EP2555607A1 - Titanium blade enclosure for a lawnmower - Google Patents
Titanium blade enclosure for a lawnmowerInfo
- Publication number
- EP2555607A1 EP2555607A1 EP10723353A EP10723353A EP2555607A1 EP 2555607 A1 EP2555607 A1 EP 2555607A1 EP 10723353 A EP10723353 A EP 10723353A EP 10723353 A EP10723353 A EP 10723353A EP 2555607 A1 EP2555607 A1 EP 2555607A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- lawnmower
- titanium
- welding
- blade enclosure
- cutting means
- 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.)
- Withdrawn
Links
- 239000010936 titanium Substances 0.000 title claims abstract description 31
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 title claims abstract description 30
- 229910052719 titanium Inorganic materials 0.000 title claims abstract description 28
- 238000003466 welding Methods 0.000 claims abstract description 14
- 238000005520 cutting process Methods 0.000 claims abstract description 7
- 229910000831 Steel Inorganic materials 0.000 claims description 6
- 239000010959 steel Substances 0.000 claims description 6
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 4
- 229910001220 stainless steel Inorganic materials 0.000 claims description 4
- 239000010935 stainless steel Substances 0.000 claims description 4
- 229910001200 Ferrotitanium Inorganic materials 0.000 claims description 3
- 239000011324 bead Substances 0.000 claims description 2
- 238000001816 cooling Methods 0.000 claims description 2
- 238000005238 degreasing Methods 0.000 claims description 2
- 239000012535 impurity Substances 0.000 claims description 2
- 239000011261 inert gas Substances 0.000 claims 1
- 238000010622 cold drawing Methods 0.000 abstract description 2
- 238000004519 manufacturing process Methods 0.000 description 17
- 229910052782 aluminium Inorganic materials 0.000 description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 4
- 238000005452 bending Methods 0.000 description 3
- 239000004035 construction material Substances 0.000 description 3
- 238000003754 machining Methods 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 238000004381 surface treatment Methods 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 230000032683 aging Effects 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- UQZIWOQVLUASCR-UHFFFAOYSA-N alumane;titanium Chemical compound [AlH3].[Ti] UQZIWOQVLUASCR-UHFFFAOYSA-N 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 239000012267 brine Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 150000001735 carboxylic acids Chemical class 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 235000013305 food Nutrition 0.000 description 1
- 229910001608 iron mineral Inorganic materials 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000002161 passivation Methods 0.000 description 1
- 230000007425 progressive decline Effects 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 description 1
- 239000001117 sulphuric acid Substances 0.000 description 1
- 235000011149 sulphuric acid Nutrition 0.000 description 1
- 230000001960 triggered effect Effects 0.000 description 1
- 235000013311 vegetables Nutrition 0.000 description 1
Classifications
-
- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01D—HARVESTING; MOWING
- A01D34/00—Mowers; Mowing apparatus of harvesters
- A01D34/01—Mowers; Mowing apparatus of harvesters characterised by features relating to the type of cutting apparatus
- A01D34/412—Mowers; Mowing apparatus of harvesters characterised by features relating to the type of cutting apparatus having rotating cutters
- A01D34/63—Mowers; Mowing apparatus of harvesters characterised by features relating to the type of cutting apparatus having rotating cutters having cutters rotating about a vertical axis
- A01D34/81—Casings; Housings
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21K—MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS
- B21K19/00—Making articles for agricultural machinery
Definitions
- the present invention relates to a cutting blade enclosure and its manufacturing process, particularly the present invention relates to adoption of titanium as construction material of said blade enclosure.
- a titanium blade enclosure has a mechanical strength, both in terms of ultimate strength and yield strength, slighdy lower but a whole weight lower than 40%, for which reason it is possible to adopt in the titanium blade enclosure greater sections and, all things considered, a strength (or greater if desired) like the steel blade enclosure strength, by keeping a minor weight in respect thereof as well.
- titanium has a weight greater than about 60% but on the other hand it has an almost double strength: essentially by manufacturing the same blade enclosure with titanium, rather than with aluminum, it is possible to adopt thicknesses more than four times smaller, while keeping a noticeable strength, but decreasing the whole weight of the part also down to 50% in respect of the same manufactured with aluminum.
- the surface treatments generally provided for the steel or aluminum blade enclosures for increasing their strength against the structural ageing, or chemical and mechanical etching of the weather are no more needed while adopting titanium, since it is naturally resistant to oxidation, due to the surface passivation just triggered by the oxidizer acids, but also by sulphuric acid, hydrochloric acid, ammonia, alkali, brine, chloride solutions and the most of the carboxylic acids.
