DE7603045U1 - GRINDING MACHINE WITH GRINDING BLADE - Google Patents

Description

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Ref .: G 760 30 45.0 Stuttgart, May 25, 1979 Note: Miksa Marton P 3134 Hgm X / Lö

Representative;

Kohler - Schwindling - Späth
Patent attorneys
Hohentwielstr. 41
7000 Stuttgart 1

f Sanding machine with sanding sheet

* ■ - The invention relates to a grinding machine with a

powered sanding pad with a detachably attached sanding sheet with continuous recesses in the central and in the peripheral area to which the sanding pad passes Connect channels on the back surface of the sanding pad facing away from the sanding sheet Open into a vacuum chamber, which apart from the back of the sanding pad is covered by a machine-fixed housing is limited to the extraction of the grinding dust a supply line leading to a vacuum generator is connected.

^, In a known such machine (US-PS 18 OO 341) the punched sanding sheet is attached to a sanding pad that has a convex surface having. The punchings or bores of the sanding sheet which are in the vicinity of its ^ periphery are attached, align with axially through bores of the rotating driven grinding plate, which open into a suction chamber housing, to which a feed line is connected, which is connected to a vacuum line via a vacuum line Vacuum generator is connected in the form of a suction fan. The suction ensures that

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Annoyances and impairments caused by the generated dust can be largely avoided, as it is sucked off through the bores immediately after it is created. If the known arrangement is now transferred to sanding discs for fine sanding or surface sanding, with the sanding sheet attached to the face of the sanding disc having a grain size lying in one plane, the sanding disc sucks on the workpiece to be sanded and can only be moved with difficulty over the surface to be sanded . The reason for this is the force that is generated by the pressure difference between atmospheric pressure and the pressure between the sanding sheet and the workpiece. Also, grinding dust that reaches the area outside the suction holes is no longer extracted, but rather thrown outwards because of the rapid rotation.

An orbital sander is also known ( ¹³ E-GM 73 46 (...) 228) in which the sanding pad also has radial channels

are incorporated, which open into the outer surface of the sanding plate. With an orbital sander where the

| The disc does not rotate or rotates slowly, the grinding

dust particles do not have a large radial velocity component and can therefore also be detected by a relatively weak suction.

The object of the present invention is to improve the known machine and the grinding sheet so that they can be used comfortably even when using flat sanding discs, there is no sticking, the sanding sheet

ν change is quick and easy and the change

suction is adaptable to the respective needs.

This object is achieved according to the invention in that

[ channels inclined to the axis of rotation are provided,

the is open to the outer surface of the sanding plate that

(f the sanding sheet by means of a

jacket drawn hem and overlaid clamping ring can be attached to the grinding plate, and that the hem is provided with recesses arranged in the area of the mouth of the channels in the jacket surface.

In the case of the grinding device according to the invention, there is an improved suction in the edge area despite the rapid Rotation achieved and combined with the known detachable attachment of the sanding sheet by means of a folded over Hem and overlaid clamping ring. Through the channels inclined to the axis of rotation, which from exit the suction chamber area and open into the outer surface of the sanding pad near the sanding surface, there will be improved suction due to the capture of the grinding dust thrown radially outwards in this area. With such an arrangement However, it did not seem possible to use the well-known hem fastening to be realized at the same time. This has still been achieved by providing recesses in the Hem, which has been found to be due to the fastening located in the radially outer region by means of the clamping ring a twisting between the sanding sheet and sanding pad does not occur during operation, which would have had the consequence that the outer surface openings would have been covered. This way is not only achieved improved suction, but it is too

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the sanding sheet held reliably and a sanding sheet change quickly possible. In addition, the prevailing negative pressure can be achieved through the openings in the lateral surface set by choosing the cross-sectional shape and the number of orifices and the adjoining channels. While with sanding discs where only openings are provided in the sanding sheet surface, the negative pressure -

i fluctuates very strongly in the chamber, depending on whether the y

The sanding sheet is flat on the surface to be sanded |

lies or whether this surface is possibly curved |

or the sanding pad is at an angle |

occupies, is through the | Channels achieved a regulating effect which greatly reduces these fluctuations and which determines and limits the negative pressure.

In a preferred embodiment of the invention, there is one with recesses on the side facing away from the sanding sheet provided cover plate detachably attached. This has the advantage that the inclined channels that one Cleaning are difficult to access if a large amount of sanding dust has settled, can be easily cleaned when the cover plate is removed. For example, they can pierce by means of can be exposed again with a thorn.

The regulation of the appropriate negative pressure for the respective working conditions can, however, also be done by Choice of the appropriate number and cross-sectional size of the channels leading to the lateral surface and opening there also be achieved in other ways. To this end, in a preferred embodiment of the invention a vacuum setting device on the housing

seen. This vacuum setting device, which can be designed differently, can each effective suction pressure can be set so that on the one hand a satisfactory suction is achieved and on the other hand the force pressing the machine against the workpiece is only so great that it stops working with the machine not disabled. Especially with larger grinding or polishing machines where suction openings are in the area of the Grinding surface are provided, the invention makes it easy to move the machine over the workpiece reached away. By adjusting, the user can create a balance between the suction force that the Grinding machine presses against the surface of the workpiece and the suction strength necessary for effective dust removal is required; this allows the user to move the grinding wheel over the surface with sufficient ease Move the workpiece away and there is still a good suction effect with effective dust at the same time distance achieved. ™

Included in preferred embodiments of the invention the vacuum setting device closes the mouth of the supply line from the vacuum generator. By adjusting the slide, whereby the mouth is more or less closed, the acting Conveniently and easily adjust the vacuum. This arrangement is very simple and therefore to be implemented cost-effectively. Another advantage is that the suction pressure can be switched off when the Slide is pushed into a corresponding end position, which can be advantageous when changing the sanding sheet, because when the suction pressure is fully effective, the sanding sheet is pulled in one position against the sanding pad

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can, in which its holes or punchings not align with the holes in the sanding plate. An alignment with full negative pressure prevailing, it could tear or kink or cause other damage of the sanding sheet

In another preferred embodiment of the invention, the vacuum setting device is a valve, the one guided in the wall of the housing perpendicular to this adjustable against the force of a spring There is a screw bolt with a valve disk, by means of which bores provided in the wall of the housing are lockable. By adjusting the spring preload or the distance between the valve plate and the The desired negative pressure can be set on the wall of the housing.

