both the horizontal and vertical forces to some extent or eliminate essentially only one force component and do not, in practice, decisively effect the remaining force component reductively. This arrangement has no substantial reductive effect on the moment rocking the body.

From the publication US 4,749,136 A is previously known a further jaw crusher arrangement, wherein two jaw parts arranged opposite one another as a mirror image are arranged to move by their own means comprising eccentric masses. In this case, by means of the eccentric masses, which are mirror images of one another, are provided jaw parts moving in opposite directions at the same pace. The balancing of the arrangement is based on the mirror symmetry of the two jaw parts arranged to be mobile.

From the publication FR 2697175 Al is also known a crusher arrangement, where the movement of two jaw parts is effected by eccentric masses.

The problem with all of the foregoing arrangements is that, despite the balancing arrangements, none of the arrangements eliminates sufficiently both forces simultaneously, namely the horizontal inertial forces of mass and the vertical inertial forces of mass. Neither do any of the known crusher arrangements in the rocker mechanism eliminate or essentially decrease the moment rocking the body. Although the aim in current jaw crushers has been to decrease the above-mentioned forces and moment, it has not been possible to eliminate them essentially simultaneously. This means that due to the periodic operation of the link mechanism, on the body and link mechanism are exerted loads of the first order, which have an effect at the operating frequency of the machine, and loads of the second order, which have an effect at twice the operating frequency of the machine, etc. The aim of the present invention is to eliminate or substantially reduce the above- mentioned disadvantages, especially as concerns the loads of the first order.

The above aim is achieved in accordance with the invention in such a way that the second balancing means are arranged to rotate around the second immobile joint in a direction opposite to the direction of rotation of the balancing means, in order to decrease or cancel out at least the vertical inertial forces of mass generated by the first order of the periodic motion of the link mechanism, that is, at the operating frequency of the crusher, and that the angular speeds of the balancing means and of the second balancing means are mutually equal.

The invention is described in greater detail in the following, with reference to the accompanying drawings, in which: shows diagrammatically a prior art jaw crusher rocker mechanism provided with a four-link mechanism, and a balancing means (T) rotating with the flywheel,

Figure 1A shows diagrammatically the relationship of the movements of the four- link mechanism shown in Figure 1 to angle φ

Figure 2 shows diagrammatically a jaw crusher rocker mechanism according to the invention provided with a four-link mechanism, a balancing means (T⁺ ) rotating with the flywheel, and a balancing means (T^~ ) rotating at the same speed but in the opposite direction with respect to the previous one, Figure 2A shows design parameters,

Figure 2B shows an adapted pointer presentation of Figure 2A, on the basis of which the dimensioning of the balancing means can preferably be presented,

Figure 3 shows examples of the path of the centre of mass of the rocker mechanism without balancing, of the path with one balancing mass, and of the path of the rocker mechanism balanced with two balancing masses in accordance with the invention,

Figure 4 shows a partial enlargement of Figure 3, showing the path of the centre of mass of the rocker mechanism according to the invention, which is provided with two balancing masses,

Figure 5A shows the resultant of the horizontal inertial force of mass resulting from the movement of the centre of mass moving according to Figures 3 and 4 without balancing and with two balancing masses of the rock- er mechanism according to the invention provided,

Figure 5B shows the resultant of the vertical inertial force of mass resulting from the movement of the centre of mass moving according to Figures 3 and 4 without balancing and with two balancing masses of the rocker mechanism according to the invention provided, and

Figure 5C the resultant of the external moment resulting from the movement of the centre of mass of the rocker mechanism moving according to Fig^¬ ures 3 and 4 and from the rotary movement of the parts of the rocker mechanism without balancing and with two balancing masses of the rocker mechanism according to the invention provided.

Figure 2 thus shows diagrammatically an arrangement for the rocker mechanism of a jaw crusher according to a preferred embodiment of the invention. The invention is not limited merely to a jaw crusher, but can also be applied to other crusher types, such as cone and impact crushers. The jaw crusher is marked with reference numeral 1. The jaw crusher 1 comprises a body 3 which is supported viscoelastically on the base, for example, by means of rubber footing 11 or the like. The body 3 typically comprises walls, in the space limited by which is arranged the first jaw part 4. It is typically a massive plate-like element arranged to be immobile with respect to the body 3. Its operating surface is preferably an obliquely upwards (in Figure 2, obliquely from the bottom upwards when going to the left) extending surface.