- a blade enclosure manufactured with such material keeps its mechanical characteristics intact even after a long exposure to the sun rays or, however, following up even high thermal ranges, which indeed almost slight distortions correspond to.
- the clear absence of surface treatments after machining for manufacture of the part causes the titanium blade enclosure to be wholly recyclable with a subsequent decrease of the environmental impact both during manufacture and disposal at the end of the lawnmower service life.
- the titanium biocompatibility makes the lawnmower blade enclosure completely inert and, therefore, not contaminating thus allowing, in fact recommending, its use especially in areas subject to vegetable cultivations with food purposes and in play grounds.
- Main object of the present invention is therefore to provide a lawnmower blade enclosure obtainable by a manufacturing process in which the used construction material is titanium.
- fig. 1 is a flow diagram showing steps of the manufacturing process of lawnmower titanium blade enclosure according to the present invention.
- step Fl provides the adoption of particular expedients in die design, that is, in respect of a like die for the manufacture of a stainless steel blade enclosure, it will necessary to use greater bending radii R Ti since, for example, for a titanium slab with a thickness of about 2 mm— reference size for this technical field— there is no opportunity to obtain bending radii smaller than about 2,5 mm.
- step F2 as shown in fig. 1 , there is provided a cold drawing operation for the titanium slab: a choice of such machining is suggested by the high ductility offered by titanium— see the percent elongation in the previous mechanical characteristic table— on condition that the drawing pressure values within the press greater than in a like macliining of a steel blade enclosure.
- the step F3 finally, already considered the high spring back of the titanium— see the Young's module in the previous mechanical characteristic table— leads to the complete dimensional recover of the die by means of welding operation or, alternatively, a riveting operation.
- said welding operation in order to obtain joints with the same mechanical and corrosion proofing characteristics of the rest of the die, is a MIG welding carried out according to the following expedients:
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Environmental Sciences (AREA)
- Agronomy & Crop Science (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Soil Working Implements (AREA)
Abstract
A lawnmower having a cutting blade enclosure manufactured by cold drawing a titanium sheet, preferably with a thickness of about 2 mm, and subsequently welding (or riveting) joints for dimensional recover of the formed blade enclosure.
Description
TITANIUM BLADE ENCLOSURE FOR A LAWNMOWER
Text of the description
The present invention relates to a cutting blade enclosure and its manufacturing process, particularly the present invention relates to adoption of titanium as construction material of said blade enclosure.
The opportunity for making the most of the titanium mechanical and chemical strength characteristics in lawnmower manufacturing, and more specifically in manufacturing of lawnmower parts such as the frame which is the enclosure wherein the cutting blade are housed, up till now has not been taken into serious account by manufacturers from this technical field mainly due to the raw material high cost, which would make economically unprofitable use thereof for manufacturing structural parts of lawnmowers. Although it is not possible to direcdy act on the cost factor of the subject- matter material, it is possible to adopt manufacturing solutions that can justify the expense necessary for purchasing the raw material with technological advantages involving the whole service life of the so-manufactured lawnmower. Nevertheless it is to be noticed the progressive decrease of the raw material cost in the future potentially imputable to the change from the marketable titanium Kroll manufacturing process— from iron minerals and/ or igneous rocks - to the FFC-Cambridge manufacturing process which in respect of the previous process has a lower complexity and, therefore, a lower cost.
With the economic burden of adopting titanium as construction material for lawnmower blade enclosure, the dimensioning of the latter gains a huge benefit therefrom: in respect of a like steel blade enclosure, for example, a titanium blade enclosure has a mechanical strength, both in terms of ultimate strength and yield strength, slighdy lower but a whole weight lower than 40%, for which reason it is possible to adopt in the titanium
blade enclosure greater sections and, all things considered, a strength (or greater if desired) like the steel blade enclosure strength, by keeping a minor weight in respect thereof as well. Moreover, in respect of the aluminum on one hand titanium has a weight greater than about 60% but on the other hand it has an almost double strength: essentially by manufacturing the same blade enclosure with titanium, rather than with aluminum, it is possible to adopt thicknesses more than four times smaller, while keeping a noticeable strength, but decreasing the whole weight of the part also down to 50% in respect of the same manufactured with aluminum. In the following the main mechanical and thermal characteristics of the most used metallic materials in this technical field as well as of the titanium for a numerical comparison:
Carbon
Mechanical properties Stainless steel Aluminium Titanium steel
Density [gl crn \ 7.8 7.9 2.7 4.5
Ultimate strength [MP ] 458 610 320 475
Yeld strength [MPa] 305 480 210 390
Elongation [%] 30 54 12 20
Young's module [MPa] 21 Ό90 20 300 7 00 10 500
Thermal conductivity
65 90 236 19
[Wm 1 °C1]
A noticeable simplification of the manufacturing process, coming from the adoption of titanium in order to manufacture a lawnmower blade enclosure, is given from the absence of surface treatments after machining, since titanium is aesthetically nice to the sight— being polished by nature — but also to the touch due to its light superficial roughness. In addition, the surface treatments generally provided for the steel or aluminum blade enclosures for increasing their strength against the structural ageing, or chemical and mechanical etching of the weather are no more needed while adopting titanium, since it is naturally resistant to oxidation, due to the surface passivation just triggered by the oxidizer
acids, but also by sulphuric acid, hydrochloric acid, ammonia, alkali, brine, chloride solutions and the most of the carboxylic acids. Furthermore, thanks to a relatively high titanium melting point and a low coefficient of thermal expansion, a blade enclosure manufactured with such material keeps its mechanical characteristics intact even after a long exposure to the sun rays or, however, following up even high thermal ranges, which indeed almost slight distortions correspond to.
