GB2210290A

GB2210290A - Beater unit

Info

Publication number: GB2210290A
Application number: GB8817991A
Authority: GB
Inventors: Werner Sauermann; Hardy Hochgraef
Original assignee: Nagema VEB
Current assignee: Nagema VEB
Priority date: 1987-09-29
Filing date: 1988-07-28
Publication date: 1989-06-07
Anticipated expiration: 2008-07-28
Also published as: DE3822552C2; GB8817991D0; NL8801909A; DE3822552A1; GB2210290B; CH676803A5; DD265083A1

Description

cl 6,1 z 4 10 2 9 0 - 1 BEATER UNIT The present invention relates to a

beater unit, especially for a hammer mill used in, for example, the communition of foodstuffs in the mixed food industry and agriculture.

In some known hammer mills, areally constructed or flat beaters are pivotally arranged concentrically in ordered succession around a rotor axis. The high circumferential speeds of the beaters, which are required for communition, economic in energy, of foodstuffs and the relatively high wear of the beating edges oblige a constructive compromise with reference to substantiality of the beater edges depend- ing on the nature of the constituent material of the beaters, pivot ability to provide mechanical overload protection and ignition source avoidance, absorption of the high radial and circumferential forces of the beaters, and ease of exchange. In general, one or two bores is or are arranged in the beater symmetrically to the axis which passes through the centre of gravity of the beater and this bore or these bores serves or serve for the reception of the beater bolt, which in turn is guided and axially secured in receiving bores of rotor discs.

In the case of beater units disclosed in DE-OS 29 35 768 and DE-OS 30 11 427, the placing in readiness of a new beating edge after changing the rotational direction of the rotor is possible only through slinging over of the beaters of the entire beater unit The cross, section of the bar on which the beaters are arranged is matched to the bores in the beaters. Although the beater unit fulfils all require- ments in respect of function and life and its manufacture is relatively simple, the slinging over of the beater represents a high physical load for operating personnel and needs a certain skill.

There are also beater units in which the bores in the beater are constructed, relative to a slot interconnecting the bores, symmetrically to its longitudinal axis or axes in the case of flat beaters with more than four beating edges and with or without narrowing of the crosssection. The object of this arrangement is to allow placing in readiness of a new sharp beating edge without disassembly of the entire beater unit. In conjunction with this there is a reduction in physical load and an increase of the use time of the beater unit.

In the case of beater units disclosed in SU-PS 408 654, SU-PS 367 116, GB 20 35 840 and GB 20 76 310, the geometric shape of the receiving bar for the beaters is adapted partly in the width of the slot without cross-sectional change, partly with cross-sectional change in region of the beater, matched to the number of the beaters per receiving bar. These shapes of the bar in connection with specially constructed beaters make possible the placing in readiness of a new beating edge without disassembly of the bar. However, an unintentional reversal of edges can occur due to wear-induced weight loss of the beater, to overload and in slowing down of the rotor, which leads to imbalance of the rotor during further operations.

A solution is proposed in GB 20 35 840, where spring elements prevent unintentional sliding of the beaters. However, that is aqhieved only if the tightening forces are selected to be appropriately high. This gives rise to the disadvantage that the tightening forces must be so high that sliding of the beater is prevented in the case of contact with a foreign body. Moreover, the beaters can be mounted and demounted only with auxiliary means and thereby the pivotable C 1 - 3 suspension of the beaters is necessarily forfeited.

In DE-PS 29 07 561 C2 there is disclosed a hammer mill with a very large beater unit, in which the mass of the entire beater row so strongly loads the carrier bar that withdrawal of the bar is possible only if the beater set is lifted. A slot arranged in each beater does not have the function of a mounting limitation, but serves as an abutment for the case when lifting of the beater set is necessary. The individual beater has so great an intrinsic mass that, in the case of knocking out of the carrier bar and consequent falling of the beaters into the mill housing, the lifting up and separating of the beaters without assistance requires substantial physical exertion. The device serves, in the case of turning of the beater, as a load receiving means and is rotated only about its vertical axis through 18W; thus only one new beating edge is placed in readiness on the same beating side of the beater.

In WP 230 697 there is disclosed a beater unit with asymmetrical cutout in the beater, and its predetermined boundaries and the crosssectional reduction, shaped corresponding to the boundaries, of the receiving bar including the positional fixing of the zones of the cross-sectional reduction relative to the rotational axis of the rotor, make possible a reversal of the edges of the beater by manual sliding and without positional change or partial assembly between beaters. and bar. Spring elements with smaller tightening forces serve for beater positioning along the bar and for absorption of gravitational forces on slowing down of the beater unit. They have no influence on the achieving and retention of the working position of the beaters.

