CA1171399A - Hammers (beaters) for fiberising mills (vertical shaft impact crushers) - Google Patents
Hammers (beaters) for fiberising mills (vertical shaft impact crushers)Info
- Publication number
- CA1171399A CA1171399A CA000384632A CA384632A CA1171399A CA 1171399 A CA1171399 A CA 1171399A CA 000384632 A CA000384632 A CA 000384632A CA 384632 A CA384632 A CA 384632A CA 1171399 A CA1171399 A CA 1171399A
- Authority
- CA
- Canada
- Prior art keywords
- shaft
- hammer
- head
- wear resistant
- coupling end
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Earth Drilling (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The invention relates to a beater, also known as a hammer, for use in vertical shaft impact crushers, also known as fiberiser mills, to crush asbestos ore and release the asbestos fibers. The hammer comprises an elongated shaft having a coupling end and a free end opposite the coupling end, and a wear resitant head adjacent the free end of the shaft and extending along a major portion there-of towards the coupling end. This two-piece construction enables one to select for the shaft a material providing the necessary tensile strength and elongation independently of the material used for the wear resistant head to provide the necessary hardness and wear resistance required for the hammer head.
The invention relates to a beater, also known as a hammer, for use in vertical shaft impact crushers, also known as fiberiser mills, to crush asbestos ore and release the asbestos fibers. The hammer comprises an elongated shaft having a coupling end and a free end opposite the coupling end, and a wear resitant head adjacent the free end of the shaft and extending along a major portion there-of towards the coupling end. This two-piece construction enables one to select for the shaft a material providing the necessary tensile strength and elongation independently of the material used for the wear resistant head to provide the necessary hardness and wear resistance required for the hammer head.
Description
1~7~L3~9 The present invention relates to hammers of the type used in fiberising mills for the production of asbestos fibers.
Hammers of such type generally have an elongated shaft provided at a free end thereof with a head adapted to crush asbestos rocks. The shaft must have sufficient tensile strength to withstand the revolutionary force to which it is normally subjected (for example, an average of 1 000 rpm on a 4 feet radius) while having sufficient elongation to withstand the shock it receives from the continuous barrage of rocks being crushed. A minimum elongation is required in order to overcome the shock and thus prevent breakage of the shaft. On the other hand, the head itself must be of sufficient hardness to withstand the continuous abrasion to which it is subjected. One therefore, requires a wear-resistant material for the head so as to provide maximum working life.
In existing hammers, the shaft and head are cast as a one-piece tool made of only one materialO To ensure the shaft does not fracture in operation, a material having sufficient elongation and tensile strength is selected.
This material has a low hardness and wear resistance because of the properties it was selected for, resulting in the rapid wear of the head. As a result of such rapid wear, the hammers have to be changed at short intervals resulting in high stoppage time and manhours.
It is the object of this invention to obviate to the above problem and to provide a hammer which has a much greater working life and thus saves stoppage time and manhours. The hammer must therefore overcome the clash ,,; ~
~7~399~
between the requirements of tensile strength and elongation and those of hardness and wear resistance.
In accordance with the present invention, there is thus provided a hammer for use in fiberising mills for the production of asbestos fibers, comprising an elongated shaft having a coupling end and a free end opposite the coupling end, and a wear resistant head adjacent the free end of the shaft and extending along a major portion thereof towards the coupling end.
A hammer in accordance with the invention is therefore a two-piece construction in which the wear resistant head extends along a major portion of the shaft.
This two-piece construction enables one to use on the one hand any material which provides the necessary tensile strength and elongation to the shaft and, on the other hand, any material which provides the necessary hardness and wear resistance to the wear resistant head.
A preferred embodiment of the invention will now be described in greater detail with reference to an example thereof as illustrated in the accompanying drawings, in which:
Figure 1 is a side elevation view of a hammer for use in the production of asbestos fibers, according to the prior art;
Figure lA is an end elevation view of the hammer illustrated in Figure 1:
Figure 2 is a part sectional side elevation view of a hammer according to a preferred embodiment of the invention, Figure 2A is an end elevation view of the hammer illustrated in Figure ~;
~:17~399 Figure 3 is a side elevation showing the shaft used in the embodiment represented in Figure 2, and Figure 3A is an end elevation view of the shaft illustrated in Figure 3.
