GB2525641A - Handheld electric grinder with a brake device - Google Patents
Handheld electric grinder with a brake device Download PDFInfo
- Publication number
- GB2525641A GB2525641A GB1407652.5A GB201407652A GB2525641A GB 2525641 A GB2525641 A GB 2525641A GB 201407652 A GB201407652 A GB 201407652A GB 2525641 A GB2525641 A GB 2525641A
- Authority
- GB
- United Kingdom
- Prior art keywords
- brake
- shaft
- brake disc
- disc
- pad
- 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- Withdrawn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
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
- B24B23/00—Portable grinding machines, e.g. hand-guided; Accessories therefor
- B24B23/02—Portable grinding machines, e.g. hand-guided; Accessories therefor with rotating grinding tools; Accessories therefor
- B24B23/028—Angle tools
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
- B23Q11/00—Accessories fitted to machine tools for keeping tools or parts of the machine in good working condition or for cooling work; Safety devices specially combined with or arranged in, or specially adapted for use in connection with, machine tools
- B23Q11/0078—Safety devices protecting the operator, e.g. against accident or noise
- B23Q11/0092—Safety devices protecting the operator, e.g. against accident or noise actuating braking or stopping means
-
- 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
- B24B47/26—Accessories, e.g. stops
-
- 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
- B24B55/00—Safety devices for grinding or polishing machines; Accessories fitted to grinding or polishing machines for keeping tools or parts of the machine in good working condition
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
- Braking Arrangements (AREA)
Abstract
A handheld electric grinder includes a grinding body 20, a brake disc 40 fixed to a brake shaft portion 311 of a rotary shaft unit 30, a power switch (60 fig. 2) and a brake device 50 which includes a brake body 51, a brake coil 52, a plurality of brake springs 53 and a brake pad 54. When the power switch (60 fig. 2) is switched on, the rotary shaft unit 30 and the brake disc 40 rotate and the brake coil 52 produces a magnetic force to attract the brake pad 54, which moves away from the brake disc 40. When the power switch (60 fig. 2) is switched off, the rotary shaft unit 30 and the brake disc 40 decelerate, the brake coil 52 stops producing magnetic force, the second elastic end 532 of each of the brake springs 53 pushes the brake pad 54 toward the brake disc 40, so that the brake pad 54 is pressed against the brake disc 40 to produce brake effect. The brake disc 40 and brake unit 50 may be located on a motor shaft 31 or a wheel shaft 32 (fig. 6) of the rotary shaft unit. The grinder may be an angle grinder with bevel gears 312, 321.
Description
HANDHELD ELECTRIC GRINDER WITH A BRAKE DEVICE
BACKGROUND OF THE TNVENTTON
Field of the Invention
The present invention relates to a handheld electric grinder and, more particularly, to a handheld electric grinder with a brake device.
Description of the Prior Art
The existing handheld electric grinders are generally driven in a direct or indirect manner. As shown in Fig. 1, an indirect-drive handheld electric grinder is provided with a bevel gear 13 which is disposed between a motor shaft 11 and a wheel shaft 12 as a direction-change transmission medium. When a power switch 14 is switched on, the motor shaft 11 rotates and starts driving the wheel shaft 12 to rotate synchronously, so that a grinding wheel 15 mounted on the wheel shaft 12 can perform grinding.
When the power switch 14 is switched off, the motor shaft 11 loses power, however, it still takes some time for the motor shaft 11 to stop and, as a result, the motor shaft 11, the wheel shaft 12 and the grinding wheel 15 are unable to stop rotating within a short time. The user has to hold the grinder until it stops rotating, then he/she can put it away, which not only reduces grinding efficiency but also makes the grinding kind of dangerous. Besides, the handheld electric grinder is a low-speed high-torque electric tool and is very likely to vibrate and self-rotate if it is put away before it stops rotating, which makes the grinding work more dangerous.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.
SUMMARY OF THE INVENTION
The primary objective of the present invention is to provide a handheld electric grinder with a brake device, which is capable of improving grinding safety and efficiency.
