US2097655A - Surface grinder - Google Patents

Description

Nov. 2, 1937.

, A. DE MARCHI ET A1.

SURFACE GRINDER Filed Jan. 1e, 1937 2 Sheets-Sheet l Nov. 2, 193;?. A. DE MARCHI ,ET AL 2,097,655

SURFACE GRINDER Filed Jan. 16, 1937 2 Sheets-Sheet 2 z rfc/ 17. Sano/ffl Patented Nov. 2, 1937 UNITEr [STATES PATENT OF SURFACE GRINDER Artudo De Marchi land David A. Sandin,

9 Claims. 'Ihis invention relates to surface `grinding machines such, for example, las used inflni'shing floors, walls, and the like .laid in terrazzo or similar materials. Particularly the invention i provides an improved grinding machine `for simultaneously grinding, collecting and carrying away the .dust produced in the 'grinding and finishing vaction in .the carrying Aout of .grinding or nishing under the dry process .as `distinguished from the wet process, where .Water is employed in the ygrinding action.

Generally stated, the invention consists of the novel devices, combinations of devices, and arrangement of parts hereinafter described ,and defined in the claims.

In a sense the `present invention is in the nature of an improvement4 on or a modification Or refinement of the device or machinedisclosed in the De MarchiiPatent No; 1,936,449, issued of date November 21, 1933,1and entitled Terrazzo grinder". y

In the accompanying drawings, there is illustrated a commercial form of the rimprovedgrinder which embodies what is, at presentconsidered the' most Aapproved form ,or lembodiment of the invention. v l

Referring to the drawings, .whereinflike .,cha'ractersindicate like parts 4throughout:the several views:

Fig. 1 is a side elevation, with some parts broken away, showing the complete grinding machine;

Fig. 2 is an enlarged view partly in side elevation, but partly in vertical axial section, showing the grinding and suction head portions of the improved machine, some parts being broken away; l Fig. 3 is a section taken on the line 3--3 of Eig.,2; and

Fig. 4 is a section taken on the line 4--4 of Fig. 2.

.1 The power device illustrated and preferably employed is an electric motor,`the iixedvor body portion of which is indicated by the character 5 and the rotor shaft thereof by the `character y6. This'motor may be supported in various ways'but preferably and, as shown, is mounted on a trucklike carrier 1, through the intervention of a turntable structure 8. As a means-for transmitting power from the rotor of the motor to the grinding tool or wheel, a flexible transmission shaft 9 iS connected to the rotor 6 of the motor by a suitable coupling `such as that indicated at Ill. At a point close to the coupling I the shaft 9 extends through and is journaled in a non-rotary bearing II thatl isrigidly connected tothe fixed part of vthe motor frame 5, by a yoke I2 or other suitable means.`

The extended portion of the exible shaft 9 is extended through and journaled in a iiexible casing I3, one end of which is anchored to the fixed bearing il by a suitable coupling, such as that `indicated at lli. The flexible shaft 9 and fiexible vcasing I3 are of well-known commercial form, and'hence; the details thereof require no further explanation. Thelength of the said elel0 ments 9 and i3 may varyto suit the requirements of rany particular work. At its extended end the casing i3 is coupled to a bearing tube I5 which, by movements of the flexible casing, is made portable and capable of large range of shifting movement, not only with, but irrespective of movements of the motor. In accordance with this invention the connection between the free or extended end of the `casing I3 and the bearing tube I5is made as follows: a metallic end tube 20 Iii is clinched or otherwise secured to the end of ythe casing I3, and has screw-threaded engagement withan intermediate tubular coupling Il which, .in turn, has screw-threaded engagement ,with the `somewhat enlarged rear endof the bearing tube I5.

' "The grinding wheel or `tool shown is illustrated as and may be assumed to be a carborundum wheel I8 of drum-like form that is detachably secured to a driving spindle I9. This grinding wheel, at one end, has an enlarged recess 20 and in ,its .bore there is inserted a metallic bushing 2| which, in turn, is directly mounted on the somewhat .reduced outer Hendof the spindle I9. By means of a-nut 2,2 applied to the outer end of ,35 the Vspindle I9, the inner end of grinding wheel I8 will be tightly pressed Yagainst shoulder-forming, rib '23 of the'bushng, and the bushing will be pressed against a shoulderZfl 'of the spindlejIQ.

lThe spindlejlextends through and is jour- 40 naled within the bearing tube I5, by suitable means suchasball'bearings `25. The fixed elenrents'of the outer end of the Yball bearing devices 25 areldirectly applied in a collar 26 thatv is screwed onto theadjacentlend of the bearing tube I5. The fixed element of the inner end of ball bearing device 125 is `applied in the somewhat enlarged end of the bearing tube `I5 and is clamped'bet-ween the coupling element Il and the adjacent shoulder.o`f..said tube. AtLits inner end 50 the spindle "I9 `has van outstanding flange 2l against which the-rotaryielement of the inner end ball bearing device 25 engages. Of course, the rotaryelementslofathe ball `bearing devices 25 are rigidlyjappliedon the spindle I9 for rotation 55 therewith. The bearing tube I5 s intended to contain grease or lubricant, and hence, its outer end is shown as closed against the leakage of grease, by a washer 23.