The jaw crusher 1 further comprises a rocker mechanism 2 arranged in conjunction with the body 3, the rocker mechanism being formed by the link mechanism 5. In this embodiment, the link mechanism 5 is a four-link mechanism, the two end joints of ^hieh marked with reference numerals 0 (so=called^'origo) and^"D7are arranged to be immobile with respect to the body 3. In this case, between the two mobile joints A and B (the two centremost joints) is arranged, in a manner known as such, a second jaw part 6 forming the rocker of the jaw crusher 1. Of the mobile joints A and B of the link mechanism 5, the first A (in Figure 2 the upper mobile joint A) is arranged as an eccentric shaft in periodic motion around link O which is immobile with respect to the body 3. In other words, the first mobile joint A is arranged to rotate around the immobile joint O. This structure and operation of the eccentric shaft for effecting the movement of the rocker is known as such from previously known jaw crushers and does not, therefore, need to be discussed in any greater detail herein. It should be noted that, for example, one known eccentric shaft structure is realised by means of bearings. The lower mobile joint B shown in Figure 2 is connected by means of a so-called pusher plate 16 to the lower (in the Figure) immobile joint D. Therefore, the period^¬ ic motion of the first mobile joint A around the first immobile joint O determines the paths of both the rocker 6, the lower mobile joint B and the pusher plate 16. The balancing means T⁺ are arranged in connection with the flywheel 7 provided in con- junction with the first immobile joint O. The balancing means T⁺ can also be ar^¬ ranged otherwise than in a flywheel, for example, they can be arranged to rotate in one direction on a balancing shaft or the like arranged in conjunction with the said immobile joint (shaft) O or a shaft parallel to it. In connection with the joint O are arranged power transmission means, such as an electric motor 8 and a drive belt 9, in a manner known as such, by means of which the four-link mechanism 5 can be brought into periodic motion at the desired angular velocity ω.

In order to understand the principles of the invention better, the prior art Figures 1 and 1A are now returned to, wherein, when the jaw crusher 1 is in operation, the body 3 performs an oscillating motion, which generates horizontal and vertical forces on the base and a moment rocking the body of the crusher back and forth. The load generated on the body by the motion of the crusher mechanism may be combined into a resultant (F_x,F_y,M) , for example, at the centre of mass C of the body. Since the motion of the mechanism is periodic with respect to the angle φ (see Figure 1A), and the period is 2π , also the loads generated by the four-link mechanism 5 can be developed into a Fourier series with respect to the angle φ . The load can then be thought to consist of the loads of the first order, which have an effect at the operating frequency of the machine, of loads of the second order, which have an effect at a frequency twice the operating frequency of the machine, etc. In practice, the loads of the first order are clearly the most significant loads exerted by the crusher mechanism on the body 3.

The horizontal and vertical components of the position vector of the centre of mass of the four-link mechanism 5 with respect to a coordinate system where origo is at point O (first immobile joint O), are of the form

R_r = constant + ^_]x cos(^ + ^_lx) + ^2x ^cos(2^ + 6^,2 ) ⁺ " ^" C¹) R_v = constant + ^_l cos(^ + ^_1>,) + ^_{2 v} COS(2^ + ^2_r) + " - (²) and its angular momentum with respect to point O is of the form

L₀ = constant + A₁ COS(^ + θγ ) + A ₂ COS(2^ + θ₂) + · · · (3)

The constants Α_1χ, Α_1γ,θ_ΙΧ,θ_{1 ν}, Α_2χ,Α_{2 ν},θ_2χ,θ_2γ,... and Α_ι,θ_ι, Α₂,θ₂,... in equa^¬ tions (1) - (3) can be calculated numerically by applying the general principles of mechanics, when the values for the geometrical quantities and mass quantities of the four-link mechanism are known. By means of equations (1) - (3) can be calculated the forces and moment generated by the motion of the four-link mechanism. If the total mass of the four-link mechanism 5 is M , the movement of the four-link mechanism generates the horizontal and vertical forces (φ = ω )

F_x = -MR_X = φ²Μ[Α_1χ COS(^ + θ_1χ) + 4A_2x οο$(2φ + θ_2χ) + · - ·] (4)

MR_V <βΜ[Α _γ ζοκ(φ 0_{l v}) 4Α₂ ∞$(2φ 6>₂ and the moment with respect to point 0

M₀ = -L₀ = φ² ^i sin(^ + 0_j) + 2^₂ sin(2^ +0₂) + - --] (6) Loads (4) - (6) are thus carried by the fixing points of the rocker mechanism when the machine is in operation. These loads can be decreased by mounting balancing means in the mechanism.