To achieve the above objective, a handheld electric gfi!lder with a brake device in accordance with the present invention comprises: a grinding body; a rotary shaft unit pivoted to the grinding body and including a brake shaft portion; a brake disc fixed at the brake shaft portion and including a brake disc portion; the brake device provided for insertion of the brake shaft portion and including a brake body, a brake coil, a plurality of brake springs, and a brake pad, the brake body including a brake space for accommodation of the brake disc portion, the brake coil being fixed in the brake body and producing a magnetic force after being electrified, each of the brake springs including a first elastic end disposed in the brake body, and a second elastic end pushed against the brake disc, the brake pad being movably disposed in the brake space of the brake body in a manner that the brake pad is movable back and forth and located between the brake disc portion and the second elastic end; and a power switch being switchable between ON and OFF states, when the power switch is switched on, the rotary shaft unit and the brake disc will rotate, and the brake coil will produce a magnetic force to attract the brake pad, so that the brake pad moves away from the brake disc, when the power switch is switched off, the rotary shaft unit and the brake disc lose power and start to decelerate, the brake coil stops producing magnetic force, the second elastic end of each of the brake springs pushes the brake pad to move toward the brake disc, so that the brake pad is pressed against the brake disc to produce brake effect.
Preferably, the rotary shaft unit includes a motor shaft and a wheel shaft, the motor shaft is provided with tile brake shaft portion at one end, and a first bevel gear at another end thereof; at one end of the wheel shaft is fixed a second bevel gear for meshing with the first bevel gear, and at another end of the wheel shaft is provided a grinding wheel Preferably, the rotary shaft unit includes a motor shaft and a wheel shaft, the motor shaft has a free end, and at another end of the motor shaft is fixed a first bevel gear, at one end of the wheel shaft is fixed a second bevel gear for meshing with the first bevel gear, and at another end of the wheel shaft is provided a grinding wheel.
Preferably, the rotary shaft unit has one end formed with tile brake shaft portion and another end provided with the grinding wheel, so that the brake disc unit and the brake device are disposed n the rotary shaft unit.
Preferably, the brake body includes a plurality of cavities with an open end open toward the brake disc portion of the brake disc, and each of the brake springs has the first elastic end pressed against the bottom of a corresponding one of the cavities, and the first elastic end pressed against the brake pad.
BRIEF DESCRIPTION OF TIlE DRAWINGS
Fig. 1 is a side view of a conventional handheld electric grinder; Fig. 2 is an exploded view of a handheld electric grinder with a brake device in accordance with a first embodiment of the present invention; Fig. 3 is a side view of the handheld electric grinder with the brake device in accordance with the first embodiment of the present invention; Fig. 4 is a cross sectional view of a part of tile handheld electric grinder with the brake device in accordance with the first embodiment of the present invention, showing that the brake coil produces a magnetic force after being electrified; Fig. 5 is a cross sectional view of a part of the handheld electric grinder with the brake device in accordance with the first embodiment of the present invention, showing the status when the brake coil is powered off; Fig. 6 is a side view of a handheld electric grinder with a brake device in accordance with a second embodiment of the present invention; and Fig. 7 is a side view of a part of a handheld electric grinder with a brake device in accordance with a third embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will be clearer from the following description when viewed together with the accompanying drawings, which show, for purpose of illustration only, the preferred embodiments in accordance with the present invention.
Referring to Figs. 2-5, a handheld electric grinder with a brake device in accordance with a first embodiment of the present invention comprises: a grinding body 20, a rotary shaft unit 30, a brake disc 40, the brake device 50 and a power switch 60.
The grinding body 20 includes a head portion 21 and a body portion 22.
The rotary shaft unit 30 is pivoted to the grinding body 20 and includes a brake shaft portion 311. In this embodiment, the rotary shaft unit 30 includes a motor shaft 31 and a wheel shaft 32. The motor shaft 31 is provided with tile brake shaft portion 311 at one end, and a first bevel gear 312 at another end thereof. At one end of the wheel shaft 32 is fixed a second bevel gear 321 for meshing with the first bevel gear 312, and at another end of the wheel shaft 32 is provided a grinding wheel 322.
The brake disc 40 is fixed at the brake shaft portion 3 11 and includes a brake disc portion 41.
The brake device 50 is provided for insertion of the brake shaft portion 311 of the rotary shaft unit 30 and includes a brake body 51, a brake coil 52, a plurality of brake springs 53, and a brake pad 54.