The extended end of the flexible shaft 9 is passed from the iiexible casing I3 proper into the end or terminal tube I6 of said casing, and its end is coupled to the wheel spindle I9 for rotation of the latter and of the grinding wheel, by means of a coupling in the form of a rigid metallic terminal shaft 29. This shaft 29 is formed with a socket into which the end of the flexible shaft 9 is telescoped and there secured by a setscrew 39 or some other suitable means. The reduced end of the shaft 29 is angular in cross-section and is telescoped into a correspondingly formed axial seat of the spindle I9. In this way the iiexible shaft and wheel spindle I9 are connected for common rotation under power transmitted from the motor, and wear or any slight axial movement of the connected parts is compensated for by possible sliding movements of the shaft 29, in respect to the spindle I9.

As already indicated, means is provided for picking up the dust produced by the grinding wheel andconveying the same to a suitable point of discharge. 'As a most eflicient means for accomplishing this result, there is provided a suction fan mounted on the motor frame. This suction fan may be of any approved or suitable type and, as shown, consists of a fan casing 3l directly secured on top of the motor frame and provided Vwith a discharge spout 32 that may lead tol any suitable point or place of discharge, either at the exterior of the room or to a dust-collecting bag, such as frequently employed for similar purposes. The rotor shaft 33 of this suction fan is shown as provided with a pulley 34, over which, and a pulley 35 on the motor shaft 6, runs a driving belt 36. The axial intake 31 of this fan is connected to a flexible air tube 38, the extended end of which is connected to a metallic suction tube 39.

This suction tube 39 extends parallel to the common axis of the elements |5--I9v and by a coupling, preferably in the form of a short tube 49, is spaced from but rigidly connected to a long sleeve 4I that is journaled on the bearing tube I5 and is held against axial movements between the end tube 26 and a shoulder of the tube I5. Adjustably mounted on the front end of the suction tube 39 is a suction-acting nozzle 42, the sleeve-like upper portion of which quite closely fits the projecting end of the tube 39 and the depending portion of which is of segmental form and provided, at its extreme lower edge, with a long intake port 43 that is adapted to be positioned close to' the floor and close to the grinding surface of the wheel I 8. The suction nozzle 42, at its outer end, is entirely closed by an end wall and at its inner end, it is closed, except for the passage that permits the same to be telescoped onto the tube 39. By reference to Fig. 3, it willV be noted that the tube 39 is provided with a segmental port 44 that opens the nozzle always to the interior of the tube 39, irrespective of its various adjustments.

By reference to Fig. 2, it will be noted that the distance between the parallel end portions of the slot 45 are spaced approximately the distance represented by the length of the recess 2U in the outer end of the grinding wheel I8. In practice, it is found that the reduced outer end portion of the grinding wheel will sometimes be broken olf, thereby shortening up the grinding wheel to the extent represented by the depth of the recess 29. When the grinding wheel is complete, the adjustment of the nozzle 42 will be as shown in Fig. 2, but if the reduced end of the grinding wheel be broken off, as above indicated, then the nozzle will be slid toward the left, in respect to Fig. 2, to a position in which the screw 46 will be in the right-hand prong of the slot 45. It will be further noted that when the nozzle is adjusted with the screw in either one of the prongs of the slot 45, the nozzle is capable of oscillatory adjustments to properly position the same in respect to the grinding wheel.

The body of the tube 39 affords a handle that may be readily gripped by one of the hands of the operator, while the other hand is engaged with an extended handle piece 41 that is rigidly secured to' the tube 39 and radiates therefrom. When the device is thus held by the two hands, it is evident that the grinding wheel can be moved over the floor or other surface, at Will, and by oscillatory movements, the nozzle can be held in proper position, in respect to the floor or surface being ground.

Of course, the flexibility of the driving shaft and its casing permit the grinding wheel to be moved over considerable surface without imparting movement to the motor and its truck. The motor and the truck are always free to follow the grinding wheel under pulling action produced through the flexible connections; and with the motor mounted on a wheel truck, the travelling movements of the latter are very easily accomplished. However, with the turn-table connection between the motor and the tru-ck, it is possible, without producing any turning movements vof the truck itself, to cause the motor to follow the grinding wheel in making complete travelling movements of the grinding wheel around a circle; and from this point of view, the pivotal or turn-table connection between the truck and motor, and parts supported therewith, has, in practice, been found highly important.