In preferred embodiments of the sanding sheet, the edge thereof consists of a flexible and in particular a textile material. This has been found to be particularly useful.

The grinding sheet can be designed as a circular disk, the circular ring edge of which with the recesses in the form of Perforations is provided. In a preferred embodiment according to the invention, on the other hand, the abrasive sheet comprises a central, circular or annular region with radially outwardly adjoining projections. The projections form the fastening seam, whereas the Areas between the projections form the recesses, in the area of which the mouths of the on the jacket surface ending channels. The grain can be spread over the surface of the central Ee-

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rich as well as the surface of the protrusions. The latter has the advantage that the sanding sheet can be punched out of large webs that already have a Are provided with grain, or can be provided with a grain without the hem being covered got to.

In order to additionally increase the abrasive it is overall measure ^ a preferred Ausführungsfonn with a belast- 'v cash, flexible Rüekeeitenauflage both the central

Area as well as on the projections.

In one embodiment which has proven particularly successful, the projections have a at their free end greater width than in the area in which they adjoin the central section. This has the advantage that the sanding sheet, which can slide on the resilient sanding pad, is a self-centering one It has an effect because every deviation from the central position increases the size of the under the clamping ring causes located width of the projection. Because in this area because of the inward folding and the with it associated reduction in diameter, a puckering of the projections or lobes occurs anyway, this automatically counteracts decentering.

Due to the radial channels inclined to the axis of rotation, a considerable improvement in suction is achieved, because the dust particles thrown out over the circumference of the sanding sheet are also captured. An additional Increasing this effect is achieved according to a preferred embodiment in that at least the for Axis of rotation inclined channels in relation to the radius beam in

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are arranged obliquely in such a way that the channel end opening into the lateral surface is further forward in the direction of rotation than the inner end. These channels can run in a straight line, but they are preferably arcuate

designed. This channel arrangement improves the inflow of the extracted air; This is f. the fact that the outwardly slung Schleifstaub- 'are particulate neither radially nor tangentially thrown away, but its moving direction lies between these two calibration directions. By the mentioned arrangement of the E [Anaele can be achieved in that the channel in the direction \ mouth region with the mean direction of movement of the dust particles approximately coincident, whereby not only the | ^! better suction effect is achieved but also | nor is the effect achieved that there is less dust f.

particles on the canal side facing the rear in running direction | ·>

lower wall. The arched shape of the |

Channels is a favorable flow course of the suctioned f

Air reached. ^f

Further details and configurations of the present invention emerge from the following description Embodiments shown in the drawing * examples in connection with the claims · It is!

s the sanding pad is also referred to as a support cushion, because g it is preferably made of a sponge rubber-like material *. The sanding sheet is also known as the sanding disc j £. It show: %

Pig. 1 shows a side view of a pneumatically driven grinding machine with a support cushion or Sanding pad and a vacuum chamber housing,

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2 shows a plan view of a support cushion or support disk cover,

Fig. 3 is a plan view of the support disc according to Fig. 1,

ig, 4 · a section along the line IV-IV of Fig. 3 »

Fig. 5 shows a section according to Fig «, ^, but in addition with the support ski cover according to Fig. 2,

6 shows a plan view of a grinding wheel with peripheral, flexible support or cover,

7 shows a view of a grinding device with a vacuum chamber housing and with a support disk and a grinding disk attached to it as shown in Fig. 6,

8 shows a partial section through a grinding device

Vacuum chamber housing and support or clamping ~ i ^ plate (support cushion),

9 is a perspective view of a grinding

gerätea with vacuum chamber housing, support cushion and a grinding wheel attached to it with a single central suction opening »

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Fig. 10 partly in view, partly in section

20 cm support disc with stiffening disc,

11 is a side view of a pneumatic 20 cm grinding device with a vacuum chamber housing, 20 cm support cushions and attached ones 20 cm grinding disc,

12 is a perspective view of the vacuum chamber housing according to FIG. 11 in a somewhat enlarged view from above,

13 shows the view of the support chamber housing according to FIG 12 and 13 from below,

Fig. 14 is a view of the 20 cm-support cushion and the stiffening plate according to FIG 10 _o ,.

15 shows a plan view of a grinding wheel with

a single central suction opening and closed peripheral suction openings,

16 shows a section through a support cushion with a soft support ring attached underneath, and FIG a grinding wheel attached to it,

17 shows a partial section through a device for Application of the grinding wheels,

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18 a section through a support cushion similar to FIG

I Fig · 5 "" but only with central suction

P openings,

|, j Fig, 19 is a section through a support ski similar

■ Ι Fig. 18, but only with peripheral

I S eye openings η,

I Fig. 20 is a plan view of a grinding wheel with I <V a single central suction opening and

· § closed peripheral nursing openings on the

* Edge of the sanding surface,

j Fig. 21 is a plan view of a grinding wheel with \ a central portion and at the periphery thereof

subsequent, radially outward-; stretching, spoke-shaped protrusions,

\ and

|, FIG. 22 shows a side view of a disk according to FIG. 21, It is attached to a support by means of an O-ring