The brake body 51 includes a brake space 511 for accommodation of the brake disc portion 41, and a plurality of cavities 512 with an open end 5121 open toward the brake disc portion 41 of the brake disc 40.
The brake coil 52 is fixed in the brake body 51 and produces a magnetic force after being electrified.
Each of the brake springs 53 has a first elastic end 531 disposed in the brake body 51, and a second elastic end 532 pushed against the brake disc 40. In this embodiment, each of the brake springs 53 is a compression spring with the first elastic end 531 pressed against the bottom 5122 of a conesponding one of the cavities 512.
The brake pad 54 is made of magnetically-attracted material and movably disposed in the brake space 511 of the brake body 51 in a manner of being movable back and forth. In this embodiment, the brake pad 54 is pushed toward the brake disc portion 41 of the brake disc 40 by the second elastic end 532.
The power switch 60 is switchable between ON and OFF states to make the brake pad 54 move away from or press against the brake disc portion 41 to produce a brake effect.
Referring to Fig. 4 again, when the power switch 60 is switched on, the rotary shaft unit 30 and the brake disc 40 will rotate, and the brake coil 52 will be electrified to produce a magnetic force to attract the brake pad 54 to move toward the brake coil 52, so that the brake pad 54 moves away from the brake disc 40 and compresses the brake springs 53, and at this moment, the handheld electric grinder is in a working state.
Referring then to Fig. 5, when the power switch 60 is switched off, the rotary shaft unit 30 will lose power and start to decelerate gradually, the brake coil 52 will stop producing magnetic force, making the brake pad 54 stop pressing against the brake springs 53. At this moment, the brake springs 53 are decompressed, and the second elastic end 532 pushes the brake pad 54 to move toward the brake disc 40, so that the brake pad 54 is pushed against the brake disc 40 to produce brake effect.
When the power switch 60 is switched from the "ON" state to "OFF" state, the brake springs 53 will be decompressed to make the brake pad 54 press against the brake disc portion 41 of the brake disc 40, so as to produce brake effect.
Therefore, the present invention is capable of reducing the time it takes for the rotary shaft unit 30 to completely stop rotating after losing power, so that the time the user has to hold tile eiectric grinder after it is powered off and, as a result, grinding efficiency and safety are both improved.
Referring then to Fig. 6, a handheld electric grinder with a brake device in accordance with a second embodiment of the present invention is similar to the first embodiment, except that: The rotary shaft unit 30A includes a motor shaft 3 1A and a wheel shaft 32A.
The motor shaft 3 IA has a free end, and at another end of the motor shaft 3 1A is fixed a first bevel gear 312A. At one end of the wheel shaft 32A is fixed a second bevel gear 321A for meshing with the first bevel gear 3 12A, and at another end of the wheel shaft 32A is provided a grinding wheel 322A. A brake shaft portion 323A is formed on the wheel shaft 32A, so that the brake disc unit 40A and the brake device 50A are disposed on the wheel shaft 32A.
Referring then to Fig. 7, a handheld electric grinder with a brake device in accordance with a third embodiment of the present invention is similar to the first embodiment, except that: The rotary shaft unit 30B is a single unitary shaft which has one end formed with the brake shaft portion 301B and another end provided with a grinding wheel 302B, so that the brake disc unit 40B and the brake device 50B are disposed on the rotary shaft unit 30B.
Claims (6)
- WHAT IS CLAIMED IS: 1. A handheld electric grinder with a brake device comprising: a grinding body; a rotwy shaft unit pivoted to the grinding body and including a brake shaft portion; a brake disc fixed at the brake shaft portion and including a brake disc portion; the brake device provided for insertion of the brake shaft portion and including a brake body, a brake coil, a plurality of brake springs, and a brake pad, the brake body including a brake space for accommodation of the brake disc portion, the brake coil being fixed in the brake body and producing a magnetic force after being electrified, each of the brake springs including a first elastic end disposed in the brake body, and a second elastic end pushed against the brake disc, the brake pad being movably disposed in the brake space of the brake body in a manner that the brake pad is movable back and forth and located between the brake disc portion and the second elastic end; and a power switch being switchable between ON and OFF states, when the power switch is switched on, the rotary shaft unit and the brake disc will rotate, and the brake coil will produce a magnetic force to attract the brake pad, so that the brake pad moves away from the brake disc, when the power switch is switched off, the rotary shaft unit and the brake disc lose power and start to decelerate, the brake coil stops producing magnetic force, the second elastic end of each of the brake springs pushes the brake pad to move toward the brake disc, so that the brake pad isSpressed against the brake disc to produce brake effect.