As each person skilled in the art could easily notice, the clear absence of surface treatments after machining for manufacture of the part causes the titanium blade enclosure to be wholly recyclable with a subsequent decrease of the environmental impact both during manufacture and disposal at the end of the lawnmower service life.
Finally, the titanium biocompatibility makes the lawnmower blade enclosure completely inert and, therefore, not contaminating thus allowing, in fact recommending, its use especially in areas subject to vegetable cultivations with food purposes and in play grounds.
Main object of the present invention is therefore to provide a lawnmower blade enclosure obtainable by a manufacturing process in which the used construction material is titanium.
A detailed description of the manufacturing process for obtaining titanium lawnmower blade enclosure according to the present invention with reference to the annexed drawings in which:
fig. 1 is a flow diagram showing steps of the manufacturing process of lawnmower titanium blade enclosure according to the present invention.
Referring now to fig. 1, step Fl provides the adoption of particular expedients in die design, that is, in respect of a like die for the manufacture of a stainless steel blade enclosure, it will necessary to use greater bending radii RTi since, for example, for a titanium
slab with a thickness of about 2 mm— reference size for this technical field— there is no opportunity to obtain bending radii smaller than about 2,5 mm.
In the step F2, as shown in fig. 1 , there is provided a cold drawing operation for the titanium slab: a choice of such machining is suggested by the high ductility offered by titanium— see the percent elongation in the previous mechanical characteristic table— on condition that the drawing pressure values within the press greater than in a like macliining of a steel blade enclosure. Again with reference to the step F2, it will be necessary to carefully adjust the combined action of the main press piston and the blank holder in order to recover, even partially, the drawing action loss which can reach even 20% to 30% of the bending radius.
The step F3, finally, already considered the high spring back of the titanium— see the Young's module in the previous mechanical characteristic table— leads to the complete dimensional recover of the die by means of welding operation or, alternatively, a riveting operation. Particularly, said welding operation, in order to obtain joints with the same mechanical and corrosion proofing characteristics of the rest of the die, is a MIG welding carried out according to the following expedients:
■ removal of impurities from joint edges with titanium or stainless steel brushes;
■ degreasing, for example, with acetone;
■ short-arc welding with torch tilt angle ranging from 45° to 90°;
■ shielding the welding bead with inert gas— for example Argon— even during cooling down to a temperature of about 200 °C;
■ at least doubling time for exposure to torch in respect of a like steel welding;
■ removal of the wire end— necessarily made of the same material— before starting the next welding.
It is clear from the just provided detailed description of the manufacturing process for lawnmower titanium blade enclosures according to the present invention that a lawnmower titanium blade enclosure can be obtained thus giving the lawnmower in the whole light characteristics, strength against corrosion, wear, (structural and aesthetic) ageing besides the complete biocompatibility of the product.
Claims
1. A lawnmower comprising a cutting means enclosure, wherein said cutting means enclosure is made by drawing titanium sheet and welding, inside the drawn frame, joints being able to made up for drawing action loss.
2. The lawnmower according to claim 1 , wherein said welding is a short-arc welding performed by:
(i) adopting a torch angle in a range between 45 and 90 degrees,
(ii) removing any impurity from each joint portion with a titanium or stainless steel brush,
(iii) degreasing said portion with acetone,
(iv) at least doubling the torch operation time in respect of steel,
(v) shielding the welding bead with inert gas while cooling down to a temperature below 200°C.
3. The lawnmower according to claim 2, wherein said welding is performed by also removing the welding wire end before going on with the next portion to be welded.
