EP0727278A1 - Improved wet grinder - Google Patents
Improved wet grinder Download PDFInfo
- Publication number
- EP0727278A1 EP0727278A1 EP96100896A EP96100896A EP0727278A1 EP 0727278 A1 EP0727278 A1 EP 0727278A1 EP 96100896 A EP96100896 A EP 96100896A EP 96100896 A EP96100896 A EP 96100896A EP 0727278 A1 EP0727278 A1 EP 0727278A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- transmission
- wet grinder
- grinding wheel
- grinder according
- pulley
- 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- Withdrawn
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B47/00—Drives or gearings; Equipment therefor
- B24B47/10—Drives or gearings; Equipment therefor for rotating or reciprocating working-spindles carrying grinding wheels or workpieces
- B24B47/12—Drives or gearings; Equipment therefor for rotating or reciprocating working-spindles carrying grinding wheels or workpieces by mechanical gearing or electric power
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B3/00—Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools
- B24B3/36—Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools of cutting blades
- B24B3/52—Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools of cutting blades of shear blades or scissors
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B3/00—Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools
- B24B3/36—Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools of cutting blades
- B24B3/54—Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools of cutting blades of hand or table knives
Definitions
- the present invention relates to an improved wet grinder, particularly for home and workshop use.
- Conventional wet grinders that are currently commercially available are generally formed by a supporting structure made of substantially rigid material that internally accommodates a cylindrical grinding wheel that partially protrudes outside and is connected to an electric motor through a mechanical transmission.
- the transmissions used for these grinders are usually constituted by straight-tooth gears, helical gears, or worm gears. Accordingly, if one wishes to achieve an acceptable efficiency and a limited noise, it is necessary to provide rather tight tolerances when assemblying the gears. It may also be necessary to use expensive bushes, which must be constantly lubricated even in the vicinity of wet regions, such as the water tray of the grinder. If the supports wear, or if there are machining errors, the efficiency of these transmissions can drop considerably and the noise consequently increases. Finally, conventional grinders have a relatively high cost with respect to the performance and the efficiency that they deliver.
- the smooth surfaces for contact between the pulleys and the belts are subject to slippages and do not allow to transmit considerable torques. To avoid such slippages it is therefore necessary to apply tension to the belts, which unavoidably causes a reduction in the efficiency of the transmission and higher wear on the supports of the shafts. Furthermore, higher-power motors must be used.
- the aim of the present invention is to eliminate the drawbacks described above by providing an improved wet grinder that is more economical than prior ones for equal performance and efficiency.
- a particular object is to achieve maximum simplification of the machining and assembly operations.
- Another object is to provide a wet grinder having normal performance by using motors of limited power.
- Another object is to provide a wet grinder that is extremely quiet, safe, clean, and very easy to maintain.
- a wet grinder of the type defined in the introduction characterized in that the mechanical transmission includes at least one elastic toothed belt.
- the belt can be made of uniform thermoplastic elastomeric material without a core of inextensible material.
- the teeth of the belts allow optimum slip-free torque transmission, increasing the efficiency of the transmission itself, allowing the use of less powerful motors and no longer requiring the use of bushes and bearings on the pulley shafts.
- the elasticity of the belt causes the operation of the grinder to be very silent and pleasant for the user, making it particularly suitable for use in a small environment, such as the home and the workshop.
- the wet grinder according to the invention includes a supporting structure formed by a lower casing, or shell, 2 that is obtained by molding or injection of thermoplastic materials.
- Shell 2 has side and bottom walls, having an approximately prism-like shape, and lower resting feet 3.
- the shell has longitudinal and transverse vertical dividing walls that form, inside the shell, four compartments 4, 5, 6, and 7 that are mutually independent and isolated.
- Compartment 4 accommodates an electric motor 8 connected to a switch 10 by electric terminals 9.
- the switch is inserted in the watertight compartment 5 and can be connected to an external power outlet by a power supply cable 11.
- compartment, or tray 6, with a hermetic bottom for collecting cooling water, contains a cylindrical grinding wheel 12, whereas compartment 7 accommodates a transmission, generally designated by the reference numeral 13.
- slots 14 and 15 are provided on the bottom of compartments 4 and 7 for the forced ventilation of motor 8, which is achieved by a fan 16, keyed on its shaft.
- transmission 13 includes at least one toothed and elastic transmission belt.
- the transmission is of the two-stage type.
- a first stage is constituted by a first toothed pulley 17, made for example of molded or injected plastic, which is keyed on the shaft of the motor 8.
- a second stage has a second pulley 18, which is also toothed and made of the same material and has a larger diameter than the first one.