Referring first to Figure 1, there is shown a prior art hammer which consists of a one-piece cast tool comprising an elongated shaft 10 and a head 12. The other end 16 of the shaft serves as a coupling end and is provided with an eyelet 18 for coupling the shaft 10 to drive means (not shown) adapted to rotate the hammer. As best shown in Figure lA, the head 12 is rectangular in cross-section and is provided with two longitudinally extending grooves 20 and 20', one on each of the opposed surfaces 22 and 22'.
The grooves 20 and 20' are located on the surfaces 22 and 22' so as to provide two working impact surfaces 20,24 and 20~,24~ Since the shaft 10 and the head 12 are one-piece cast and are thus made of the same cast material which cannot meet at the same time the necessary requirements of tensile strength and elongation for the shaft and those of hardness and wear resistance for the head, the head wears rapidly resulting in frequent stoppage and high manhours.
In order to overcome this problem, the wear resistant head is made secured over the shaft, thereby enabling one to select for the wear resistant head a material providing the necessary hardness and wear resistance inde-pendently of the material used for the shaft to provide the necessary tensile strength and elongation. ~hus, in the preferred embodiment of the invention illustrated in Figure 2, a wear resistant head 112 is provided which is secured over a major portion of the shaft 102. The shaft 102 has a ~7I399 coupling end 104 provided with an eyelet 106, an inwardly tapering ~ead section 108 adjacent its free end and a straight support section 110 contiguous to the head section 108, as best shown in Figure 3, the head section 108 gradually tapers towards the coupling end 104 so as to assist the wear resistant head 112 to remain attached to the shaft.
me wear resistant head 112 which extends entirely over the head section 108 of the shaft defines the hammer head.
As shown in Figure 2A, the wear resistant head 112 has substantially the same cross-sectional con~iguration as the prior art head 12 illustrated in Figure lA, and is thus rectangular in cross-section and is similarly provided with two longitudinally extending grooves 116 and 116' one on each of the opposed outer surfaces 118 and 118', The grooves 116 and 116' are disposed on the surfaces 118 and 118' so as to also provide two working impact surfaces 116,120 and 116',120'. The head section 108 of the shaft has a cross-section of substantially the same configuration as the wear resistant head 112 and is provided with two longitudinally extending grooves 122 and 122', as best shown in Figure 3A. The head section 108 is symmetrically disposed within the wear resistant head 112, the ~aper of the head secti~n 108 of the shaft assisting in the anchorage of the wear resistant head 112 onto the shaft 102.
As already mentioned, the shaft may be made of any material which provides the necessary tensile strength and elongation and the head of any material which provides the necessary hardness and wear resistance. With respect to the known required properties, the shaft 102 should have a tensile strength of at least 20 tons per square inch and an ,~
~ - 4 -~17~3~9 elongation of at least 8%.
On the other hand, the wear resitant head 112 should have a hardness of at least 350 Brinnell. As examples of suitable materials, one may use for the shaft spheroidal graphite cast iron having a tensile strength of 27 tons per square inch and an elongation of 12% and, for thé wear resistant head, Ni-hard cast iron type 2-hi strength (ASTM specification A532 1 - 13) with a Brinell hardness of 550.
Using the above materials, a hammer as illustrated in Figure 2 was made by first casting the shaft 102 and then casting thereonto the wear resistant head 112, according to the conventional casting procedures for the materials utilized. The resulting hammer was thereafter stress relieved at 450C for 8 hours. This treatment overcomes the stresses that were induced in the shaft when the wear resistant head was cast onto the shaft. The hammer so manufactured has proven to be very successful in that it has a life tirne of up to five times longer that any known or existing hammer, while marketed at a competitive price.
Hammers of such type generally have an elongated shaft provided at a free end thereof with a head adapted to crush asbestos rocks. The shaft must have sufficient tensile strength to withstand the revolutionary force to which it is normally subjected (for example, an average of 1 000 rpm on a 4 feet radius) while having sufficient elongation to withstand the shock it receives from the continuous barrage of rocks being crushed. A minimum elongation is required in order to overcome the shock and thus prevent breakage of the shaft. On the other hand, the head itself must be of sufficient hardness to withstand the continuous abrasion to which it is subjected. One therefore, requires a wear-resistant material for the head so as to provide maximum working life.
In existing hammers, the shaft and head are cast as a one-piece tool made of only one materialO To ensure the shaft does not fracture in operation, a material having sufficient elongation and tensile strength is selected.