However, this unit has the disadvantage that in the case of - 4 mechanical lylocking spacer sleeves and of beater trajectories which are offset from beater row to beater row, the cross-sectional changes must be differently arranged in the height of the beaters. This entails greater complication, a smaller degree of standardisation and additional 5 assembly effort for the manufacturer and the user.

If frictional ly-locking spring elements are used, the aforementioned disadvantages do not arise, but the high specific loading of the entire rotor requires special spring elements. In the case of hammer mills with high throughputs and/or a high proportion of foreign bodies, the inevitable wear and spring element loss through fracture leads to the deterioration of the function of the hammer mill, as the beaters can freely move within the rotor discs.

There is thus a need for a beater unit with a mounting bar which can mount beaters with cutouts which have, for example,an asymmetrical shape along their longitudinal axis and so that the beating edges of the beaters may be able to be used in succession without disassembly of the beater unit. The bar should preferably be uniformly desi_gned for all beater rows in a hammer mill able to fix the location of the beaters by spacer sleeves,so that fault-prone special spring elements can be dispensed with. The pendulating movement of the beaters in working position should preferably be kept radial and unintentional reversal of the beating edges prevented. The bar should at the s" time preferably also permit, in the case of preparation of the reverse position, manual reversal of the beating edges without disassembly of the entire beater unit and rotation of the bar into a specific position.

According to the present invention there is provided a beater 1 -11 - 5 unit comprising a mounting bar extending between and retained in bores in two rotary support members, a plurality of beater elements mounted on the bar, and a plurality of spacer sleeves mounted on the bar and arranged between the beater elements to dispose the elements at spacings along the bar, each beater element being provided with a first bearing bore receiving the bar, a second bearing bore spaced from the first bore and arranged to receive the bar in a reversed position of the element and a slide passage interconnecting the bearing bores and having a width smaller than the diameter of each bearing bore, and the mounting bar comprising a carrier element which has a cross-sectional area in the form of a circle reduced by a segment thereby to provide a flat along the length of the bar and minimum diameter of which is substantially equal to the width of the passage in each beater element and a locking element which extends along the flat and is detachably connected to the carrier element and which has line contact with the carrier member and line or area] contact with the sleeves and the walls of the bores in the support members, securing means being provided to secure the bar to one of the support members and releasable to permit relative displacement of the carrier element and the locking element in the axial direction of the bar.

In a preferred embodiment the bar over its entire length comprises a carrier element and a locking element releasable relative to one. another and is centred in working position, ontheinsertion of mechanicallylocking spacer sleeves, by the bore walls of such sleeves and by the bores in rotor discs. The carrier element has the cross-sectiona] shape of a circular area reduced by a segment of a circle and corresponds in its smallest dimension approximately to the width of 1 the passage, for example an asymmetrical cutout, in each beater and is matched with this in the boundary regions. The locking element has such a geometric shape that it has line contact at the contact region between carrier element and locking element and line or areal contact at the contact region between locking element, the bores of the rotor discs and the spacer sleeves, the locking element being connected at at least one end by mechanical or frictional force with the carrier element. An axial/radial securing device engages in grooves of the carrier element and additionally fixes the axial position of the entire bar as well as the radial orientation of the carrier element. The axial/radial securing device is releasably connected with one of the rotor discs.

An embodiment of the present invention will now be more particularly described by way of example with reference to the accompanying drawings, in which:

Fig. 1 is a schematic longitudinal section of part of beater unit embodying the invention, in the direction A of_ Fig. 2; Fig. 2 is an end view of part of the beater unit, in the direction A of Fig. 1; Fig. 3 is a view of part of a carrier element of the beater unit, in the direction B of Fig. 5; Fig. 4 is a view of part of a locking element of the beater unit; and Fig. 5 is an end view of the carrier element in the direction B of Fig. 3.