The rocker mechanism of a jaw crusher is conventionally balanced with one balancing mass T mounted on the flywheel and rotating with it (Figure 1). Even at best, in this way the component of the inertial force of the rocker occurring at the operating frequency of the machine can essentially only be eliminated either in the horizontal direction, whereby the term Α_1χ α$(φ + θ_Χχ) in equation (4) is eliminated, or in the vertical direction, whereby the term A_iy cosW + 9_iy) in equation (5) is eliminated.

Alternatively, a widely used compromise can be made, where some of both the hor- izontal and vertical force is eliminated. The moment (6) rocking the crusher cannot be effected by this. This type of balancing is, however, incomplete and after balancing significant inertial forces and a moment are still exerted on the body 3 of the crusher, especially at the operating frequency of the machine, that is, loads of the first order.

In the invention disclosed herein are used two balancing masses (Figure 2). In this case, in conjunction with the body of the jaw crusher 1 is arranged a second flywheel 70 which is provided with second balancing means T^~ rotating with the sec- ond flywheel 70 in a direction opposite to the direction of rotation of the first flywheel 7, the second balancing means here being a second balancing mass. The second balancing means T^~are arranged to rotate around a second immobile joint

P2. Similarly, the second balancing means ^_ can also be arranged otherwise than in the flywheel 70, for example, they can be arranged to rotate on a balancing shaft or the like arranged in conjunction with the said second immobile joint P2 or a shaft parallel to it. The location of the balancing means J^" rotating in the opposite direction is, for example, at a distance behind the jaw part 4 of the crusher 1 arranged to be immobile. The first balancing means T⁺ rotate with the flywheel 7 in the same direction as the flywheel and at the same angular speed ω. The second balancing means T^~ rotate with the second flywheel 70 at the same angular speed ω, but in the opposite direction with respect to the flywheel 7. In a preferred embodiment of the invention, it is also conceivable that the balancing means 7 ⁺ and the second balancing means J- can be arranged to rotate coaxially in conjunction with the arranged joints O and P2 or shafts (balancing shafts) parallel with them, in opposite directions. This makes the structure compact. The magnitudes, phase angles and locations of the masses of the balancing means J⁺ and T^{^} are dimensioned in such a way that at least the terms of the first order Α_1χ οο&(φ +Θ_1χ) , A_ly cos(^ + ^_{1 (}) in equations (4) and (5), and preferably the term A₁ sin(^ +<9_j) in equation (6) are cancelled out accurately. In this way, the balanced four-link mechanism 5 exerts the following loads on its surroundings

(bal)

<f>²M^(bc" ⁴4? cos(2^ + 6¾^{a )} ) + - " (7)

2Α^^αί) ύνι(2φ + θ (9)

Therefore, the lowest frequency at which the mechanism loads its surroundings is twice the rotational frequency of the machine. The magnitudes of the loads are, in addition, very small compared to the initial ones, because the Fourier series of the loads generated by the four-link mechanism 5 converge rapidly.

In the foregoing is, therefore, only presented an advantageous proof of how the loads and moments of the first order can be eliminated, or at least essentially eliminated, when in addition to single balancing means T ⁺ , the jaw crusher 1 is provided with second balancing means T^~ , In the following is described, with reference to Figures 2A and 2B, how the loads and moments can be eliminated, or at least essentially eliminated. In the present case, this is carried out through the design of the first balancing means T⁺ (or mass) and the second balancing means T^"~(or mass).

The design parameters of the balancing means T⁺ are the magnitude of mass m⁺ , the radius of gyration e⁺ and the phase angle φ⁺ counter-clockwise from direction OA. If so desired, the design parameter φ⁺ can be selected to be clockwise from direction OA. The design parameters of the balancing means T^~ are correspondingly m^~ , e^~ and φ^~~ . Furthermore, the coordinates X_P2, Y_P2 of the centre P2 of the circular orbit of the balancing means T^~ with respect to the coordinate system Oxy are design parameters. The design parameters are shown in Figure 2A, where line segment OA is shown in its horizontal position.