- Second pulley 18 is rigidly coupled to a hollow shaft 19 mounted on a pivot 20. Pivot 20 is accommodated in seats 21 formed in the shell 2, as clearly shown in Figure 5.
- the ratio between the diameters of pulleys 17 and 18, and therefore the transmission ratio of the pair can be between 1:3 and 1:4.
- the two pulleys are connected by a toothed belt 22 that has the same modulus, which can be for example 3 mm.
- Belt 22 can be made of elastomeric material, such as natural or synthetic rubber, with no internal core so that it can elongate elastically, by virtue of molding or injection processes.
- the second stage of the transmission is constituted by a second reduction pair formed by a third toothed pulley 23, which is coaxial and rigidly coupled to the shaft 19 of the first pulley 17, and by a fourth toothed pulley 24 that is keyed to the shaft 25 of grinding wheel 12; the same remarks made for the first pair of pulleys 17 and 18 apply to this second pair.
- pulleys 23 and 24 are connected by a toothed elastic belt 26 that is similar to the preceding one.
- Shaft 25 of the grinding wheel is also hollow and is supported by a pivot 27 that is accommodated in seats 28 formed in shell 2.
- Shell 2 can be closed by an upper lid 29 that can be screwed or snapped on, ensuring the tightness of compartment 5 for electric switch 10 and an open compartment for grinding wheel 12.
- pivots 20 and 27 can be made of steel
- the pulleys and their shafts are made of antifriction, self-lubricating plastic to reduce friction, so as to avoid any action for lubrication and maintenance.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Preparation Of Clay, And Manufacture Of Mixtures Containing Clay Or Cement (AREA)
- Lasers (AREA)
- Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
Abstract
A wet grinder includes a supporting shell made of a substantially rigid material that internally accommodates a cylindrical grinding wheel (12) that protrudes partially outside and is connected to an electric motor (8) by a mechanical transmission (13) that includes at least one elastic toothed belt (22, 26). The belt is made of thermoplastic uniform elastomeric material without a core of inextensible material. The transmission is of the two-stage type, in which each stage is constituted by a pair of toothed pulleys that are mutually coupled by an elastic toothed belt (22, 26). The shafts of the pulleys are made of antifriction, self-lubricating plastics and are supported by respective pivots (20, 27) that are inserted in seats (21, 28) of the supporting shell (2) without interposing bushes or bearings. The grinder is very cheap and silent, and the elastic toothed belts allow to compensate for considerable variations in plays and for wide center distance tolerances.
Description
- The present invention relates to an improved wet grinder, particularly for home and workshop use.
- Conventional wet grinders that are currently commercially available are generally formed by a supporting structure made of substantially rigid material that internally accommodates a cylindrical grinding wheel that partially protrudes outside and is connected to an electric motor through a mechanical transmission.
- The transmissions used for these grinders are usually constituted by straight-tooth gears, helical gears, or worm gears. Accordingly, if one wishes to achieve an acceptable efficiency and a limited noise, it is necessary to provide rather tight tolerances when assemblying the gears. It may also be necessary to use expensive bushes, which must be constantly lubricated even in the vicinity of wet regions, such as the water tray of the grinder. If the supports wear, or if there are machining errors, the efficiency of these transmissions can drop considerably and the noise consequently increases. Finally, conventional grinders have a relatively high cost with respect to the performance and the efficiency that they deliver.
- In order to reduce the noise, transmissions with smooth belts, having a trapezoidal cross-section and a core that is reinforced with nylon fibers or the like, have also been used. However, these belts are incapable of stretching and do not allow to change the distance between the axes of the gears, which therefore must have tight tolerances.
- Furthermore, the smooth surfaces for contact between the pulleys and the belts are subject to slippages and do not allow to transmit considerable torques. To avoid such slippages it is therefore necessary to apply tension to the belts, which unavoidably causes a reduction in the efficiency of the transmission and higher wear on the supports of the shafts. Furthermore, higher-power motors must be used.
- The aim of the present invention is to eliminate the drawbacks described above by providing an improved wet grinder that is more economical than prior ones for equal performance and efficiency.
- Within the scope of this aim, a particular object is to achieve maximum simplification of the machining and assembly operations.
- Another object is to provide a wet grinder having normal performance by using motors of limited power.
- Another object is to provide a wet grinder that is extremely quiet, safe, clean, and very easy to maintain.
- This aim, these objects, and others which will become apparent hereinafter are achieved by a wet grinder of the type defined in the introduction, characterized in that the mechanical transmission includes at least one elastic toothed belt.
- The belt can be made of uniform thermoplastic elastomeric material without a core of inextensible material.
- In this manner, the tolerances between the center distances can be increased, since they are easily compensated by the elasticity of the belts. This entails a considerable saving in the operations for machining the supports of the pulleys and simplification of the assembly operations.
- Furthermore, the teeth of the belts allow optimum slip-free torque transmission, increasing the efficiency of the transmission itself, allowing the use of less powerful motors and no longer requiring the use of bushes and bearings on the pulley shafts.
- Furthermore, the elasticity of the belt causes the operation of the grinder to be very silent and pleasant for the user, making it particularly suitable for use in a small environment, such as the home and the workshop.
- The substantially complete use of plastic materials for the various components makes lubrication superfluous and therefore reduces maintenance costs.
- Further characteristics and advantages will become apparent from the detailed description of a preferred but not exclusive embodiment of a wet grinder according to the invention, illustrated only by way of non-limitative example in the accompanying drawings, wherein:
- Figure 1 is a general perspective front elevation view of the grinder according to the invention;
- Figure 2 is a perspective rear elevation view of the grinder of Figure 1, with the lid removed to show its internal structure;
- Figure 3 is a side view of the grinder of Figures 1 and 2;
- Figure 4 is a plan view of the grinder of the preceding figures;
- Figure 5 is an exploded perspective view of the grinder according to the invention.
- With reference to the above figures, the wet grinder according to the invention, generally designated by the
reference numeral 1, includes a supporting structure formed by a lower casing, or shell, 2 that is obtained by molding or injection of thermoplastic materials. Shell 2 has side and bottom walls, having an approximately prism-like shape, and lower restingfeet 3. - The shell has longitudinal and transverse vertical dividing walls that form, inside the shell, four
compartments -
Compartment 4 accommodates anelectric motor 8 connected to aswitch 10 byelectric terminals 9. The switch is inserted in thewatertight compartment 5 and can be connected to an external power outlet by apower supply cable 11. - The compartment, or
tray 6, with a hermetic bottom for collecting cooling water, contains acylindrical grinding wheel 12, whereascompartment 7 accommodates a transmission, generally designated by the reference numeral 13. - Advantageously,
slots compartments motor 8, which is achieved by afan 16, keyed on its shaft. - According to the invention, transmission 13 includes at least one toothed and elastic transmission belt.
- In particular, the transmission is of the two-stage type. A first stage is constituted by a first
toothed pulley 17, made for example of molded or injected plastic, which is keyed on the shaft of themotor 8. A second stage has asecond pulley 18, which is also toothed and made of the same material and has a larger diameter than the first one.Second pulley 18 is rigidly coupled to ahollow shaft 19 mounted on apivot 20.Pivot 20 is accommodated inseats 21 formed in theshell 2, as clearly shown in Figure 5. - Merely by way of example, the ratio between the diameters of
pulleys - The two pulleys are connected by a
toothed belt 22 that has the same modulus, which can be for example 3 mm.Belt 22 can be made of elastomeric material, such as natural or synthetic rubber, with no internal core so that it can elongate elastically, by virtue of molding or injection processes. - The second stage of the transmission is constituted by a second reduction pair formed by a third
toothed pulley 23, which is coaxial and rigidly coupled to theshaft 19 of thefirst pulley 17, and by a fourthtoothed pulley 24 that is keyed to theshaft 25 of grindingwheel 12; the same remarks made for the first pair ofpulleys - In this case, too,
pulleys elastic belt 26 that is similar to the preceding one. -
Shaft 25 of the grinding wheel is also hollow and is supported by apivot 27 that is accommodated inseats 28 formed inshell 2. - By means of
belts seats pivots -
Shell 2 can be closed by anupper lid 29 that can be screwed or snapped on, ensuring the tightness ofcompartment 5 forelectric switch 10 and an open compartment for grindingwheel 12. - Whereas
pivots - The wet grinder according to the invention is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept expressed by the claims that follow.
- All the details may be replaced with technical equivalents, all of which are understood to be equally protected; the dimensions and the materials may be any according to the requirements, so long as they achieve the same final effect.
Claims (9)
- Wet grinder, comprising a supporting shell made of a substantially rigid material that internally accommodates a cylindrical grinding wheel (12) that protrudes partially outside, and an electric motor (8) that is connected to said grinding wheel by a mechanical transmission (13), characterized in that said mechanical transmission (13) comprises at least one elastic toothed belt (22, 26).
- Wet grinder according to claim 1, characterized in that said elastic toothed belt (22, 26) is made of thermoplastic uniform elastomeric material without a core of inextensible material, so as to compensate considerable variations in plays and wide tolerances in center distances.
- Wet grinder according to claim 1, characterized in that said transmission is of the two-stage type, each stage being constituted by a pair of toothed pulleys that are mutually coupled by an elastic toothed belt (22, 26).