Referring now to the drawings, there is shown part of a hammer - 7 mill beater unit in which beaters 3 rotate in working position with high circumferential speed on circulatory paths which are determined in their spacing by mechanical ly-locking spacer sleeves 4. The radial and circumferential forces which act, during a comminution process, on the beating edge of each beater 3 are transmitted by a mounting bar, which consists of a carrier element 2 and a locking element 1, to rotor discs 5. Each beater has two bores for selectively supporting the beater on the bar diameter 7 of the carrier element 2, the bores being interconnected by a passage which is disposed asymmetrically of the longitudinal axis of the beater and the width 8a of which is smaller than the diameter 7a of each of the bores. The carrier element 2 has the cross-sectional area of a circle reduced by a segment and its minimum diameter, or height, 8 corresponds approximately to the width 8a of the passage in each beater. The maximum diameter 7 of the bar, consisting of the two elements 1 and 2, corresponds to the bore diameter 7a in the beater.

The locking element 1 has a bent-over portion mechanically coupled with the carrier element 2 by engagement in a groove 9 thereof. The bent-over portion is retained in the groove by an axial/radial securing device 6, which is detachably connected to one of the rotor discs 5 and also engages in a groove 10 in the carrier element 2. The carrier element 2 is thus directly, and the locking element 1 indirectly, set in a fixed position, so that the beater 3 can support itself analogously to the bolt diameter 7. In the case of deflection of the beater 3 by itself through 90', an unintentional reversal of the sides of the beater cannot occur, as the diameter 7 of the bar is greater than the width 8a of the passage in the beater. The spacer 1 1 sleeves 4 and rotor discs 5 centre the two elements 1 and 2 in such a manner that the blocking dimension 7, 7a is maintained and at the same time the locking element 1 is protected from wear and deformation by foreign bodies.

If one of the four beating edges of a beater is worn, the placing in readiness of a new sharp beating edge is required. This takes place, without disassembly and reassembly of the entire beater set, by releasing the device 6 from the rotor disc 5 and removing it from the groove 10, the width of which corresponds to the thickness of the device 6. As the beaters 3 support themselves by way of the bore diameter 7a in the stationary state and in free movability on the bar diameter 7 of the carrier element 2, the locking element 1 is free of any load and can be removed by manual force. Thereafter, the beater 3 is pivoted through 900 and brought into the position in which the passage in the beater 3 and the dimension 8 of the carrier element 2 are mutually aligned. The beater now occupies a push-through position and can be pushed over the carrier element 2 until in its other end position. Independently of which position the beater 3 has relative to the rotor axis after such pushing-through, the centring of the beater 3 secures, by way of the spacer sleeves 4 and the bores of the rotor discs 5, an effortless insertion of the locking element 1. Thereafter, the axiallradial securing device 6 is fastened to the relevant rotor disc 5 and the beater 3 is again operationally ready. When all four beating edges of the beater are worn, the locking element 1, the carrier element 2 and the spacer sleeves 4 must be disassembled. The assembly of new beater sets takes place with a saving of working time in that the spacer sleeves 4 and beaters 3 0 1 are plugged only onto the carrier element and thereafter the locking element 1 and the securing device 6 are fitted.

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Claims

1. A beater unit comprising a mounting bar extending between and retained in bores in two rotary support members, a plurality of beater elements mounted on the bar, and a plurality of spacer sleeves mounted on the bar and arranged between the beater elements to dispose the elements at spacings along the bar, each beater element being provided with a first bearing bore receiving the bar, a second bearing bore spaced from the first bore and arranged to receive the bar in a reversed position of the element and a slide passage interconnect- ing the bearing bores and having a width smaller than the diameter of each bearing bore, and the mounting bar comprising a carrier element which has a cross-sectional area in the form of a circle reduced by a segment thereby to provide a flat along the length of the bar and the minimum diameter of which is substantially equal to the width of the passage in each beater element and a locking element which extends along the flat and is detachably connected to the carrier element and which has line contact with the carrier member and line or area] contact with the sleeves and the walls of the bores in the support members, securing means being provided to secure the bar to one of the support members and releasable to permit relative displace ment of the carrier element and the locking element in the axial direction of the bar.

2. A beater unit as claimed in claim 1, wherein the locking element has a portion engaged in a respective groove in the carrier element.

1

3. A beater unit as claimed in either claim 1 or claim 2, the securing means comprising a securing member detachably connected to said one of the support members and engaged in a respective groove in the carrier element.

4. A beater unit as claimed in any one of the preceding claims, wherein the locking element is of circular cross-section.

5. A beater unit as claimed in any one of claims 1 to 4, wherein the locking element is of elliptical cross-section.

6. A beater unit substantially as hereinbefore described with reference to the accompanying drawings.

1 Published 1988 at The Patent Of.l:ce. State Houss 6671 HiCh Ho"-,:rn. London WC1R 4TP larher ccpies nnky be obtained frcin Tbe Patent C)Ejee.

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