This material has a low hardness and wear resistance because of the properties it was selected for, resulting in the rapid wear of the head. As a result of such rapid wear, the hammers have to be changed at short intervals resulting in high stoppage time and manhours.
It is the object of this invention to obviate to the above problem and to provide a hammer which has a much greater working life and thus saves stoppage time and manhours. The hammer must therefore overcome the clash ,,; ~
~7~399~
between the requirements of tensile strength and elongation and those of hardness and wear resistance.
In accordance with the present invention, there is thus provided a hammer for use in fiberising mills for the production of asbestos fibers, comprising an elongated shaft having a coupling end and a free end opposite the coupling end, and a wear resistant head adjacent the free end of the shaft and extending along a major portion thereof towards the coupling end.
A hammer in accordance with the invention is therefore a two-piece construction in which the wear resistant head extends along a major portion of the shaft.
This two-piece construction enables one to use on the one hand any material which provides the necessary tensile strength and elongation to the shaft and, on the other hand, any material which provides the necessary hardness and wear resistance to the wear resistant head.
A preferred embodiment of the invention will now be described in greater detail with reference to an example thereof as illustrated in the accompanying drawings, in which:
Figure 1 is a side elevation view of a hammer for use in the production of asbestos fibers, according to the prior art;
Figure lA is an end elevation view of the hammer illustrated in Figure 1:
Figure 2 is a part sectional side elevation view of a hammer according to a preferred embodiment of the invention, Figure 2A is an end elevation view of the hammer illustrated in Figure ~;
~:17~399 Figure 3 is a side elevation showing the shaft used in the embodiment represented in Figure 2, and Figure 3A is an end elevation view of the shaft illustrated in Figure 3.
Referring first to Figure 1, there is shown a prior art hammer which consists of a one-piece cast tool comprising an elongated shaft 10 and a head 12. The other end 16 of the shaft serves as a coupling end and is provided with an eyelet 18 for coupling the shaft 10 to drive means (not shown) adapted to rotate the hammer. As best shown in Figure lA, the head 12 is rectangular in cross-section and is provided with two longitudinally extending grooves 20 and 20', one on each of the opposed surfaces 22 and 22'.
The grooves 20 and 20' are located on the surfaces 22 and 22' so as to provide two working impact surfaces 20,24 and 20~,24~ Since the shaft 10 and the head 12 are one-piece cast and are thus made of the same cast material which cannot meet at the same time the necessary requirements of tensile strength and elongation for the shaft and those of hardness and wear resistance for the head, the head wears rapidly resulting in frequent stoppage and high manhours.
In order to overcome this problem, the wear resistant head is made secured over the shaft, thereby enabling one to select for the wear resistant head a material providing the necessary hardness and wear resistance inde-pendently of the material used for the shaft to provide the necessary tensile strength and elongation. ~hus, in the preferred embodiment of the invention illustrated in Figure 2, a wear resistant head 112 is provided which is secured over a major portion of the shaft 102. The shaft 102 has a ~7I399 coupling end 104 provided with an eyelet 106, an inwardly tapering ~ead section 108 adjacent its free end and a straight support section 110 contiguous to the head section 108, as best shown in Figure 3, the head section 108 gradually tapers towards the coupling end 104 so as to assist the wear resistant head 112 to remain attached to the shaft.
me wear resistant head 112 which extends entirely over the head section 108 of the shaft defines the hammer head.
As shown in Figure 2A, the wear resistant head 112 has substantially the same cross-sectional con~iguration as the prior art head 12 illustrated in Figure lA, and is thus rectangular in cross-section and is similarly provided with two longitudinally extending grooves 116 and 116' one on each of the opposed outer surfaces 118 and 118', The grooves 116 and 116' are disposed on the surfaces 118 and 118' so as to also provide two working impact surfaces 116,120 and 116',120'. The head section 108 of the shaft has a cross-section of substantially the same configuration as the wear resistant head 112 and is provided with two longitudinally extending grooves 122 and 122', as best shown in Figure 3A. The head section 108 is symmetrically disposed within the wear resistant head 112, the ~aper of the head secti~n 108 of the shaft assisting in the anchorage of the wear resistant head 112 onto the shaft 102.
As already mentioned, the shaft may be made of any material which provides the necessary tensile strength and elongation and the head of any material which provides the necessary hardness and wear resistance. With respect to the known required properties, the shaft 102 should have a tensile strength of at least 20 tons per square inch and an ,~
~ - 4 -~17~3~9 elongation of at least 8%.
On the other hand, the wear resitant head 112 should have a hardness of at least 350 Brinnell. As examples of suitable materials, one may use for the shaft spheroidal graphite cast iron having a tensile strength of 27 tons per square inch and an elongation of 12% and, for thé wear resistant head, Ni-hard cast iron type 2-hi strength (ASTM specification A532 1 - 13) with a Brinell hardness of 550.
Using the above materials, a hammer as illustrated in Figure 2 was made by first casting the shaft 102 and then casting thereonto the wear resistant head 112, according to the conventional casting procedures for the materials utilized. The resulting hammer was thereafter stress relieved at 450C for 8 hours. This treatment overcomes the stresses that were induced in the shaft when the wear resistant head was cast onto the shaft. The hammer so manufactured has proven to be very successful in that it has a life tirne of up to five times longer that any known or existing hammer, while marketed at a competitive price.
Claims (9)
1. A hammer also known as a beater for use in vertical shaft impact crushers also known as fiberiser mills, for the production of asbestos fibers, said hammer comprising an elongated shaft having a coupling end and a free end opposite said coupling end, and a wear resistant head adjacent said free end of said shaft and extending along a major portion thereof towards said coupling end.
2. A hammer as claimed in claim 1, wherein said shaft further has a head section adjacent said free end and a support section contiguous to said head section, and wherein said wear resistant head extends entirely over said head section of said shaft.
3. A hammer as claimed in claim 2, wherein said head section of said shaft gradually tapers towards said coupling end so as to assist said wear resistant head to remain attached to said shaft.
4. A hammer as claimed in claim 3, wherein said wear resistant head tapers towards said coupling end of said shaft.
5. A hammer as claimed in claim 1, wherein said wear resistant head has a rectangular cross-section and is provided with two longitudinally extending grooves, one on each of opposed outer surfaces of said wear resistant head, said grooves being each disposed on a respective surface so as to provide a respective working impact surface.
6. A hammer as claimed in claim 1, wherein said shaft is made of a material having a tensile strength of at least 20 tons per square inch and an elongation of at least 8%.
7. A hammer as claimed in claims 1 or 6, wherein said wear resistant head is made of a material having a hardness of at least 350 Brinnell.
8. A hammer as claimed in claim 1, wherein said shaft is made of spheroidal graphite cast iron having a tensile strength of 27 tons per square inch and an elongation of 12%.
9. A hammer as claimed in claim 1, made by first casting said shaft, then casting onto said cast shaft said wear resistant head and thereafter stress relieving the resulting hammer at a temperature of 450°C for about 8 hours.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000384632A CA1171399A (en) | 1981-08-26 | 1981-08-26 | Hammers (beaters) for fiberising mills (vertical shaft impact crushers) |
| AU86790/82A AU8679082A (en) | 1981-08-26 | 1982-08-05 | Hammer for hammer mill |
| ZA825785A ZA825785B (en) | 1981-08-26 | 1982-08-10 | Hammers for fiberising mills |
| ZW17782A ZW17782A1 (en) | 1981-08-26 | 1982-08-23 | Hammers (beaters) for fiberiser mills (vertical shaft impact crushers) |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000384632A CA1171399A (en) | 1981-08-26 | 1981-08-26 | Hammers (beaters) for fiberising mills (vertical shaft impact crushers) |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1171399A true CA1171399A (en) | 1984-07-24 |
Family
ID=4120799
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000384632A Expired CA1171399A (en) | 1981-08-26 | 1981-08-26 | Hammers (beaters) for fiberising mills (vertical shaft impact crushers) |
Country Status (4)
| Country | Link |
|---|---|
| AU (1) | AU8679082A (en) |
| CA (1) | CA1171399A (en) |
| ZA (1) | ZA825785B (en) |
| ZW (1) | ZW17782A1 (en) |
-
1981
- 1981-08-26 CA CA000384632A patent/CA1171399A/en not_active Expired
-
1982
- 1982-08-05 AU AU86790/82A patent/AU8679082A/en not_active Abandoned
- 1982-08-10 ZA ZA825785A patent/ZA825785B/en unknown
- 1982-08-23 ZW ZW17782A patent/ZW17782A1/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| AU8679082A (en) | 1983-03-03 |
| ZW17782A1 (en) | 1983-01-19 |
| ZA825785B (en) | 1983-06-29 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEC | Expiry (correction) | ||
| MKEX | Expiry |