4. A lawnmower comprising a cutting means enclosure, wherein said cutting means enclosure is made by drawing titanium sheet and riveting, inside the drawn frame, joints being able to made up for drawing action loss.
5. The lawnmower according to claim 2 or 4, wherein said titanium sheet has a thickness of about 2 mm.
6. The lawnmower according to claim 5, wherein said drawing is performed by a die with no bend radius being smaller than 2 mm.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/IT2010/000145 WO2011125077A1 (en) | 2010-04-06 | 2010-04-06 | Titanium blade enclosure for a lawnmower |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| EP2555607A1 true EP2555607A1 (en) | 2013-02-13 |
Family
ID=43127617
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP10723353A Withdrawn EP2555607A1 (en) | 2010-04-06 | 2010-04-06 | Titanium blade enclosure for a lawnmower |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP2555607A1 (en) |
| WO (1) | WO2011125077A1 (en) |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4257214A (en) * | 1978-12-18 | 1981-03-24 | Duffers Associates, Inc. | Cross flow rotary mower |
| JPS5639107A (en) * | 1979-09-06 | 1981-04-14 | Nisshin Steel Co Ltd | Connecting method for titanium hot coil and stainless steel service tail |
| US4731981A (en) * | 1986-01-14 | 1988-03-22 | Tecumseh Products Company | Crankshaft impact protector |
| JP2002253027A (en) * | 2001-02-27 | 2002-09-10 | Honda Motor Co Ltd | Driving shaft structure of bush cutter |
| AU2008202668A1 (en) * | 2007-06-19 | 2009-01-15 | Fn Manufacturing, Llc. | Use of stainless steel rivets with titanium plating |
-
2010
- 2010-04-06 EP EP10723353A patent/EP2555607A1/en not_active Withdrawn
- 2010-04-06 WO PCT/IT2010/000145 patent/WO2011125077A1/en active Application Filing
Non-Patent Citations (1)
| Title |
|---|
| See references of WO2011125077A1 * |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2011125077A1 (en) | 2011-10-13 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107553066B (en) | A kind of forming method of metallic mobile phone shell | |
| JP5435914B2 (en) | Method for producing aluminum alloy plate for cold press forming, method for cold press forming aluminum alloy plate, and aluminum alloy cold press formed product | |
| JP2022062163A (en) | Titanium alloy | |
| CN102094220B (en) | Method for repairing titanium mother board | |
| CN103341520B (en) | A kind of TB9 square-section titanium alloy wire materials preparation technology | |
| CN105306632A (en) | Mobile phone shell and shell manufacturing process thereof | |
| TW201716596A (en) | Titanium material for hot rolling | |
| CN102230145A (en) | Method for producing TC25 two-phase titanium alloy rod material with large specification | |
| JP2019206757A (en) | Aluminum alloy suitable for high speed production of aluminum bottle, and process of manufacture thereof | |
| CN114161028B (en) | Processing method for improving performance of titanium alloy welding wire | |
| CN104190840A (en) | Die structure for hot upset forging of stainless steel bolt | |
| WO2015182748A1 (en) | Method for manufacturing aluminum alloy member and aluminum alloy member using same | |
| JP5973975B2 (en) | Titanium plate | |
| WO2011125077A1 (en) | Titanium blade enclosure for a lawnmower | |
| CN106498226B (en) | A kind of high beallon preparation method of photomultiplier dynode | |
| KR20200024262A (en) | Titanium | |
| EP2364377A1 (en) | Methods for the manufacture of a titanium alloy for use in combustion engine exhaust systems | |
| JP6128289B1 (en) | Titanium composite and titanium material for hot rolling | |
| JP5354136B1 (en) | Α + β Type Titanium Alloy Plate for Welded Pipe, Method for Producing the Same, and α + β Type Titanium Alloy Welded Pipe Product | |
| CN101812614A (en) | Method for preparing aero-engine casing | |
| TWI600772B (en) | Titanium composite material and hot processing titanium material | |
| US20210078457A1 (en) | Seat height adjustment device for a vehicle seat | |
| CN105929561A (en) | Ultralight alloy glasses frame and preparing technology thereof | |
| JP2002000971A (en) | Pure titanium/titanium alloy clad cutter and method for producing the same | |
| KR101536400B1 (en) | Welded ferritic stainless steel pipe joint having excellent corrosion resistance and method for manufacturing the same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
| 17P | Request for examination filed |
Effective date: 20121015 |
|
| AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK SM TR |
|
| DAX | Request for extension of the european patent (deleted) | ||
| GRAP | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOSNIGR1 |
|
| INTG | Intention to grant announced |
Effective date: 20140227 |
|
| STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
|
| 18D | Application deemed to be withdrawn |
Effective date: 20140710 |