The improved device is not only of simple construction, Vstrong and durable, but is capable of the various required manipulations performed with the greatest ease and work-producing accuracy, both on floors, walls, coves, cornices, ceilings and the like.

From the foregoing, it will be understood that the preferred form of the device illustrated in the ,drawings is capable of modication within the spirit of the invention herein disclosed and claimed.

In practice we have found that for some work it is highly desirable that very considerable pressure be produced on the grinding wheel. To provide convenient device for manually accomplishingrthis pressure, there is provided an auxiliary or additional handle 48fspaced from but located just above the nozzle 42 and provided with a threaded stem 49 passed through a perforation in the hand piece 4l and provided with a nut 59. This auxiliary handle 48 may be applied, as shown in Fig. 2, it may be reversed and applied in the opposite direction over the body of the suction tube 39, or it may be entirely removed.

It should be either removed or reversed, as in- 75 dicated, Whenever the grinding Wheel has to be passed under an object that Would be engaged if the said hand piece 48 be applied, as shown in Fig. 2.

What is claimed is:

1. In a device of the kind described, a truck, a motor mounted on said truck for horizontal swivelling movements, an extended flexible transmission shaft driven from said motor, a grinding Wheel connected to and driven from the extended end of said flexible shaft, a suction fan mounted on said motor for oscillatory movements therewith, means driving the rotor of said fan from the rotor of said motor, a suction tube associated with the extended end of said transmission shaft and connected to the intake of said fan, by a flexible air tube, and a nozzle head swivelled to the end of said suction tube and closely associated with said grinding wheel.

2. In a. device of the kind described, a rotary motor, a rotary suction fan mounted on and driven from said motor, a flexible tubular casing anchored to and extended from the frame of said motor, a bearing tube connected to the extended end of said casing, a grinding Wheel having a spindle journaled in said bearing tube, a exible shaft extended through said flexible casing and having one end connected to the rotor of said motor and its. extended end connected to the spindle of said grinding wheel, a sleeve mounted on said bearing tube for oscillatory movements, a suction tube extended parallel to but spaced from and rigidly connected to said sleeve, a flexible air tube connecting said suction tube to the intake of sai-d fan, and a nozzle head applied tothe end of said suction tube and closely associated with said grinding wheel, said nozzle head being mounted on said suction tube for oscillatory adjustments toward and from said grinding Wheel.

3. The structure defined in claim 2 in which said suction tube serves as one hand piece and is pro-vided with a radially extended arm that affords another hand piece.

4. The structure dened in claim 2 in which said grinding wheel is of drum-like form having an enlarged recess at its outer end, and said spindle is provided with a nut located within said recess, and in which said nozzle head is mounted on said suction tube for oscillatory and axial adjustments, said nozzle head having a sleeve-like portion formed with a channel-shaped slot and said suction tube having a clamping bolt Working in said slot, the extremities of said slot being circumferential of said tube and being spaced approximately the axial depth of the enlarged recess in the end of said grinding wheel.

5. The structure defined in claim 2 in which the suction tube is provided with an auxiliary handle spaced from but applied over said nozzle head.

6. The structure defined in claim 2 in which the suction tube is provided with an upstanding handle and with an auxiliary hand piece applied to the latter in a position spaced above but overlying said nozzle head.

7. The structure defined in claim 2 in which the suction tube is provided with an upstanding handle and with an auxiliary hand piece applied to the latter in a position spaced above but overlying said nozzle head, said auxiliary handle having a nut-equipped stern passed through a perforation in said upstanding handle and thereby made removable and reversible.

8. The structure dened in claim 2 in which said nozzle head is also mounted for axial adjustments on said suction tube.

9. In a device of the kind described, a truck, an electric motor, the frame of which is mounted on said truck by a turn-table swivel, a flexible casing anchored to said motor frame and extended therefrom, a tubular bearing anchored to the free end of said casing, a grinding wheel having a spindle journaled in said tubular bearing, a exible transmission shaft extended through said iiexible casing with one end connected to the rotor of said motor and with its other end connected to the spindle of said grinding Wheel for rotating said grinding Wheel, in further combination with a suction fan mounted on the frame of said motor, means for driving the rotor of said fan from the rotor of said motor, `a sleeve mounted on said bearing tube for oscillatory movements, a suction tube spaced from but rigidly connected to said sleeve, a flexible air tube connecting said suction tube to the intake di said fan, and a nozzle head swivelled to the end of said suction tube and closely associated with said grinding Wheel.

ARTUDO DE MARCHI, DAVID A. SANDIN.

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