I ^ cushion is attached _o

s The pneumatic grinder shown in FIG

f is driven by compressed air, which is supplied by a

I compressed air line 1a is supplied. It includes one

I driven support cushion (support disk, tension disk) 2,

I above the support cover 4 and a suction

I chamber housing 10 with a suction port 13 attached

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are. Sas shown in Fig. 1 support pillow 2 has

peripheral suction openings. Central suction openings can also be provided in the support cushion
be. The Stütakieeen 2 consists of a ribbed,
^a stiffening disc 8, which is attached to a soft, flexible,

supporting cushion 9 is attached, which covers it
(Fig. 3). Sas resilient, resilient gravel 9 can be a
have different compliance, depending on
Appropriateness for the intended use »
case * The support gravel 9 has a circumference
or several peripheral nursing openings 7 on · In operation
the suction connection 13> »i * is a vacuum generator
connected, which generates a negative pressure in the suction chamber housing 10 and the entire support kiaeenayatem. |

The support cushion cover 4 and the ribbed, stiffened |

f end disc 8 usually consist of a half ·? · j '

rigid, somewhat flexible material, which in a ver Ij

bending tends to create an »opening between the supporting Ϊ

gravel cover 4 and the Bodes dee suction chamber |

to form housing 10. In order to avoid pressure |

can be reached along the circumference of the suction chamber: ■ 'housing 10 directly above the support cushion cover 4 an underpressure sealing ring 3 is attached.
s vacuum sealing ring 3 is usually

3 rubber or a similar elastic material,

and shows a certain oversize _s whereby the I.

middle area of the vacuum sealing ring 3 a |

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A bent area is created · Since the under-pressure sealing ring 5 is made of an elastically flexible material, this bent area causes a constant downward force on the Stütaklssencover 4. U »au prevent the vacuum seal a Hing site is" along migrates to the Saugkammergehäua © 10 3 of this along the Umfangea provided below the 14- Sauganschlussea 13 · The ring it ζ 14 may to the 10 Saugkammergehäuse

W be integrally formed ·, it can also be used as a metal ring or the like.

be formed on the periphery of the Saugkammargehäuses 10 is attached «The ribbed, stiffening disc 8 has a groove along its circumference on, which is used to attach a grinding wheel to the Support cushion by means of an O-ring is used as it is afterwards will be described in detail later.

A vacuum shut-off device is also located on the housing 10 appropriate. This device comprises a circumferential recess 70 with a Closure plate 71 * which is arranged behind the slot is. An actuation button 72 is on the lock ( Plate 71 attached to the outside protruding. The Ver

Closing plate 71 is displaceable in the longitudinal direction of the slot-shaped recess 70 »If the actuating button moved into the end position facing away from the suction connection 1J, as shown in Fig. 1, is the suction chamber housing 10 to the outside completely

locked and. ea the full negative pressure generated by the suction connector 15 in the suction chamber housing 10 acts on the suction openings 7. If the actuation button 72 is moved to the other end position, the closure member 71 is moved within the suction housing 10 and closes the suction connection 13. It is advantageous if the negative pressure can be turned off examples _a, then spielaweiae when the abrasive paper on Stiitz-

T ^ \ pillow lst replace 2 _e else would namely

Sandpaper is drawn to the suction openings 7 and could tear or be kinked. By setting of the actuating button 72 and thus the closure plate 71 in Zwieohenatellungen along the slit-shaped Recess 70 can be the strength of the negative pressure can be set in the suction chamber housing 10.

Like from Pig «. 2 shows the support cushion cover A- one or more openings 5 and a central receiving hole 18 on.

^ Fig. 3 shows several centrally arranged suction openings

( 'of the ribbed, stiffening disc 8 and the cushion 9i

as well as the peripheral suction openings 7 in the support kias »Ein Bolt 17 is in the center of the stiffening washer arranged »A support pillow with both central and peripheral suction openings is the most effective Dust extraction. An arrangement of eight central

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and eight peripheral suction ports gives a good effect.

It can be seen from Fig. M- that the central suction openings 6 pass completely through the support cushion 2. The peripheral suction openings 7 connect the upper inner area of the rear side of the stiffening disc 8 with the outer circumferential area of the cushion 9.

As shown in FIG. 5, the support cushion cover M- is provided with the suction ports 5 which communicate with both the central suction ports 6 and the peripheral suction ports 7. With these openings, such a support cushion acts like a rotating vacuum chamber during operation.

A in Fig. Grinding wheel 15 illustrated 6 is used together with a support pad which has both central and peripheral suction openings, as shown in FIGS _o 1 to 5, "The central region of this grinding wheel comprises a circular disc 15 with an affixed peripheral, flexible seam or edge 16. The central disk 15 is provided with a group of suction openings 20 arranged in its central region. The flexible seam 16 has a series of radially extending suction openings in the form

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of Ausaparungen 21, which are approximately evenly along the circumference of the hem or edge 16 are arranged. On the surface of the disc 15 grinding or polishing agent 22 is applied. This area is the actual grinding area.

At the flexible, peripheral seam or edge 16 is |

no abrasive or polishing agent applied. The |

Grinding wheel 15 is also provided with a centering I ₁

Bore 19 provided, which enables the alignment and fastening of the disk 15 and the flexible edge 16 - ■ · relieved on the support disc 2, as it was afterwards

will be explained in more detail. j;

In the case of the | l shown in side view in FIG

Grinding device 1 with the suction chamber housing 10 and ff '

of the support cushion assembly is a grinding wheel | _

according to Pig. 6 on the lower and the upper side |

surfaces of the support cushion attached. The flexible | <

Edge 16 is along the sides of the support pillow | '

folded up and arranged so that the %

savings 21 over the mouths of the peripheral suction §

Openings 7 of the support cushion lie. This affects |

the flexible edge 16 does not impose the flow through |

of air through the peripheral suction openings 7 “The |

flexible edge 16 is by means of an elastic O-ring |

24 held against the sides of the support pillow described in J.

the circumferential groove 23 of the stiffening disc 8 (Fig. 1) *

riiht. The grinding wheel 15 is so on the support pad;

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fastened that the with abrasive or polishing agent vere.6ib.ene side facing away from the support cushion and the Surface facing a workpiece to be ground is"

In Fig. 8 it is indicated how the air flow develops in a grinding device according to the invention when suction is carried out at the suction connection 13. A sufficient negative pressure can be generated at the suction connection 13 by means of a 2 HP industrial vacuum cleaner, such as that used as a portable industrial vacuum cleaner under the Eureka trademark is available. This vacuum cleaner has a suction tube with a diameter of about 30 mm, which is very suitable for attaching to the suction connection. As shown in FIG. 8, air is drawn through both the central suction openings 6 and the peripheral suction openings 7. The air from these two sources then flows through the suction openings 5 of the support pillow cover 4 _O Subsequently, the air in the Saugkammergehäuse 10 is collected and flows through the suction port 13 from. By means of the described system of connecting the suction openings, it is possible to suck in air through the openings 6 and 7 even when the support cushion 2 is driven to rotate rapidly by the drive motor of the grinding device 1, the suction chamber housing 10 not rotating * In Fig. 8 iat also shown how the Stützkisaen 2 on a

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Drive shaft 25 of the grinder 1 "is attached. For this purpose, the drive shaft 25 of the grinding device a »At its lower, free end a chuck 26 which is arranged with a chuck in a clamping bore 27 Tensioning nut is provided "The screw bolt 17 (Fig · 4 ·) of the support cushion 2 is screwed into the chuck 26 and in its end position by means of the in the Clamping bore 27 arranged clamping nut securely fastened.

In Fig. 9, the grinding device 1 with the suction chamber housing 10 and the support cushion combination with the grinding wheel 15 is shown in a view obliquely from below. Eight central suction openings 6 are arranged in a distributed manner in the central region of the cushion 9. They each correspond radially in their position to the peripheral suction openings 7 · ^E s has been found to be useful for the production and attachment of the grinding wheel to coordinate the positions of the central suction openings 6 and the peripheral suction openings radially or in the circumferential direction.

: ⁽ The grinding wheel 15 shown in Fig. 9 has only

[a single central suction recess 28 on and under

differs in this respect from the in

Fig. 6 shown grinding wheel, however Suitable for use in the same way when the six suction openings 20 with the six suction openings 6 cursing. The flexible edge 16 of the grinding wheel 15

is on the support cushion by means of the rubber O-ring 24 attached.

In 3? 10 shows a larger support cushion 29, which, for example, has the commercially available 20 cm diameter. This 20 cm support ski 29 consists of one circular, semi-flexible, sponge-like material, on the upper side of which a stiffening disk 30 is attached is. The Verateifungsscheibe 30 consists of Q a semi-rigid material with only limited flexibility ο a group of central suction openings 31 f extends vertically through the stiffening disk

and the support cushion 29 through a series of peripheral

! Suction openings 32 can be along the circumference of the support pad

sens 29 can be provided the dashed lines in Fig «, 10 indicated, with the

J central suction openings 31 are connected. It will be

if peripheral suckling ports 32 are present, through a negative pressure generated at the top of the suction openings 31 Air through both the peripheral openings 32 and 32.

through the lower end of the central openings 31 angers ^^ sucks. A circumferential groove 42 is formed in the support pad 29

incorporated into Jig. 10 with dashed lines indicated suction chamber housing covers the combination from stiffening disk 30 and support cushion 29.

In Fig. 11 is a 20 cm support pillow along with a Matching suction chamber housing 34 and a pneumatic drive motor 33 shown ,, The compressed air operated pneumatic drive motor includes an air ίί. turbine with an output of about 1.25 hp. One of those

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Compressed air turbine drive iat under the trade name Dotco available and drives a grinding wheel 52a with it a speed of about 1500 rpm at "

The suction chamber housing 34 has a suction connection 35 and a sealing ring 36. The sealing ring consists of Rubber or other suitable elastic material; it can be done by using a reinforcement layer be stiffened from canvas or a similar, suitable material to withstand the negative pressure. the Sealing ring is in place by a rubber band 37 held. The suction chamber housing 34 and the sealing ring cover the stiffening disk 30 «the suction chamber housing 34 · is on the pneumatic drive motor 33 attached by means of an adjustable bracket 43.

A 20 cm grinding wheel 39 is on the 20 cm support pad by means of a flexible 20 cm rim 40 and a 20 cm O-ring 41 held. The openings in the flexible rim 40 coincide with the peripheral ones Suction openings 32, if any, of the 20 cm support cushion.

It has been found in practice that when using a support cushion with only central Suction openings at the "Sin effect of the negative pressure" the suction openings 35 the combination of * the 20 cm support pillow and the grinding wheel 39 with such force is held against the workpiece that it is difficult for the user to use the 20 cm grinder over the

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Move away the surface of the workpiece. Accordingly, the grinder manually, conveniently over the workpiece To be able to move away, it is necessary to have an adjustable suction pressure control valve 38 on the Provide suction chamber housing 34 · With its help the suction force in the suction chamber housing 34 can be regulated so that the grinding device only with moderate force is pulled against the workpiece surface. If, on the other hand, there are peripheral suction openings

\ ) the one, then the one pressing against the workpiece surface

Force negligible and a suction pressure control valve 38 is not necessary

In Fig. 12, the suction housing 34 with the sealing ring 36 I and the elastic band 37 in place in shown perspective view from above. The adjustable suction pressure control valve 38 comprises one Screw bolt 38a which is surrounded by a helical compression spring «. A group of small control valve holes is incorporated into the suction chamber housing 34. The remaining parts of the suction pressure control valve 38 are inside the Suction pressure housing 34 arranged, which is in the lower