It is mathematically most convenient to describe the design parameters of the balancing masses by means of the complex pointers shown in Figure 2B. By means of the principles of mechanics and the Fourier series it can be shown that if the com- plex pointers A⁺ = β⁺β'^φ+ and A^" = e^~e¹^ (see Figure 2B) of the balancing masses m⁺ and m^~ are determined from the formulae

(11),

then the terms Α_1χ οο$,(φ +Θ_1χ) and ^_1>; cos(^ + 0_{l v},)of the first order of the horizontal and vertical forces F_x and /^generated by the four-link mechanism are cancelled out by the effect of the balancing masses. It can be seen that equations (10) and (11) only determine the products m⁺e⁺ and m^~e^~ .

By means of the principles of mechanics and the Fourier series it can further be shown that the term A_x sin(^ +θ_λ) of the first order of the moment M₀ rocking the crusher is cancelled out by the effect of the balancing mass m ^~ if the pointer of the centre P2 of the circular orbit of the balancing mass m^~ is

1 „' {θ +Φ^~)

(12) m e when the balancing mass m circulates the circular orbit around point O. In equation (12), the pointer of the centre P2 can be presented in the form ;¾ = R₀e'^° . Final expressions are now obtained for the parameters of the balancing masses (see equations (10), (11) and (12))

m⁺e^& = mod (m⁺A⁺) , (f>⁺ = arg(m⁺A⁺) (13) m^~e^~~ = mod(m^~A^~) , φ^~~ = arg(m^~A^~) (14)

R₀ = mod(/-₀) , <A₀ = arg(r₀) (15) where mod( ) is the length and arg( ) the phase angle of the complex pointer. The balancing of the first order is achieved perfectly, when the balancing is carried out in accordance with equations (13) - (15). Using these formulae requires that the terms of the first order of the Fourier series of the position vectors of the horizontal and vertical components of the centre of mass of the four-link mechanism and of the angular momentum of the four-link mechanism are solved numerically in the form shown in equations (1) - (3). The equations for carrying this out are fully known as such, but due to their length they have not been included in this specifica- tion. Alternatively, balancing according to equations (13) - (15) follows by optimising (minimising) the loads F_x, F_y and M.

AN EXAMPLE OF BALANCING

In the following example is shown how force and moment loads of the first order generated by the four-link mechanism can be eliminated by means of two balancing masses rotating in opposite directions.

In the example calculation are used the following typical values for the parameters of a four-link mechanism of a medium-sized jaw crusher. It should be noted that the results obtained are not limited to these values alone, but the values may vary by case. OA = 0.02 m eccentricity of the eccentric shaft

AB = 1.7 m distance between the joints of the rocker

-?£> = 0.6 m distance between the joints of the pusher (toggle) plate

AP₀ = 1.02 m distance component of the centre of mass of the rocker

P₀P = 0.25 m distance component of the centre of mass of the rocker DQo = 0.3 m distance component of the centre of mass of the pusher plate

QoQ = 0.0 m distance component of the centre of mass of the pusher plate

a = 0.30 m horizontal coordinate of joint D with respect to point O b = -1.4 m vertical coordinate of joint D with respect to point O m_e = 1200 kg combined mass of bar OA and the eccentric shaft A m_h = 6000 kg mass of the rocker

m_t = 180 kg mass of the pusher plate I_e = 0.48 kgm² combined moment of inertia of bar OA and the eccentric shaft A

I_h = 3800 kgm² moment of inertia of the rocker

I_t = 5.4 kgm² moment of inertia of the pusher plate With these values, the magnitudes and phase angles of the balancing masses are (with a selected radius of 0.60 m) m⁺ = 201kg, e⁺ = 0.60 m, φ⁺ = -\6Τ m^~ = 78.2 kg, e^~ = 0.60 m, φ^~ = 7Α8° (16) and the distance and direction angle of the centre of the circular orbit of the balancing mass m^~ are

7ζ ^~ 2:58 m, φ₀ =-165 (17)

The above-mentioned masses are overall masses reduced to the vertical sectional plane of the machine (plane of Figure). If the masses are mounted, for example, symmetrically on both sides of the machine, the values of the masses are halved. Should it be desirable to make the balancing mass rotating in the opposite direction more compact, it can be mounted with a radius of, for example, 0.30 m, whereby the mass m^~ required in this example is 156.4 kg. Figure 3 shows a comparison of the path of the centre of mass of the link mechanism 5 defined above without balancing, with single balancing means, and with two balancing means according to the invention (including the balancing masses). The last of these is shown as an enlargement in Figure 4. Figure 3 shows the extent of the path before balancing, which is 21.8 mm in the horizontal direction and 44.6 mm in the vertical direction. Figure 3 further shows, by way of an example, the extent of the path when using single balancing means, as in the prior art. The path of the centre of mass of a link mechanism 5 with two balancing masses according to the invention is shown as a small dot in Figure 3 and enlarged in Figure 4. It can be seen that the extent of the path in the horizontal direction is 0.106 mm and in the vertical direction 0.0621 mm. It can be noted that after balancing, the centre of mass moves extremely little compared to what was previously known, whereby also the inertial forces of mass and the moment decrease markedly. This can be seen in Figures 5A, 5B and 5C, in which are shown the overall forces and moment exerted by the rocker mechanism of the jaw crusher on the surrounding structures without balancing and when balanced with two masses. From Figures 5A, 5B and 5C can be seen that due to the effect of balancing, the highest value of the horizontal force as an absolute value has decreased by 94.3% from a value of 52600 N to a value of 3026 N, by 98.3% from a vertical force value of 105300 N to a value of 1765 N, and by 93.1% from the moment value of 81930 Nm to a value of 5617 Nm. It is further found that the frequency of the loads has doubled (shown also in Figure 4 as an elliptic path appearing twice), as it should, since the loads of the first order, that is, loads occurring at the operating frequency of the machine, have been cancelled out by balancing masses rotating in opposite directions. Com- pared-to the ease that-the rocker mechanism is balanced by using a single balancing mass, as is done in current machines, by balancing with two masses, as disclosed herein, 80-90% greater decreases in the inertial forces and moment are achieved. This is thus a significant decrease compared to that achieved with the prior art balancing means, which cannot be achieved with single balancing means. Accurate values must be calculated, and can be calculated, for example, in the manner disclosed above, separately in the case of each machine. It should be noted separately that the centre P2 of the circular orbit of the balancing mass T^_ can be moved in the horizontal and/or vertical direction without at all or essentially affecting the decrease in the horizontal inertial forces of mass F_x and vertical inertial forces of mass F_y. Horizontal and/or vertical transfer of the centre P2 only affects the moment M oscillating the body 3. Locating the centre P2 at any other point than the optimal point shown in the Figures by way of an example may increase the moment M rocking the body 3 compared to the optimal situation. Despite this, the moment M usually remains considerably lower compared to the prior art. It may be noted that by means of the above invention, the balancing of the rocker mechanism of a jaw crusher can be carried out considerably better, whereby the high inertial forces and moment generated by the motion of the massive rocker mechanism can be eliminated almost completely, or at least reduced to a fraction, approximately to 1/5 to 1/15 part compared to the prior art, whereby the level of oscillation of the machine can be decreased considerably. The decreased level of oscillation reduces malfunctions, heating up of the rubber footing, fatigue fractures and noisiness and lengthens the service life of the machine and allows exceeding of the lowest oscillation resonance, thus making it possible to increase the operating speed of the machine and the production of crushed stone. It may also be possible to decrease the mass of the machine at some point, and the rubber footing 11 will not have to be dimensioned as accurately.

The present invention is not limited to the embodiment described, but may be applied in many ways within the scope of protection specified by the claims.

Claims

1. An arrangement for a rocker mechanism (2) of a crusher, especially a jaw crusher (1), the crusher (1) comprising a body (3), a first jaw part (4) arranged in an immo- bile manner on the body (3), a link mechanism (5) arranged in conjunction with the body (3), the mechanism comprising a second jaw part (6) forming a rocker, the second jaw part being arranged to move alongside the first jaw part (4), between two mobile joints (A, B) of the link mechanism (5), the first of the mobile joints (A) being made into an eccentric shaft which is in periodic motion around the joint (O) which is immobile with respect to the body (3), and in conjunction with which body

