JP2682995B2 - Handheld machine tools, especially protective hoods for polishing machines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a protective hood for a hand-held machine tool, in particular a grinding machine, wherein the protective hood is attached to the hand-held machine tool by a tightening screw that tightens a tightening band on the protective hood side. The present invention relates to a type that is tightly tightened to a tightening neck. In the known protective hood, the tightening screw consists of a screw having a slit or a hexagonal hole in the screw head, which screw is threaded through one tightening band ear and on the other tightening band ear, For example, it can be screwed into a nut welded to the fastening band ear. To tighten or loosen the tightening band,
You will need a tool that fits the head of the tightening screw, such as a screwdriver or a hex driver. Such tools must be carried separately. Tightening the slotted screw with an oversized blade screwdriver will damage the slit. In addition, an excessively small screwdriver cannot provide the tightening force necessary to securely and securely tighten the protective hood. As a result, the protective hood may sag, which creates a dangerous condition for machine tool users.
Further, in the case of a screw having a hexagonal hole in the screw head, the same result will occur even if dust is clogged in the hexagonal hole, that is, the hexagon head screw driver cannot be properly installed in the hexagonal hole.
On the other hand, the protective hood according to the invention for hand-held machine tools, in particular for grinding machines, which has the features of claims 1 and 11 has the following advantages. That is, the protective hood of the present invention can be tightened and loosened or removed without the use of additional auxiliary tools. The structures of the protective hood and the tightening band itself are the same as those conventionally known. The lever, which is permanently attached to the tightening band, transmits a sufficient torque by rotating the tightening screw, which ensures a secure and safe tightening of the protective hood. It is easy to handle and has a quick detaching function.
The tightening screw ensures a reliable tightening of the protective hood even if the diameter of the tightening neck on the machine tool side is large. The construction of the protective hood according to the invention is simple. The protective hood has only a few components and can therefore be manufactured easily and inexpensively as a whole. As a further advantage, a constant holding force is obtained in the tightened position in which the lever is swiveled inward, which holding force is independent of the respective torque magnitude for the tightening screw. The protective hood also serves as a very robust adapter and is immune to external forces and dirt. The measures as claimed in claims 2 to 10 represent advantageous embodiments of the protective hood as claimed in claim 1. The measures as claimed in claims 12 to 23 represent an advantageous embodiment of the protective hood as claimed in claim 11. Such an eccentric disc type clamping device can be operated quickly and easily without the need for any tools. The invention will now be described with reference to the illustrated embodiment. 1 to 4 show a first embodiment of a protective hood 10 suitable for hand-held machine tools, in particular for grinding machines. In this case, the polishing plate is especially an L-shaped polishing plate. This grinding machine has a fixed receiving portion screwed to the drive shaft of the grinding wheel, and the fixing receiving portion supports a cylindrical tightening neck portion on the flange. A drive shaft extends through the center of the cylindrical clamping neck and the clamping neck has at least a substantially smooth outer peripheral surface. The clamping neck is, for example, a cast part. Protective hood on this tightened neck 10
Is exchangeably fixed. For this fastening, a fastening band 11 consisting of a sheet metal, which is immovably connected to the protective hood 10, serves, for example, over a peripheral angle range of approximately 320 ° and both fastening band sections 12. , 13 have bent ears 14, 15 at the ends thereof, which ears 14, 15 extend at least approximately parallel to each other, in order to immobilize the protective hood 10 on the clamping neck. , Are fastened to each other by tightening screws 16. The protective hood 10 has a clamping device 17 which acts in engagement with a clamping screw 16 and which enables tool-less clamping.
This device acts on the flat-fabricated end 18 of the clamping screw 16 and has a lever 19, which in this case consists of spring steel wire and is bent into two substantially hairpin-shaped legs.
20 and 21, which are of different lengths and which are bent at substantially right angles with leg ends 22 and 23 which are associated with respective holes 24 of the flat end 18 of the clamping screw 16. It is inserted into 25 and is pivotally mounted in the bore about each axis, each axis being at right angles to the longitudinal direction of the clamping screw 16. The lever 19 extends substantially along the arc shape of the lower tightening band section 13 in FIG. 1 and is manufactured in a substantially similar arc shape. The lever 19 extends approximately within this tightening band section 13, as shown in FIG.