'is shown according to FIG. The bolt 38a

is fitted into a control valve nut 47, the one Control valve disc 46 holds in contact with the surface of the suction chamber housing 34. During operation, if inside the suction chamber housing 34 via the suction connection 35 a negative pressure is generated, the Control valve disc 46 against the action of the spring

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pulled inward, creating a gap between the suction chamber housing 34 and the control valve disk opens · This allows air through the control valve bores 45 into the interior of the suction chamber housing 34 which lowers the negative pressure inside to a certain extent «The extent of the lowering can by the user of the grinding device by screwing in or unscrewing the combination of screw bolts 38a and control valve nut 47 can be adjusted, whereby fci "changes the preload of the helical compression spring 44

V will. The preload of the helical compression spring 44

regulates the negative pressure in the

Suction chamber housing 34 adjusts.

jjj In Fig. 13 a clamping slot 48 is also shown,

which is provided in the side wall of the suction chamber housing 34. A hexagon socket wrench or another suitable tool can be inserted into the suction chamber housing 34 through this clamping slot 48,
in order to be able to tighten the support cushion 29 on the drive shaft of the drive motor 33.

y In Fig. 14 is shown in detail how the

peripheral suction openings 32 in the 20 cm support lake with the central suction openings 31 are connected.
Because of this connection, the negative pressure acts both for the peripheral suction openings 32 and 32
for the suction openings 31 through the central openings 31. The peripheral suction openings 32 can directly radially with a corresponding

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Eentralen suction port 31 be connected. It has been found, however, that due to the rotation of the Stütakisens 29, which rotates at about 150 rpm, it is possible to improve the suction effect through the peripheral suction openings 32 by utilizing the rotation effect of the support cylinder 29. This is achieved by the peripheral suction openings are connected to the corresponding central suction openings which immediately precede the radially assigned peripheral suction openings 32. This connection system gives the arrangement the appearance of a spoked wheel (or the rotor of a centrifugal pump or a centrifugal compressor). The channels ^ Q connecting the openings 31 and 32 to one another are shown in broken lines in the support cushion 29 in FIG. A screw bolt 49 is also shown, which is used to fasten the support cushion 29 to the shaft of the drive motor 33 (FIG. 11) β

A 20 cm grinding wheel with central suction openings that correspond to their position with central suction. Openings 31 of the support cushion 29 correspond to _s

('and the further peripheral suction openings on the flexible

Has edge, which in their position with the peri-

|; outer suction openings 32 of the support cushion 29

pond with a corresponding 20 cm grinding

device used »Such a grinding wheel can be about axifweise the same appearance as that shown in FIG Grinding wheel »However, it can also be a

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modified embodiment with only one central opening can be used. This central opening allows air to pass through unhindered central openings 31 of the 20 cm support cushion through suction. Another possible embodiment of a grinding wheel is shown in FIG shown. In this embodiment has a grinding wheel 51 has a single central opening 58, but a flexible edge 52 has instead of elongated incisions, which are located radially in the outer region of the flexible tape extend, as in Fig. 6, circular openings. Air can pass through these openings 53 peripheral suction openings 32 of the 20 cm support pillow to be sucked through »

It goes without saying that other embodiments and designs of grinding wheels can also be used according to the invention. For example, the grinding wheel can be designed as a circular disk with or without a central suction opening, depending on whether a corresponding suction opening is provided in the support cushion or not. Such a grinding wheel is adhered directly to the lower surface of the support pillow, wherein a flexible edge 52 can be omitted, however, _o A with the adhesion of a grinding wheel to the Stützrkissen disadvantage associated is that the adhesive

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collect in the central suction openings 31 and this can clog «, In addition, the hardened adhesive builds up on the surface of the support disc making their surface uneven, reducing the life of the sandpaper grinding wheel leads o

Sometimes it is necessary to carry out special grinding work that the support cushion is particularly soft

y <'■■ to train. Usually this is achieved by

that a soft ring pillow ^ A- is used. This ring cushion 5 ^ - consists of a sponge-like material that has sufficient flexibility and deformability. Such ring cushions ^ A- can be conveniently used in the grinding system described above. In FIG. 16, which shows a section through a support cushion arrangement similar to FIG. 5, it is shown how the ring cushion 54 is arranged under the cushion 9. The annular cushion ^ A- has a central opening and is by the grinding wheel 15, which also has a single central opening, also fixed abrasive discs of the type shown in Fig. 6 can

V also together with a ring pillow 5 ^ - use

find as long as at least one suction opening is provided is so that the central suction openings of the support cushion can fulfill their function. The grinding wheel 15 is attached to the support cushion by means of the flexible edge, which is secured by a rubber O-ring 24- on his Space is held as previously described.

About attaching or mounting a grinding wheel To facilitate attachment to a support cushion, an attachment or mounting device was developed which is shown in Fig. 17 is shown «This device is so constructed that with it a grinding wheel with a flexible edge 52 together with a ring cushion 54-an a 20 cm support cushion 29 can be attached, which is reinforced by a stiffening disk 30. It goes without saying that minor modifications can be made to this γ Λ device to suit them

to be able to use smaller dimensions of support cushions with and without ring cushions. This assembly device comprises a housing 59 »which has approximately the shape of a hollow cylinder, in the center of which a coaxial one Centering mandrel 55 is attached. The centering mandrel 55 is surrounded by a sponge spring 56 which consists of an elastically resilient material. For example, flexible polyurethane foam is suitable as material for the spring 56 »it could However, a helical spring can also be used. A centering plate 57 is on the sponge spring 56 intended. This centering plate is designed in such a way that it has a single central opening 58

facing grinding wheel with flexible edge 52 and a ring cushion 5 ^ accommodates. An O-ring 4-1 is placed around the wall of the housing 59 in the manner shown. The grinding wheel 52 and the Ritig cushion 5M

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are in the manner shown on the centering plate 57 placed. 'Then there are 20 cm' support pillows-129 and i the stiffening disk 30 on the Centering mandrel 55 inserted.