- Wet grinder according to claim 3, characterized in that the first pulley (17) of the first transmission pair is mounted on the shaft of the motor (8) and the second pulley (18) of the second transmission pair is keyed on the shaft (25) of the grinding wheel (12).
- Wet grinder according to claim 4, characterized in that the second pulley (18) of the first transmission pair and the first pulley (23) of the second transmission pair are formed monolithically on an intermediate free shaft (19).
- Wet grinder according to claim 5, characterized in that both said intermediate free shaft (19) and said grinding wheel-supporting shaft (25) are made of antifriction and self-lubricating plastic material and are supported by respective pivots (20, 27) that are inserted in seats (21, 28) of said supporting shell (2) without the interposition of bushes or bearings.
- Wet grinder according to claim 1, characterized in that said shell (2) has side and bottom walls that have an approximately prismatic shape and is internally provided with longitudinal and transverse walls that are suitable to form separate compartments (4, 5, 6, 7) respectively for said motor (8), for said switch (10), for said grinding wheel (12), and for said transmission (13).
- Wet grinder according to claim 7, characterized in that said supporting structure comprises an upper lid (29) that can be detachably coupled to said lower shell (2) and is suitable to completely close said compartment (4) for the motor, said compartment (5) for the switch (10), and said compartment (7) for the transmission (13), and to leave said compartment (6) for the grinding wheel (12) uncovered.
- Wet grinder according to claim 8, characterized in that some of said compartments (4, 7) have, on their bottom, ventilation slots (14, 15) for the motor.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
ITVI950016 IT239376Y1 (en) | 1995-02-20 | 1995-02-20 | IMPROVED WATER WHEEL |
ITVI950016 | 1995-02-20 |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0727278A1 true EP0727278A1 (en) | 1996-08-21 |
Family
ID=11425663
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP96100896A Withdrawn EP0727278A1 (en) | 1995-02-20 | 1996-01-23 | Improved wet grinder |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP0727278A1 (en) |
IT (1) | IT239376Y1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN105935913A (en) * | 2016-06-28 | 2016-09-14 | 苏州博来喜电器有限公司 | Vertical sander for reducing wear |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2310835A1 (en) * | 1975-05-10 | 1976-12-10 | Streicher Emide Metall | Motor driven knife sharpener with enclosure - having inclined guide slots and at least part of enclosure removable |
DE7727096U1 (en) * | 1977-09-01 | 1977-12-08 | Friedr. Dick Gmbh, 7300 Esslingen | GRINDING DEVICE FOR SHARPENING KNIFE CUTTERS |
GB2046145A (en) * | 1979-04-14 | 1980-11-12 | Hanning Elektro Werke | Machine for Sharpening Cutting Tools or Grinding Other Materials |
EP0591109A1 (en) * | 1992-09-01 | 1994-04-06 | Patrizio Fazzini | Improved apparatus for grinding and sharpening blades in general |
DE9315019U1 (en) * | 1993-10-04 | 1995-02-02 | Bosch Gmbh Robert | Eccentric disc grinder |
-
1995
- 1995-02-20 IT ITVI950016 patent/IT239376Y1/en active
-
1996
- 1996-01-23 EP EP96100896A patent/EP0727278A1/en not_active Withdrawn
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2310835A1 (en) * | 1975-05-10 | 1976-12-10 | Streicher Emide Metall | Motor driven knife sharpener with enclosure - having inclined guide slots and at least part of enclosure removable |
DE7727096U1 (en) * | 1977-09-01 | 1977-12-08 | Friedr. Dick Gmbh, 7300 Esslingen | GRINDING DEVICE FOR SHARPENING KNIFE CUTTERS |
GB2046145A (en) * | 1979-04-14 | 1980-11-12 | Hanning Elektro Werke | Machine for Sharpening Cutting Tools or Grinding Other Materials |
EP0591109A1 (en) * | 1992-09-01 | 1994-04-06 | Patrizio Fazzini | Improved apparatus for grinding and sharpening blades in general |
DE9315019U1 (en) * | 1993-10-04 | 1995-02-02 | Bosch Gmbh Robert | Eccentric disc grinder |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN105935913A (en) * | 2016-06-28 | 2016-09-14 | 苏州博来喜电器有限公司 | Vertical sander for reducing wear |
Also Published As
Publication number | Publication date |
---|---|
ITVI950016U1 (en) | 1996-08-20 |
ITVI950016V0 (en) | 1995-02-20 |
IT239376Y1 (en) | 2001-02-26 |
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Legal Events
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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 |
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AK | Designated contracting states |
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17P | Request for examination filed |
Effective date: 19970220 |
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17Q | First examination report despatched |
Effective date: 19970902 |
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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 |
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18D | Application deemed to be withdrawn |
Effective date: 19980313 |