At the end opposite the leg ends 22, 23, the lever 19 has a free gripping end 26 extending from the arcuate section.
As shown in FIG. 1, the lever 19 is located on the side opposite to the side of the tightening band 12 on which the cover hood is immovably supported. The lever 19 is itself held in the tightened position shown in FIG. 1, in which position the lever 19 is
19 is swung to the side of the adjacent tightening band section 13. This position is caused in this case by spring elasticity and by the fact that both legs 20, 21 are made of spring steel wire. Both legs 20 and 21 are bent in a direction in which they approach each other before assembly, and as a result, in the assembled state shown in FIGS. Held within 25. Hole 24 and hole 25 are, in another embodiment, a tightening screw 16
It may be arranged along the central axis of (not shown). On the other hand, in the illustrated embodiment, the holes 24, 25 are arranged on a connecting line extending obliquely to the central axis of the screw 16 (FIG. 1). That is, the holes 24 and 25 are located apart from each other on the connecting line with a distance a. The shorter leg 21 is sufficiently displaced with respect to the longer leg 20 in the unassembled condition so that the leg end 23 of the shorter leg 21 has a hole 25.
This shorter leg 21 provides a spring-elastic preload on the lever 19 when inserted therein. Due to the distance "a" and the "deviation" described above, the legs 20 and 21 are deflected at the tightening position when the lever 19 is swung to the position shown in FIG. Press on 13 and hold in this position. By appropriately matching the distance “a” and the above “deviation”, the lever at the position turned outward
It is possible to exert a smaller restoring force on 19 than in the inwardly swung clamping position shown in FIG. The clamping screw 16 is screwed into the internal thread part 28 by means of a thread section 27, which in this case consists of a nut which is connected to the ear 14 for example by welding. The clamping screw 16 is supported on the other ear 15 by means of its axial abutment surface 29, which abutment surface 30 is integral with the clamping screw 16.
It is provided in. Flat end 18 to which the lever 19 is connected
Continues to this axial contact surface. Lever in this configuration
19 is configured as a crank for rotating the tightening screw 16. The thread division 27 and the female thread portion 28 belonging to it are the threads of a small pitch, for example a thread of pitch 0.75.
It has an M8. To immobilize the protective hood 10 on the clamping neck of the hand-held machine tool, the lever 19 is swiveled from the clamping position shown in FIG. 1 to the releasing position shown in FIG. For tightening, tighten the tightening screw 16 by turning the lever 19. The lever 19 is narrow, however, for example almost positive
It can be swung back again within a rotation angle range of -10 °. This is the most inconvenient case, if the clamping bolt 16 is tightened and the lever 19 is now beyond the return range and is also in the angular position of, for example, 160 °.
There are two possible means for moving the lever 19 into the pivoted clamping position. That is, the lever 19 is rotated in the opposite direction by 160 ° and returned, or is further rotated by 160 °.
Due to the small thread pitch and the spring-elastic flexibility of the tightening band 11, the tightening band is the first possible means.
11 produces very little tightening tension. In the second possible way, a very high torque must additionally be applied to the lever 19, which acts as a crank. The clamp device 17 according to the first embodiment has the following advantages. That is, the lever 19 that is permanently attached to the protective hood 10 allows the use of a large force without
A sufficient torque required for tightening each time can be applied. As a result, the protective hood 10 can be securely and safely tightened. No special tools are required for this. Easy to handle. Even if there is a deviation in the diameter of the tightening neck on the machine tool side, reliable and secure tightening of the protective hood 10 is guaranteed. Furthermore, the structure of the protective hood 10 is simple. The protective hood 10 has very few components and can be manufactured inexpensively as a whole. At the tightening position where the lever is swung to the tightening band side, a constant and constant tightening force is guaranteed. This constant and constant tightening force is independent of the torque applied to the tightening screw 16. Also, there are no wear parts that reduce the protective hood clamping force. The clamping device 17 can also be used semi-permanently as a very robust adapter. It is also immune to external influences, especially dust or other contaminants. In the second embodiment shown in FIGS. 5 and 6, parts corresponding to those in the first embodiment are given a reference numeral plus 100 in order to avoid duplication with the description of the first embodiment. Has been done. In the second embodiment, the protective hood 10 has the same structure. But lever 119 is a single rod lever 1 in this case
It is manufactured as 31. Tightening screw 116 is 30 in the axial direction.
It has a forked hawk 132, followed by a hawk leg of this hawk 1
A bearing part 135 is inserted between 33 and 134, which part is provided at the end of the lever 119. Both bearing hawk legs 13
A bearing pin 136 extends at a right angle through 3,134 and the bearing part 135, whereby the lever 119 is held by a tightening screw 116 so as to be pivotable about the axis of the bearing pin 136. Also in this second embodiment, the lever 119 is spring-elastically held in the inwardly swung clamping position shown in FIG. This spring-elastic holding state is caused by the outer spring 137 configured as a torsion spring 138. This spring is a pin 1 immovably mounted on the protective hood 110.
Protective hood 110 held at 39 with one spring end 140
It is supported by. The other spring end 141 engages a lever 119, which spring-elastically presses it into the clamping position shown in FIG. This free spring end 14
1 has a bent hook 142, which is bent at a substantially right angle as shown in FIG. 6 to the right in FIG. 6 and is applied to the outer back of the lever 119. It extends at a right angle to. The hook 142 is further followed from this by an end leg 143 which is bent at a substantially right angle, which leg is also oriented at a right angle to the direction of extension of the lever 119, on one side of the lever 119. Around. The spring 137 presses the lever 119 with the hook 142. End leg 1
43 in this case engages around the lever 119, which causes the spring end 141 to be displaced when the lever 119 is moved to the outward pivoted position shown in phantom in FIG.
Some slippage is prevented. The lever 119, like the lever 19 of FIG. 1, has a free end 126 for the handle that is easy to grip. Also in the third embodiment shown in FIGS. 7 and 8, the lever 21
The 9 is constructed as a single lever, which can be, for example, a sheet metal molded part. The clamping device is configured as an eccentric disc type clamping device 244 in this embodiment. The lever 219 has end-side clamping surfaces 246, 247 eccentrically extending with respect to its pivot axis 245, these clamping surfaces being indirect to the ears 215 of one clamping band section 213. Is in contact with. The lever 219 has a bifurcated fork 248 in the region of this end, on both of which fork legs 249, 250 a bearing pin 251 passes with play of movement, so that the lever 219 thus bears. It is rotatably supported by. The bearing pin 251 extends at right angles to the clamping screw 216. The bearing pin has an internal threaded hole 252 into which a thread section 253 at the end of the clamping screw 216 is adjustably screwed. If the threads of the latter thread section 253 are caulked, for example, this makes it possible to prevent slipping out. The tightening screw 216 has an axial abutment surface 229 with a tightening band section 21.
It is supported by two ears 214. This abutment surface 229 is formed on the collar 230 which is designed as an end-side threaded head, which can also be machined with an outer tooling surface for adjustment. The section of tightening screw 216 that follows it penetrates the hole in the other ear 215 with play of movement. The bolt section consists of a thread section 253, which is screwed into the female threaded hole 252 of the bearing pin 251. By rotating the tightening screw 216 with respect to the bearing pin 251, adaptation to different tightening neck outer diameters is possible, for example. The ear 215 has a support portion 254 on the lever 219 side. It has a guide portion 255 which engages between the two fork legs 249, 250 of the hawk 248, which guides the lever 219 in its end region. On both sides of the guide part 255, the bearing 254 has flat bearing surfaces 256, 257 on which the clamping surfaces 246, 247 on the end side of the lever 219 are supported. The support 254 in this embodiment consists of an additional component that is supported by the ear 215, for example fixedly mounted on the ear 215. Adjusting the tightening screw 216 by rotating the tightening screw 216 with a collar 230 as a tightening screw head so that the initial tightening force required in relation to the tightening neck of the machine tool is obtained. You can In this case, the thread segment 253 is screwed into the bearing pin 251 to varying degrees. The lever 219 is then swiveled around the axis 245 for tightening into the tightened position shown in FIG. This tightening surface 24
Due to the increasing eccentric distance of 6,247 from the axis 245, the clamping force is exerted on the bearing surfaces 256,257 and thus on the ear 215. Both tightening band sections 212, 213 are screwed together to the required extent. The protective hood 210 is thereby tightly tightened on the tightening neck. To remove the protective hood 210, rotate the lever 219 outward to release the tightening force. Binaural 214,21 based on eccentric distance
This increases the spacing between the five, which allows the protective hood 210
The tightening force on the tightening neck is relaxed and the protective hood can be removed from the tightening neck. The eccentric disc type clamping device 244 has a particularly simple structure,
Manufacturing cost is low and handling is easy. Also, the protective hood 210 can be replaced without the use of any additional tools. The eccentric clamp 244 can be handled quickly, easily and without special expertise. The "opening / closing" of the clamping device can be performed particularly advantageously when the grinding wheel of the polishing platen is arranged horizontally. The adjustable clamping screw 216 allows the clamping device to be adapted to different clamping neck diameters if required. Advantageously, this adaptation is done without the lever 219 being tightened. In this case, the collar 230 is held by hand, and the tightening screw 216 is adjusted by rotating the collar 230.
It can also be done with tools, for example pliers, if necessary. Like the lever 19 of FIG. 1, the lever 219 has a free end portion 226 for a handle that is easy to grip. The protective hood 310 according to the fourth embodiment shown in FIG. 9 is the same as that of the third embodiment in all important parts. The difference is that the bearing 354 is an integral part of the ear 315 in this embodiment. The ear 315 also has a ridge 358 extruded towards the bearing pin 351 which engages between the two fork legs of a forked fork 348 at the end of the lever 319. , Forming a guide 355 for the lever 319.
On both sides of the ridge 358 are flat support surfaces 356, 357, which are formed by the outer surface of the ear 315 itself. The ridge 358 extends beyond the ear 315 and extends from here to the extent to which the fastening band 313 is connected to the ear. This area is designated by the reference numeral 359 and continues approximately at right angles to the raised portion of the area of the ear 315 (Fig. 10). In this way, the ridge 358 simultaneously serves as a reinforcing rib which reinforces the ear 315 and the area of the fastening band 313 which follows it. Exactly in this range is the eccentric disc clamping device 344
Since a maximum force is applied each time when is operated, a certain amount of deformation force of the tightening band in this range can be effectively suppressed by a simple means. The axial abutment surface 329 of the clamping screw 316 is formed in this embodiment by an annular collar 330, which may be integral with the clamping screw 316, for example. The annular collar 330 is followed by an end section 360, the end surface of which is provided with a slit 361 for hanging the blade of a screwdriver. Tsuba 3
30 and / or the end section 360 may be provided with an outer tooling surface, for example as flattened side portions, so that a tool, for example pliers, may be provided on this outer tooling surface when adjusting the clamping screw 316. Can be multiplied. Alternatively, a screwdriver may be mounted in the slit 361. The lever 319, like the lever 19 of FIG. 1, has a free end 326 for the handle that is easy to grip.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic plan view showing a part of a protective hood for a hand-held machine tool in a tightening position according to the first embodiment, and FIG. 2 is a side view of a part of the protective hood of FIG. 3 is a view of a portion of the protective hood of FIG. 1 seen from the direction of arrow III in FIG. 1, and FIG. 4 is a portion of the protective hood in a state in which the lever is pivoted outward, and is shown in FIG. A schematic plan view of the corresponding part,
FIG. 5 is a schematic plan view of a portion of the protective hood according to the second embodiment substantially corresponding to FIG. 1, FIG. 6 is a side view of the protective hood of FIG. 5, and FIG. 7 is according to the third embodiment. Protective hood,
FIG. 8 is a schematic plan view of a portion substantially corresponding to FIG. 1, and FIG.
FIG. 9 is a side view of the protective hood shown in FIG. 9, and FIG. 9 is a schematic plan view of a portion of the protective hood according to the fourth embodiment substantially corresponding to FIG.
10 is a schematic plan view showing a part of the protective hood of FIG. 9 with the lever removed, and FIG. 11 is a partial view of the protective hood of FIG. 10 seen from the direction of arrow XI of FIG. It is a figure. 10,110,210,310 …… Protective hood, 11,111,211,311 …… Tightening band, 12,112,212,312,13,113,213,313 …… Tightening band classification, 14,114,214,314,15,115,215,315 …… Ear, 16,
116,216,316 …… Tightening screw, 17 …… Clamping device, 19,11
9,219,319 …… Lever.

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Friedrich Heusline               Federal Republic of Germany               Hinterdegen Kertenschutler               C 4 (72) Inventor Vinfried Helm               Federal Republic of Germany               Hitter Dingen Gautenschutler               SE 10 (72) Inventor Manfred Shuttler               Federal Republic of Germany               Hitterdingen Christoph Syutla               45                (56) Bibliographic references Sho 56-166145 (JP, U)                 Actual development Sho 60-161549 (JP, U)                 Actual public Sho 49-4883 (JP, Y1)

Claims (1)

(57) [Claims] A protective hood (10; 110) for a handheld machine tool,
In the type in which the protective hood is tightly tightened to the tightening neck on the hand-held machine tool side by the screw bolt (16; 116) for tightening the tightening band (11; 111) on the protective hood side, the screw bolt (16; 116) a head (18; 118) pivotally pivotable about an axis extending in a direction intersecting the axis of the screw bolt (16; 116), a protective hood without the use of tools A lever (19; 119) for enabling tightening and release of (10; 110), the lever being automatically swiveled and folded back to at least one end position of its swivelable range. Protective hood for hand-held machine tools. 2. Screw bolt (16; 116) has its thread classification (27; 127)
Female thread (28; 128) on one tightening band ear (14; 114) extending from the tightening band section (12; 112) with
Is screwed in and the screw bolt (16; 116) is screwed into the other fastening band ear (15; 115).
Claim 1 characterized in that said head (18; 118) is supported by an axial contact surface (29; 129).
Protective hood as described in paragraph. 3. The thread category (27; 127) and the male thread section (28; 128) belonging to the thread category are fine threads, for example pitch 0.
Protective hood according to claim 2, characterized in that it has 75 threads M8. 4. The lever (19) has two legs (20; 21) of different lengths, bent in the shape of a hairpin, these legs being bent at substantially right angles (22; 23). With corresponding holes (24; 25) in the head (28) of the screw bolt (16)
The protective hood according to any one of claims 1 to 3, characterized in that it is engaged inward. 5. The holes (24; 25) are arranged at right angles to the longitudinal axis of the screw bolt (16) and are spaced apart from each other, and the lever (1
5. The protective hood according to claim 4, characterized in that 9) is forcibly moved into the tightening position by the spring force acting from the shorter leg (21). 6. The lever (119) is formed as a single rod lever and the head (118) as a bifurcated fork (132), and the lever (119) at one end of the head (11).
The support pin (136) penetrating both fork legs (133; 134) in the lateral slit formed between the fork legs (133; 134) of 8) is supported. The protective hood according to any one of claims 1 to 3. 7. A clamping band section (112) having an outer spring (137), one end of which is attached to the protective hood (110).
The other end of the spring is engaged with the lever (119) and presses the lever to the swivel position where the lever is folded inward toward the tightening neck. The protective hood according to any one of claims 1 to 3 or claim 6. 8. A spring (137) is formed as a torsion spring (138) having first and second ends (140; 141), the second
An end portion (141) of the lever is bent, is in contact with the outer rear surface of the lever (119), and has a hook-shaped portion (142) extending laterally with respect to the longitudinal direction of the lever. The hood according to claim 7, which is characterized in that. 9. The hook-shaped part (142) is followed by an end leg (143) bent substantially at a right angle from the hook-shaped part, and the end leg is perpendicular to the extension direction of the lever (119). The protective hood according to claim 8, characterized in that the protective hood is engaged with the side surface of (4). 10. The lever (19; 119) is formed in an arc shape corresponding to the tightening band (11; 111) extending in an arc shape, and extends substantially in the plane of the tightening band (11; 111), and the tightening band is formed. The free end of the handle (26; 1) away from (11; 111)
26) The protective hood according to any one of claims 1 to 9, characterized by comprising: 11. In a protective hood (210; 310) for a hand-held machine tool, in a type in which the protective hood is tightly fastened to a tightening neck portion on the hand-held machine tool side by a screw bolt for tightening a tightening band on the protective hood side, Equipped with an eccentric disc type clamp device (244; 344) that engages with one end of a screw bolt (261; 316) that serves as a tightening bolt, and enables change and tightening and release of the tightening force without the use of tools. However, the eccentric disc type clamp device has an eccentric disc lever (219; 319) which is rotatable about an axis extending in a direction intersecting the axis of the screw bolt (216; 316), and the lever is provided. A protective hood for a hand-held machine tool, characterized in that it is automatically held in its folded-back tightening position along adjacent tightening band sections (213; 313). 12. The eccentric disc lever (219; 319) has its pivot axis (245; 3
45) eccentrically extending with respect to the end side tightening surface (24
6; 247; 346; 347), wherein the fastening surface directly or indirectly abuts one of the fastening band ears (215; 315). Protective hood as described. 13. The eccentric disc of the eccentric disc lever (219; 319) has a slit in the shape of a hawk, and in the range of both hawk legs (249; 349; 250; 350), a lateral axis is formed through the hawk legs. The protective hood according to claim 11 or 12, which is supported on a support pin (251; 351). 14． The bearing pin (251; 351) extends at right angles to the screw bolt (216; 316) and has a female screw hole (252; 352).
The protective hood according to claim 13, further comprising: a screw bolt (216; 316) screwed into the female screw hole. 15. Screw bolt (216; 316) has its head (230; 330)
The axial contact surface (229; 329) of one of the tightening band ears (2
14; 314) and screw bolts (216; 31)
6) play with its threaded portion (253; 353) through the hole in the other tightening band ear (215; 315) with play into the female threaded hole (253; 352) of the bearing pin (251; 315). Claims 12 to 14 characterized in that it is fitted
The protective hood according to claim 1. 16. Bearing part (254; 354) as a bearing stand on the side of the eccentric disc lever (219; 319) of one tightening band ear (215; 315).
Of the eccentric disc lever (219; 31).
9) a guide portion (255; 355) as a guide protrusion engaging between both fork legs (249; 349; 250; 350) and flat supporting surfaces (256; 257; 356; 357) on both sides of the guide portion. ), And the end face of the eccentric disc lever (219; 319) has a tightening face (246; 2).
47; 346; 347) is supported, protection hood according to any one of claims 13 to 15. 17． The bearing part (354) as a bearing stand has a fastening band ear (3
The protective hood according to claim 16, which is an integral component of 15). 18. The tightening band ear (315) is supported by the bearing pin (35).
Guide protrusion (355) deformed by extrusion toward 1)
A ridge (358) forming a ridge, and on each side of the ridge is followed by the outer surface of the fastening band ear (315) forming a flat bearing surface (356; 357). The protective hood according to claim 17, characterized in that: 19. Claim 18 characterized in that the ridge (358) extends from the tightening band ear (315) to the connecting range (359) of the tightening band (311) and forms a reinforcing rib.
Protective hood as described in paragraph. 20. The protective hood according to any one of claims 15 to 19, characterized in that the head (230) of the screw bolt (216) has a tool hanging surface. 21. The head (330) of the screw bolt (316) is formed by an annular collar, and the annular collar is followed by a pin-shaped end section (360), and the end section is a slit on the end surface as a tool hanging surface. (361), any one of claims 15 to 19 characterized in that
Protective hood as described in paragraph. 22. 22. Protective hood according to claim 21, characterized in that the annular collar and / or the end section (360) has a further tooling surface. 23. The eccentric disc lever (219; 319) is formed in an arc shape corresponding to the tightening band (211; 311) extending in an arc shape and extends substantially in the plane of the tightening band (211; 311) and tightens. One of claims 11 to 22, characterized in that it has a free end (226; 326) for the handle, which is remote from the attached band (211; 311). Protective hood as described in paragraph.