The flexible edge 52 is thereby over- the S does akissen 29 pulled by daa support pillow? 9 together with dea ringkisaea. 54, the edge 52 and the centering plate 57 with the sponge spring 56 together

1-) is pressed down until the circumferential groove

in the lateral surface of the support cushion 29 is approximately aligned with the edge of the housing 59 »In this position, the rubber O-ring 41 is rolled upwards from the housing 59 and snaps into the circumferential groove 42, whereby it the flexible edge 52 against the jacket dea support cushion 29 presses. In FIG. 18, a support cushion 60 is shown in section, which has central openings 61 alone. It has been found that such a support cushion with only central openings 61 removes dust from the workpiece very effectively, although a support cushion with both _{f )} central and peripheral suction openings can be used

turned out to be the most effective. The support pillow is provided with a cover 62, the function of which is also performed by a suction chamber housing 10 (FIG. 8) can be that bia to the periphery of the support cushion extendsο

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In Fig. 19 a support cushion 63 is shown in section, which only has peripheral suction openings 64. Such a support cushion also "leads to the removal of the abraded material from the Surface of the workpiece for good results. The suction openings 64 along the perimeter of the support pillow in the vicinity of the surface facing the workpiece create an arching effect on the Surface of the workpiece that is similar to the effect that the device according to the parent application generated. However, a support cushion with only peripheral suction openings often does not have the serious side Disadvantage that the grinder only works with manual Contact pressure must be held against the workpiece Although peripheral suction openings are also effective, the particularly preferred embodiments of support cushions have both central and peripheral suction openings. In FIG. 19, a cover 65 is also shown, as it is also shown in FIG Fig. 18 is shown, and also when using a suction chamber housing that extends up to extends to the edge of the support cushion, are omitted

Fig. 20 shows a grinding wheel 66 with a single central suction recess 69 »a flexible one Edge 67 and a series of peripheral suction openings 68,

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which are arranged in the circumferential area of the grinding wheel 66 and not in the adjoining flexible edge 67 (as in Pig. 6 or 15). This type of grinding wheel is intended for use with a support pad which has peripheral suction openings which open in the vicinity of the circumference on the underside of the support pad and not in the shell surface, as is shown in FIGS. 1, 4, 5 and 7, for example. Arranging the Saugw ^r N openings 68 in the actual grinding region of the

Washer 66 can occasionally cause difficulties |

lead when these openings become sharp Projections on the workpiece get caught, which can tear the disc, but it is in some Cases of advantage when the suction openings 68 are located in the underside circumferential area of the grinding wheel because it improves the suction effect.

Fig. 21 shows a grinding wheel 77 'which consists of a central circular portion 78 having a Heihe of radially outwardly extending projections \', that of the circular along the periphery

Section 78 are arranged »A centering hole is incorporated in the middle of the circular section. The projections 76 are on their outer, free end wider than where it adjoins the circular section 78 »This achieves

that the projections 76 less easily under the Slide out the O-ring when the grinding wheel 77 attached to a support plate by means of an O-ring " will.

Reinforcing backsheet, not shown, is adhesive or otherwise suitable means attached to the rear of the circular section 78 and the projections 76.

y This rear reinforcement increases the stability

^^ the grinding wheel and its resistance

against tearing,

A grinding wheel 77 with the circular section 78 and the projections 76, as shown in FIG. Abrasive is both on the circular. shaped section 78 and applied to the projections ^ the latter supports the retaining effect of the O-ring. As can be seen from the drawing, the edge of the circular portion 78 is mild Y ι fügig around the edge of Stützkisaens 7 · ^Z - round to

pulled up so that there is no sharp edge on the edge of the support cushion, the cause of scratches and

Could be shouting "

Some examples are given below that demonstrate the effectiveness of grinding devices according to the invention with suction openings in support ponds and grinding wheel to demonstrate"

example 1

A hood from a Ford-Automobila, built in 1965 * with two layers of base coat and four top coats of a green synthetic resin paint (on acrylic resin base) was sanded with a 12.5 cm sanding disc with 120 grit, which was driven by an oribital sanding motor driven by compressed air at a speed of about 8000 RPM was driven. ψ The oribital grinder was a product of the company

Hutchins Manufacturing Company, Paaadena, California. 120 grit sandpaper is generally used for ■ sanding work in automobile workshops. To generate the negative pressure on the support cushion, a portable 2 PS induction vacuum cleaner was used as the negative pressure generator used as it is commercially available under the name Eureka. The vacuum connection had a diameter of about 30 mm.

The support cushion and grinding wheel each had eight central and eight peripheral suction openings, the latter in the surface of the support cushion or the flexible edge of the grinding wheel

) were arranged. The central suction openings in the support

pebbles pulled the detached particles through a central hole in the ring cushion, whereas through the peripheral suckling openings arranged along the perimeter of the support pillow, all on the edge dust escaping from the rotating grinding wheel was removed "

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The suction created by the central suction openings and exerted on the grinding device made it easier to hold the grinding device a and the grinding wheel on the hood, so that it was very easy to control the movement of the grinding device manually

Using the grinding system described, it was easily possible to cover a considerable area of the four-layer topcoat and the two-layer primer

\, dation of the hood can be sanded off in a relatively short time

The most surprising feature of the sander, however, was that virtually no dust escaped as it passed through the suction openings of the support cushion has been sucked in. This was the case even when the edges of the Hood were ground, with a certain area of the grinding wheel extending over the edge of the hood extended. The generated dust was only visible for a moment before it entered one of the suction openings the support disc was pulled in »Another and surprisingly eye-catching one The property of the grinder was that it was practical no dust adhered to the hood due to electrostatic attraction. You could use your finger Stroke along the sanded surface of the hood without leaving a noticeable trace of dust was visible to the finger, although the varnish abraded by the sander was a dark green color.