- 2. The handheld electric grinder with the brake device as claimed in claim 1, wherein tile rotary shaft unit inciudes a motor shaft and a wheel shaft, the motor shaft is provided with the brake shaft portion at one end, and a first bevel gear at another end thereof at one end of the wheel shaft is fixed a second bevel gear for meshing with the first bevel gear, and at another end of the wheel shaft is provided a grinding wheel
- 3. The handheld electric grinder with the brake device as claimed in claim 1, wherein the rotary shaft unit includes a motor shaft and a wheel shaft, the motor shaft has a free end, and at another end of the motor shaft is fixed a first bevel gear, at one end of the wheei shaft is fixed a second bevel gear for meshing with the first bevel gear, and at another end of the wheel shaft is provided a grinding wheel.
- 4. The handheld electric grinder with the brake device as claimed in claim I, wherein the rotary shaft unit has one end formed with the brake shaft portion and another end provided with the grinding wheel, so that the brake disc unit and the brake device are disposed on the rotary shaft unit.
- 5. The handheld electric grinder with the brake device as claimed in claim 1, wherein the brake body includes a plurality of cavities with an open end open toward the brake disc portion of the brake disc, and each of the brake springs has the first elastic end pressed against the bottom of a corresponding one of the cavities, and the first elastic end pressed against the brake pad.
- 6. A handheld electric grinder substantially as hereinbefore described with reference to and as shown in Figures 2 to 7 of the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1407652.5A GB2525641A (en) | 2014-05-01 | 2014-05-01 | Handheld electric grinder with a brake device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1407652.5A GB2525641A (en) | 2014-05-01 | 2014-05-01 | Handheld electric grinder with a brake device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB201407652D0 GB201407652D0 (en) | 2014-06-18 |
| GB2525641A true GB2525641A (en) | 2015-11-04 |
Family
ID=50980396
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB1407652.5A Withdrawn GB2525641A (en) | 2014-05-01 | 2014-05-01 | Handheld electric grinder with a brake device |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2525641A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106827026A (en) * | 2017-04-11 | 2017-06-13 | 广州元凛建筑工程技术开发有限公司 | A kind of plate cutting device |
| CN112276742A (en) * | 2020-10-29 | 2021-01-29 | 义乌郝天贸易有限公司 | Building materials burr abrasive band of polishing is with preventing device that skids |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2580126A1 (en) * | 1985-04-04 | 1986-10-10 | Fein C & E | Hand-held electric tool e.g. saw, plane or polisher |
| DE3741536A1 (en) * | 1987-12-08 | 1989-06-22 | Erhard Pauls | Brake device for braking rotating machine elements, such as the rotor of a manual angle grinder |
| DE19604712A1 (en) * | 1996-02-09 | 1997-08-14 | Abb Patent Gmbh | Electromechanical friction brake especially for angle-grinding machine |
-
2014
- 2014-05-01 GB GB1407652.5A patent/GB2525641A/en not_active Withdrawn
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2580126A1 (en) * | 1985-04-04 | 1986-10-10 | Fein C & E | Hand-held electric tool e.g. saw, plane or polisher |
| DE3741536A1 (en) * | 1987-12-08 | 1989-06-22 | Erhard Pauls | Brake device for braking rotating machine elements, such as the rotor of a manual angle grinder |
| DE19604712A1 (en) * | 1996-02-09 | 1997-08-14 | Abb Patent Gmbh | Electromechanical friction brake especially for angle-grinding machine |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106827026A (en) * | 2017-04-11 | 2017-06-13 | 广州元凛建筑工程技术开发有限公司 | A kind of plate cutting device |
| CN112276742A (en) * | 2020-10-29 | 2021-01-29 | 义乌郝天贸易有限公司 | Building materials burr abrasive band of polishing is with preventing device that skids |
Also Published As
| Publication number | Publication date |
|---|---|
| GB201407652D0 (en) | 2014-06-18 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |