US2968897A - Machine tool - Google Patents

Description

Jan. 24, 1961 c. HAMMOND MACHINE TOOL Filed May 7, 1959 INVENTOR, LEE 6. HAMMOND ATTOENEV United States Patent MACHINE TOOL Lee C. Hammond, Kalamazoo, Mich, assignor to Hammond Machinery Builders, Inc., Kalamazoo, Micln, a corporation of Michigan Filed May 7, 1959, Ser. No. 811,703

Claims. (Cl. 51-263) This invention relates to abrasive belt machines, and particularly to a structure for use therein which will enable the belt to be run wet without unreasonable inconvenience or unpleasantness to the operator.

In the application of a cooling and/or cutting oil, or other liquid, to an abrasive belt, it is and has been well known that a major problem in this kind of operation is the spraying and splashing of the liquid onto the operator and onto the floor around the machine. Particularly, the liquid often splashes from the belt onto the table and thence back against the hands or onto the clothes of the operator or onto the floor. Further, a large quantity of such liquid on the belt is often removed from the belt by the workpiece but without appreciably diminishing its velocity and hence travels away from the belt and against the hands or onto the clothes of the operator or onto the floor. Many kinds and types of shields have been devised and are well known to the trade but none of them, insofar as I am aware, has been able to solve the problem. In fact, in many cases where wet grinding has been used, the operator has had to wear rubber gloves and an apron, and has often in addition had to stand on a rack, in order to avoid excessive subjection to cooling and/ or cutting liquid. Therefore, while wet grinding has been long known, is desirable in many cases and essential in many other cases, it has always been inconvenient and'unpleasant for the operators because of their subjection to constant splashing of the cooling and/or cutting liquid as above described.

A further problem in the use of an abrasive belt consists in the long recognized fact that a more rapid and at the same time a better, grinding operation can be carried out if a much larger volume of cutting and/or cooling liquid is used than is now usual. However, with conventional equipment, it is virtually impossible to use such a large volume of liquid inasmuch as the amount thereof which would be splashed back and against the operator would render such use prohibitive. the present equipment makes it necessary to hold the volume of such liquid at such a level that the amount splashing back against the operator can be tolerated. Thus, the amount supplied to the work is considerably less than would be useful. Accordingly, it is desirable to provide apparatus which will make possible the use of a much larger volume of cooling and/or cutting liquid than is possible in present conventional practice without simultaneously raising the amount splashing back against the operator to an intolerable quantity.

Accordingly, the objects of the invention include:

1) to provide a device useable with an abrasive belt type of grinding machine for preventing the cutting and/or cooling liquid used therewith, even though used in large volumes, from being directed in any appreciable amount against the hands and clothes of the operator or on the floor;

(2) to provide an attachment for a belt grinding machine which will both direct cutting and/ or cooling liquid Therefore, a

against the belt and will also protect the operator from liquid being thrown against his hands and clothes and will keep the floor dry around the machine;

(3) to provide a device, as aforesaid, which will permit an extremely large volume of cutting and/or cooling liquid to be discharged against the belt and yet without any appreciable amount thereof striking the operator or the floor;

(4) to provide a device, as aforesaid, which will in no way restrict the operators ability to move the work toward and away from the belt or back and forth across the face of the belt;

(5) to provide a device, as aforesaid, which will provide a minimum of restriction to the operators visual control over the work. and, to the extent that such visual restriction is unavoidable to confine it to circumstances where it can be tolerated;

(6) to provide a device, as aforesaid, which can be readily attached to a wide variety of platen belt grinding machines and which can be easily modified to fit a still wider variety of machines;

(7) to provide a device, as aforesaid, in which the liquid dispensing unit and the operator protecting unit are associated together and may be attached to the grinding machine by a single bracket and both will be adjustable up or down at the same time with this single bracket;

(8) to provide a device, as aforesaid, which will prevent liquid which is deflected off the belt and strikes the table from rebounding against the operator or onto the floor;

(9) to provide means which will prevent liquid which is deflected from the belt by the workpiece from striking the operator or going onto the floor;

(10) to provide a device, as aforesaid, which will be of suflicient simplicity that its cost is negligible as compared to the cost of the entire machine; and

(11) to provide a device, as aforesaid, which can be supplied as a part of a new machine or which may be easily attached to an old machine.

Other objects and purposes of the invention will become apparent to persons acquainted with devices of the general type upon a reading of the following description and inspection of the accompanying drawings.

In the drawings:

Figure l is a front fragmentary view showing the table and the portion of the belt grinding machine above the table, said machine being fitted with an attachment embodying the invention.

Figure 2 is a fragmentary view of the leftward side of the machine shown in Figure 1 and presented on a smaller scale than Figure 1.

Figure 3 is a section taken on the line IlI-III of Figure 1 and presented on a larger scale than that used in Figure 1.

Figure 4 is a section taken on the line IVIV of Figure 3.

General description In general, the invention consists of placing a perforated tube on a bracket and arranging the bracket to hold the tube shortly above the normal position of the work. The axes of the perforation are arranged at from about 45 to about 60 with respect to the surface of the belt. Liquid is supplied to said tube for discharge against the belt at a relatively moderate pressure, so that the liquid lies against said belt and does not rebound appreciably therefrom. Means are provided for ready cleaning of the perforations. The tube is also utilized for the support of a flexible and preferably transparent curtain which hangs from the tube to a point in contact with the work and extending across, and preferably slightly beyond, the full width of the abrasive belt. The curtain being flexible the work can be pushed along the table through and under the curtain into contact with the belt, PPQW from S d to id ere n if esir d. and he urteia will soai r its t h w r sutfic entl l e that no appreciable amount of liquid will be permitted to strike the operators hands or clothes or will escape onto the floor. Further, where appropriate, the curtain can be cut to fit a given workpiece'as closely as desired.

Detailed description In the description of a preferred embodiment of the invention, certain terminology will be used for reference purposes which will be recognized solely as descriptive and having no limiting significance. Thus, the terms upward and downward, and derivatives thereof and words of similar import, will refer to the apparatus when in a normal position of operation and as shown in the drawings, namely, with the working surface of the belt positioned substantially vertically and running downwardly. The terms rightward and leftward and derivatives thereof and words of similar import, will refer to the rightward and leftward side of the machine viewed by the operator when facing it in a normal position of use, namely, the position of the apparatus as appearing in Figure 1. The terms inward and outward and derivatives thereof and words of similar import will refer to directionstoward and away from the geometric center or the apparatus. The terms forward"'and rearward and derivatives thereof and words of other similar import will refer to directions perpendicularly toward or away from the working surface of the belt, namely, to directions in which the work moves on the table as it moves toward and away from working contact with the belt.

In the drawings there is shown fragmentarily a conventional belt grinding machine, which may be of any of several types, such as that shown in US. Patent No. 2,612,007 or in Robischung application Serial No. 738,- 869, now US. Patent No. 2,900,766. In this machine, an abrasive belt 1 of conventional size and type is supported around a pair of pulleys, of which one appears at 2, and is covered by a suitable hood or shield 3. Suitable power means, not shown, are provided to rotatively drive one of said pulleys in a conventional manner. A table 4 is provided for support of the workpiece and, if desired, said table may be vertically adjustable around an axis lying in or adjacent to the working surface of the belt in any convenient manner, such as by the slot and bolt arrangement generally indicated at 6. A platen 7 (Figure 3) is provided against which the belt 1 runs to provide suitable backing for said belt as a workpiece W is pressed against it.

A bracket 8 contains a slot 9 through which extend suitable wing-studs 11 and 12 by which said bracket is adjustably fastened to the hood 3. At the lower end of said bracket 8 there is located a header 13 extending sidewardly therefrom and across the face of the abrasive belt 1. Said header contains a bore 14 closed at one end by a suitable plug 14a, and having a series of small drilled openings 16 by which cooling and/ or cutting liquid introduced into said bore 17 under pressure may be discharged against the face of the abrasive belt 1. A pair of further bores 17 and 18 are provided for receiving liquid to be introduced into the bore 14 and for etfecting introduction thereof into the center of the bore 14. A threaded nipple is threaded into the leftward end of the bore 17, receives the lower end of the bracket 8 and a nut 15a is screwed onto the nipple 15 for holding the bracket 8 and the header 13 tightly together.

Liquid is supplied to said header through a suitable conduit 19, which is preferably provided with a manually adjustable valve 20 and is suitably threaded onto the leftward end of the nipple 15.

i A flexible sheet 21, which is desirably also transparent, is gripped between a'pair of strips 22 and 23 and is held against the lower side of the header 13 by a series of screws of which one appears at 24. The curtain is advantageously made from any suitable transparent and flexible plastic, such as cellulose acetate, Mylar, etc., but it may be made of neoprene, or similar, within the purposes of the invention and within its advantages. Said curtain 21 extends across the full width of the belt 1 and preferably, as appearing in Figure 1, also extends a substantial distance beyond said belt on both sides thereof. Said curtain 21 extends downwardly a distance sufficient that it firmly lies against the upper surface of the workpiece W.

While the exact angle at which said discharge openings 16 discharge against said abrasive belt may be varied to suit varying conditions, it will normally be found preferable that said openings are arranged at not more than about 60 of angle with respect to the belt, and an angle of about 45 will be better if other conditions permit. With the axes of the discharge openings making with respect to the face of the belt an angle of between about 45 and about 60, the liquid discharged against said belt will lie on said belt without any material portion rebounding away therefrom and thus the maximum amount becomes available for cooling of the grinding surface as well as that portion of the workpiece immediately behind the surface being ground. Further, in this manner the control thereof is rendered most effective to minimize splashing of said liquid in the direction of the workman or onto the floor. At the same time, th e pressure at which the liquid is supplied to said openings should be of only moderate nature. More specifically, it should be enough to direct the entirety of the streams through the air layer travelling with the belt and thence to direct the streams against the belt, but small enough that there will be little tendency for liquid to rebound away from the belt. It will be recognized that the specific pressure will vary according to the size of the jet openings as compared with the volume of liquid supplied and accordingly the pressure selected for a given installation can be defined only in terms of pressure required to provide the performance above described.

Where a number of identical workpieces of a regular shape are being handled, it will be preferable to cut the lower edge of the curtain to match the shape of the workpiece so that one portion of the curtain will tit closely to the workpiece and other portions of the curtain will lie closely against the table. Inasmuch as very little of the liquid will splash onto the table when the workpiece is out of working position, the relatively small amount of liquid which may come through such cut-out portion when the workpiece is removed and before another workpiece is inserted, will be inconsequential.

Operation The device as described may be attached to practically any standard abrasive belt grinder merely by providing openings to receive the wing studs 11 and 12., together with providing a suitable connection for the conduit 19.

With the belt then running in a normal manner, an adequate supply of cutting and/or cooling liquid may be introduced from the conduit 19 into the bore 17 and thence by way of passageways 18 and 14 through the openings 16 against said belt. The curtain 21 will protect the workman from liquid splashing from the belt onto the table and thence back to the workman as well as from liquid being substantially peeled from the belt onto and by the workpiece and thence directed back against the workman. Thus, by protection of the workman in this manner, a much larger volume of cooling and/or cutting liquid may be used than would otherwise be possible and this permits a more rapid and cooler grinding operation than is possible in present practice.

Thus; actual tests have shown that with the much larger amount of cutting and/ or cooling liquid which it becomes possible to use by the device of the present invention, it is possible to hold a workpiece continuously against the belt for much longer periods of time than has been possible in previous practice without developing excessive heat therein, said excessive heat being undesirable both because of its unpleasant reaction on the operators hands and because of its destroying the otherwise carefully regulated and controlled crystalline structure of the material comprising the workpiece.

By causing the curtain 21 to be of highly flexible material, it will be recognized that said curtain will arrange itself firmly against a workpiece of any ordinary shape so that regardless of the size and shape of the workpiece, very little of the cooling and/ or cutting liquid will splash past the curtain onto the workman and this will be true both when the workpiece is forwardly against the abrasive belt in cutting position as well as when the workpiece is retracted either a limited distance or has been fully withdrawn from the machine.