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By means of an air pistol fed with compressed air of about 20 atmospheres, no dust could be blown off even when the hood was stopped tightly. A very slight hint of dust could be j wiped with a polishing cloth _o

The grinding wheel could move from the support cushion Switching off the negative pressure in the housing can be easily removed by moving the operating button ■ ^. and be replaced by a new pane »

Example 2

It has the same arrangement used in Example This time, however, was removed for demonstration purposes of the vacuum cleaner and the support cushion no negative pressure supplied _o The results were impressive. A significant amount of dust was produced by the grinding wheel in about 15 to 30 seconds. Piles of dust were left on the surface of the hood. In addition, a significant amount of dust was floating in the air, affecting it

\ Working conditions at work because an inhalation

of the dust was inevitable. Some of the dust floating in the air settled on hands and Remove clothing from anyone standing around 3 to 5 m away. A substantial .extension the demonstration experiment would not have been possible because of the large amount of dust generated.

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Example 3

Another area of the Ford truck hood mentioned in Example 1 was made with a 20 cm grinding wheel ground by a 1.25 hp compressed air turbine drive was driven by the Dotco company

! was produced. The grinding wheel had one

120 grit o A sponge ring was inserted between the support disc and the grinding disc. The support disc only had central suction openings. ) The central recess in the grinding wheel

was about 12.5 ^{cm in} diameter. The disk was driven at about 1500 rpm. Using a 2 horsepower Eureka brand vacuum cleaner, it was possible to sand the green paint off the hood with only minimal manual force required to move the sander across the hood surface. The sanding wheel moved slightly across the hood surface and did not have to be excessively hand-pressed to keep them in contact with the surface of the hood »Beyond. practically no dust remained on the surface of the

Car hood back and there was practically no dust in the atmosphere.

Example 4

The same experiment as described in Example 3 above

was implemented with the amendment that the

30 mm connection of the Eureka vacuum generator from.

The suction chamber housing of the 20 cm grinder was separated. The operational difference became apparent immediately. The user had to manually apply a force of about 5 kg to keep the grinding wheel in contact with the surface of the car hood. It was also a considerable force erforderlichj about the grinding wheel at the surface of the car hood to move along, within about 15 to 30 seconds \ considerable amount of dust has been ejected, some of which in

Form of piles of dust remained on the surface of the car hood and partly in the surrounding area Air was expelled, where the dust stayed for a long time,

Example 5

i \; A rectangular plate (chipboard) of about 13 now

■]., Thickness and an area of about 4-5 cm by 75 cm

'f with a 12.5 cm sander with sandpaper with

,, 220 grit sanded. The support pillow had

f both central and peripheral suction openings.

\,! Plastic sawdust obtained by cutting under

plastic available under the trademark nylon

| that was holding was up along the edge of the panel

scattered and had a width of about 5 to 10 cm along the edge of the plate on o When the Vacuum generators were on about 3 meters in the plate

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one side sanded away in about 50 ms 60 seconds. ] f \ Practically the whole of the 12.5 cm

Grinding wheel wood flour produced »withdrawn through, the support pillow therethrough rapidly Moreover hinauB was AUOH daa Eunat8toff-" sawdust _"f that was scattered along the edges of the plate through which I

? Suction width deducted in "inen range of about 5" to 10 cm 'along the edge of support pads and grinding wheel "|

Example 6 f

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The same plate as described in Example 5 |

was used in this experiment. However, |

the 20 em-

Grinding wheel according to Example 3 used instead

of the 12.5 cm Schleifera. The sandpaper had one

16 grit. At the suction connection of the 20 cm grinder

no negative pressure was maintained. Inside

of about 15 seconds became an amount of about

3/4 cup of coarse wood dust created by the grinder.

This wood flour stayed on the surface and along it

the edges of the plate.

It then became the suction connection on the 20 cm sander made and the amount of about 3/4 cup of coarse Wood flour is sucked up through the suction openings of the support cushion within a few seconds. In a subsequent Sanding the edges of the panel with the

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20 cm grinders were even used on an overhang the grinding wheel about 10 cm above the edge of the plate hir ^ e none of that caused by the rotating Grinding wheel produced coarse wood flour “but it was thrown out entirely by the different suction openings of the support cushion. You could see that gross Sawdust up to approximately 5 o ^ from the edge of the grinding wheel flew away, whereupon then the suction effect

/, - outweighed the grinder and put it in one of the openings

the support disc was pulled in »

Another characteristic of this experiment was that if there was no negative pressure, the grinder would with a force of about 5 kp manually against the Surface of the plate had to be pressed. Considerable force was also required around the 20 cm sander over the surface of the Move the plate away. When the vacuum was switched on, only very little manual force was required required to hold the 20 cm sander against the surface of the plate and attach it to the ('To move along the surface of the plate.

Example 7

The same grinding system as in the example was used on the car hood of a Ford already mentioned in example 1 1 used again, but under use

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a support pillow with only central suction openings.

On the Sohleifer exerted suction holding it with the grinding wheel so strongly to the hood, that it was possible, the movement of the slider along the surface with the fingertips to controlling this case, a substantial area of the four Decklaokschiohten and the two Grundiersohiohten the hood in a relatively sanded off in a short time. Although only central suction openings were provided in the support cushion, no dust was released because all dust was drawn in through the system of central suction openings in the support cushion of the sander. This was the case even when the edges of the hood were ground with some area of the grinding wheel extending beyond the edge of the hood. All of generated dust was visible only a brief moment for ¹ before it was drawn into one of the central suction apertures of the support cushion. A small amount of dust, but greater than that in Example 1, adhered to the hood due to green electrostatic attraction. If you wiped your finger over the sanded surface of the hood, only a small amount of dust remained on the finger »

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Example 8

Another section of the Ford hood mentioned in Example 1 was made with a 20 cm grinding wheel sanded by a 1.25 hp compressed air motor The support pillow had both central and peripheral suckling openings on. The grinding wheel was 120 grit. A sponge was between the 20 cm support ski:> sen and put the 20 cm grinding wheel. The central one opening in the grinding wheel had a diameter of about 12.5 cm. The grinding wheel was made with a Speed of about 15ΟΟ rpm driven. When using of the mentioned 2 HP Eureka-Saugera it was possible to sand off the green paint from the hood, however ά .... β full manual pressure of about 5 kp applied needed to move the sander across the surface of the hood. The ones from the central and peripheral orifices developed suction was so effective that practically the whole of it was rotating Dust generated by the grinding wheel was removed. Only a small amount of dust remained on the hood, presumably due to electrostatic adhesion.

Example 9

Another section of the car hood mentioned in Example 1 was sanded with a 20 cm sanding disk, which was driven by a 1.25 HP compressed air motor from Dotco »The suction chamber housing

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the 20 cm sander was with a built-in Suction control valve fitted «, The grinding wheel had a grain size of 120. A Schwamioring was between the 20 cm support cushion and the 20 cm grinding wheel inserted. The support pillow only had central suction openings. The central recess in the grinding wheel was about 12.5 cm in diameter. The disk was driven at about 1500 rpm.

** ■ Using the 2 HP Eureka suction cup it was possible to

sanding the green paint off the hood, two fingers were sufficient to move the grinder. The grinding wheel controlled by the two fingers moved slightly over the surface of the hood and became very little manual force is required to keep the grinding wheel in contact with the surface of the viagen hood. In addition, practically no dust remained on the surface of the hood, and practically none got through Dust in the atmosphere.

( Example 10

The same grinding arrangement as in Example 1 was used reused, however, the rubber sealing ring was used between the suction chamber housing and the support cushion removed. As a result, secondary air was immediately sucked into the suction system and the suction openings became ineffective in the support cushion and the grinding wheel,

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whereby they do not remove the dust generated by the rapidly rotating grinding wheel. This experiment demonstrated the great importance of a good seal between the non-rotating suction cup housing and the rotating support cushion _{or the like}

From the above it follows that it is possible to make changes and modifications to the invention Sanding system without the frame to leave the invention »For example, grinders with suction chamber housing, support cushions and Grinding wheel with suction openings and channels in it not only for rotating, but also for vibrating | and can be used with an oscillating movement of the support cushions, as long as there is a good one Vacuum seal between the suction chamber housing and movable support cushion.

Claims (1)

i · if 'ff · ■ «■! M " · · f * ill • I «« "rf · 14 y * t »fl · ♦ · I Ol ( ft Ref .: G? 6 03 045.0 Stuttgart, May 25, 1979 Note: Miksa Marton P 3134 Hgm Protection claims 1. Sanding machine with a powered sanding plate with a detachable sanding sheet with continuous Recesses in the central and in the peripheral area, to which the sanding pad penetrates the channel Connect the Q channels that are connected to the sanding sheet turned, back surface of the sanding pad Open into a vacuum chimney which, apart from the back of the sanding plate, is covered by a machine-fixed housing is limited to the suction of the grinding dust leading to a vacuum generator The supply line is connected, characterized in that channels (7 or 50 or 64) which are inclined to the axis of rotation are provided which open into the outer surface of the sanding plate (2) that the sanding sheet (15 or 51, 52 or 70, 71, 72) by means of a hem (16 or 52 or 62) drawn over the sanding pad shell and overlying clamping ring (24 or 41 or 75) / can be attached to the sanding pad, and that the hem with in the area of the mouth (7 or 21 or »32 or 64) of the channels in the circumferential surface arranged recesses (21 or 53 or 71) is provided. 2. Grinding machine according to claim 1, characterized in that that on the side facing away from the sanding sheet a cover plate (4) provided with recesses (5) is releasably attached. ■ Γ · I · fill III) Il f * · «till» 1 I. • "I ·> · Il J II« ••• it I 3. Grinding machine according to claim 1 or 2, characterized in that that on the housing (10 or 34) a vacuum setting device (70, 71, 72 or 38) is provided. 4. Grinding machine according to claim 3, characterized in that the üunterdruckeinstelleinrichtung (70, 71 »7 ² ) a the Mündimg of the supply line (13) from the vacuum ~ Producer closing slide (71) includes. 5. Grinding machine according to claim 3, characterized in that the vacuum setting device (38) is a Valve is made up of a in the wall of the housing (34) perpendicular to this against the force of a spring (44) adjustably guided screw bolts (38 a) with a valve plate (46), by means of which in the Wall of the housing (34) provided holes (45) can be closed. 6. Grinding machine according to one of the preceding claims, characterized in that the grinding sheet has a ι ^ central circular or circular area with comprises projections (16 or 72) adjoining it radially outward. 7β grinding machine according to claim 6, characterized in that that the abrasive sheet grain both over the surface of the central area (70) and the Protrusions (72) extends 8. Grinding machine according to one of the preceding claims, characterized in that the grinding sheet with a resilient, flexible backrest dd - ··· ■■ ι ι I ft ' • ~ · · ■ » <<(CtI C, «· · C I I Ü 't -J> 1 ι Cl U - 3 - is provided both in the central area and on the projections sj ,, or on the hem and this rear side support J forms the projections (16 and 72). 9. Grinding machine according to one of the preceding claims, characterized in that the projections ^rt (72) of the grinding sheet (70) at their free end, ι have a greater width than in the area in ^& which they to the central portion (71). 10. Grinding machine according to one of the preceding claims, characterized in that at least the to the axis of rotation inclined channels (50) opposite the $ Radius rays are arranged obliquely in such a way, | that the opening into the lateral surface end of the channel (32) {continues in direction of rotation forward than the inner end. v> 11. Grinding machine according to claim 10, characterized in that the channels (50) extend in an arcuate manner are designed.