(3) are provided balancing means (T ⁺ ) arranged to rotate around the immobile joint (O) or a shaft parallel with it in one direction, and which body (3) is provided with at least a second joint (P2) immobile with respect to the body (3), in conjunction with which are provided second balancing means ( T^~) arranged to rotate around the second immobile joint (P2) in a direction opposite to the direction of rotation of the balancing means (T ⁺ ) in order to decrease or cancel out at least the horizontal inertia! forces of mass (F_x) generated by the first order of the periodic motion of the link mechanism (5), that is, at the operating frequency of the crusher, characterised in that the second balancing means (T^~) are arranged to rotate around the second immobile joint (P2) in a direction opposite to the direction of rotation of the balancing means (T ⁺ ), in order to reduce or cancel out at least the vertical inertial forces of mass (F_y) generated by the first order of the periodic mo^¬ tion of the link mechanism (5), that is, at the operating frequency of the crusher, and that the angular speeds (ω) of the balancing means (T ⁺ ) and of the second balancing means (T^~) are mutually equal.

2. An arrangement as claimed in claim 1, characterised in that the link mechanism (5) is a four-link mechanism, the end joints (O, D) of which are arranged to be immobile with respect to the body (3).

3. An arrangement as claimed in claim 1 or 2, characterised in that the said sec^¬ ond immobile joint (P2) is arranged in conjunction with the body (3) in such a way that the first jaw part (4) remains in the area between the said immobile joint (O) and the second immobile joint (P2).

4. An arrangement as claimed in any of the claims 1 to 3, characterised in that the second immobile joint (P2) is arranged in conjunction with the body (3) at such a point with respect to the first immobile joint (O) where the moment (M) rocking the body (3) is cancelled out completely or partly.

5. An arrangement as claimed in any of the claims 1 to 4, characterised in that the periodic motion of the link mechanism (5) generated by the first mobile joint (A) in periodic motion and the periodic motion of both the balancing means (T ⁺ ) and the second balancing means (T-) are developed into a Fourier series, on the basis of which the inertial forces of mass (F_x and F_y) of the first order of the periodic motion of the link mechanism (5), that is, the inertial forces occurring at the operating frequency of the machine, can be decreased or cancelled out, and the moment (M) of the first order, that is, the moment occurring at the operating frequency of the machine rocking the body (3), can be decreased or cancelled out.

6. An arrangement as claimed in any of the claims 1 to 5, characterised in that the inertial forces of mass (F_x and F_y) of the first order of the periodic motion of the link mechanism (5) generated by the first mobile joint (A) in periodic motion, that is, the inertial forces occurring at the operating frequency of the machine, can be decreased or cancelled out, and the moment (M) of the first order of the periodic mo^¬ tion, that is, the moment occurring at the operating frequency of the machine rocking the body (3), can be decreased or cancelled out by optimising the link mechanism (5), the balancing means (T⁺ ) and the second balancing means (T^~).

7. An arrangement as claimed in any of the claims 1 to 6, characterised in that the balancing means (T ⁺ ) and the second balancing means (T^~) are made of a balancing mass and a second balancing mass which are of different sizes and/or the distances of which from the centre of the circular orbits, that is, the radii e^~ ) and/or the phase angles (φ⁺, φ^~~ ) of the rotary motion are unequal.

8. An arrangement as claimed in any of the claims 1 to 7, characterised in that in conjunction with the said immobile joint (O) or a shaft parallel to it are arranged balancing means (T ⁺ ) rotating in one direction, having the same angular velocity as the eccentric shaft.

9. An arrangement as claimed in any of the claims 1 to 7, characterised in that in conjunction with the said immobile joint (O) or a shaft parallel to it is arranged a balancing shaft or the like, which is provided with balancing means (T ⁺ ) rotating in one direction with the balancing shaft or the like, having the same angular velocity as the eccentric shaft.

10. An arrangement as claimed in any of the claims 1 to 9, characterised in that in conjunction with the said second immobile joint (P2) is arranged a flywheel (70) which is provided with balancing means (T^~ ) rotating in one direction with the flywheel (70), having the same angular speed as the eccentric shaft.

11. An arrangement as claimed in any of the claims 1 to 9, characterised in that in conjunction with the said second immobile joint (P2) is arranged a balancing shaft or the like, which is provided with balancing means (T^~) rotating in one direction with the balancing shaft or the like, having the same angular speed as the eccentric shaft.

12. An arrangement as claimed in any of the claims 1 to 11, characterised in that the balancing means (T⁺ ) and the second balancing means (T^~) are arranged to rotate coaxially in conjuntion with the immobile joint (O) and/or the second immobile joint (P2) and/or correspondingly with shafts parallel to them in opposite direc- tions.