It is recognized that there will be a slight inconvenience on the part of the workman in the initial stages of using this device by reason of the curtain 21 becoming covered with liquid and rendering it difficult for the workman to clearly see the Work. However, a properly directed light helps in this respect and most workmen will become accustomed to this in a short period of time and will be able to handle the apparatus satisfactory by combination of vision and feel and the majority of workmen will find the quality of the article produced, together with the convenience of being free from the splashing of the liquid being used for cooling and/or cutting purposes, far outweigh the disadvantages of somewhat limited visual control over the workpiece.

As a normal working operation progresses, the inevitable accumulation of debris in the liquid will eventually tend to obstruct some of the discharge openings 16. This cannot be tolerated to any great extent since it will destroy the purpose of the liquid dispensing apparatus. In the present construction, however, this situation is readily cured as it arises merely by removing the plug 14a and cleaning out the tube 14 with any convenient instrument, such as a cylindrically shaped brush.

While a specific embodiment of the invention has been utilized for illustrative purposes, it will be recognized that the invention may also be expressed in a variety of other specific embodiments and accordingly the hereinafter appended claims will be interpreted to cover such other embodiments unless said claims by their own terms expressly require otherwise.

I claim:

1. In a device for supplying cooling and/or cutting liquid to an abrasive belt and for simultaneously protecting the user from excessive splash of said liquid, the combination comprising: a conduit and means supporting same across and spaced from the face of said abrasive belt, a plurality of discharge openings through the side of said conduit opening in the general direction of the said abrasive belt; a work-supporting table adjacent said belt below said conduit; a flexible curtain extending from said conduit into close proximity with said table, said curtain being of width at least equal to that of the abrasive belt; means afiixing the upper edge of said curtain to said conduit, the remainder of said curtain being unsupported so that it hangs downwardly from said conduit and the lower end thereof is free to flex toward said belt whereby a workpiece may be pushed along said table under said curtain and said curtain will arrange itself sufliciently snugly against said workpiece that a minimum of liquid discharged from said conduit: will pass back either by traveling along said workpiece or by splashing against said table toward and against the operator.

2. An attachment for use with an abrasive belt machine having a work-supporting table, comprising in combination: a header containing a conduit extending substantially the full length thereof and having a plurality of discharge openings through the side thereof; a bracket for supporting said header in a selected position on said machine and with the outlet ends of said discharge openings arranged in a line parallel with and spaced from the working surface of the abrasive belt; a flexible and transparent curtain and clamp means aflixing the upper edge of said curtain onto said header, the remainder of said curtain being unsupported so that it may hang downwardly from said header to a location adjacent the upper surface of said table but spaced therefrom a distance not greater than the vertical dimension of the workpiece, the lower end of said curtain being free toflex whereby a workpiece may be pushed under said curtain and in contract therewith into contact with said abrasive belt.

3. The device defined in claim 2 wherein said discharge openings are directed at an angle of not more than about 60 with respect to the surface of said belt.

4. The device defined in claim 2 wherein the lower edge of the curtain is cut to match and fit snugly around the upper and side surfaces of the workpiece.

5. A grinding machine comprising a substantially vertically arranged, movable abrasive belt; a work support located adjacent a course of said belt; a conduit mounted above said work support for directing liquid against said course of said belt; a flexible sheet supported along the upper end thereof adjacent said conduit and extending downwardly substantially to said work support in front of said course of said belt, the lower end of said sheet being free to flex toward said belt whereby a workpiece supported on said work support may be moved into engagement with said course of said belt and the lower end of said sheet will flex to the extent required to permit such movement, said sheet serving as a splash shield to confine the liquid in the zone between said course of said belt and said sheet.

References Cited in the file of this patent UNITED STATES PATENTS 986,170 Heady Mar. 7, 1911 2,228,386 Burns Jan. 14, 1941 2,292,229 Krueger Aug. 4, 1942 2,550,899 Zsamboky May 1, 1951 2,562,229 Bell Ju'y 31, 1951 2,757,487 Coburn Aug. 7, 1956

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