US2911767A - Grinding machine - Google Patents

Description

Nov. 10, 1959 Filed Feb. 25, 1958 H. SIELEMANN GRINDING MACHINE S Sheets-Sheet 1 AGENT Nov. 10, 1959 H. SIELEMANN GRINDING MACHINE 3 Sheets-Sheet 2 Filed Feb. 25. 1958 [IA/V8 s/ELENA/V/V By M PM,

7 AGENT Nov. 10, 1959 H. SIELEMANN GRINDING MACHINE 3 Sheets-Sheet 3 Filed Feb. 25, 1958 Y x "M" N I. m l

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United States Patent i GRINDING MACHINE Hans Sielemann, Bunde, Westphalia, Germany Application February 25, 1958, Serial No. 717,400

7 Claims. ((31. "SI- 166) The present invention relates to a one-column grinding machine with a circular or surface grinding table.

It is an object of the present invention to provide a one-column grinding machine wherein said column consists of a cylindrical inner column and an outer column surrounding the same in which the outer column has an equilateral polygonal cross section and each outer surface of the outer column carries a headstock of a grinding spindle so as to be movable in a vertical direction relative to the columns independently of the other headstocks, and wherein each grinding spindle is designed and equipped for a different grinding operation.

For attaining this object the outer column of a grinding machine according to a preferred embodiment of the invention is made of a substantially triangular cross section, and each of the three outer surfaces of such a column is provided with a separate headstock which is movable in a vertical direction relative to the column, and one grinding spindle is designed to be used for face grinding, another spindle for internal circular grinding, and the third for external circular grinding. v

Another important feature of the invention resides in the fact that a stationary piston rod extends through the piston of the elevating mechanism at the upper end of the inner column, and that fluid conduits extend through such stationary piston rod and then through suitable connecting elements within a gear housing above the outer column which are adapted to swivel with the outer column about the vertical axis of the latter for supplying a hydraulic pressure fluid to individual hydraulic motors to permit each grinding spindle to he movable upwardly and downwardly in a vertical direction independently of the other spindles.

A further object of the present invention is to provide hydraulically operated means for insuring that during the grinding operation of the machine the outer column will be securely and rigidly connected to the inner column by hydraulically pressing the outer column upon conical seats which are provided on or secured to the inner I column in a vertically spaced relation to each other.

Further objects, features, and advantagestof the pres-v ent invention will be apparent from the following detailed description thereof, particularly when read with reference to the accompanying drawings, in which:

Fig. 1 shows a plan view of a preferred embodiment of the machine according to the invention;

Fig. 2 shows a horizontal cross section of the inner and outer columns taken along lines A--B of Fig. 3; while Fig. 3 shows a vertical cross section of the column taken along line A--BC of Fig. 2.

Referring to the drawings, the lower frame of the machine is provided in the conventional manner with a sliding carriage 2 which is movable in the direction of arrow A- and carries, for example, a conventional circular grinding table 3. Since this circular grinding table may also be replaced by a conventional face grinding table which would then be movable in a direction vertical to 2 the plane of Fig. 1, it is only indicated diagrammatically therein.

The lower frame 1 of the machine further carries a circular base member 4 with a conical outer surface 4a thereon. Base member 4, in turn, carries an inner cylindrical column 5, the upper end of which is recessed to have a ring 5a fitted thereon which likewise has a conical outer surface. The inner cylindrical column 5 is surrounded by an outer column 6 which, however, has a polygonal cross-sectional shape and may, for example, be in' general of a substantially triangular configuration, as illustrated in the drawings. At its lower and upper ends, the outer column 6 carries inner rings 6b and 6c with inner conical surfaces which engage with and rest upon the outer conical surfaces of basemember 4 and ring 5a, respectively. The spaced arrangement of the two pairs of conical surfaces atth'e upper and lower ends of columns 5 and 6 insures during the operation of the machine that the outer column 6 willbe absolutely rigidly mounted on the stationary inner column 5. The upper end of column 6 further carries a cover defining a housing 7 for enclosing the gears or hydraulic lines for driving the headstocks of the grinding spindles.

In the particular embodiment of the invention as illustrated in the drawings, three spindle headstocks are mounted on the outer surfaces of the outer column 6 so as to be slidable in a vertical direction. Headstock 8 may be used for internal circular grinding, headstock 9 for external circular grinding, and headstock 10 for face grinding. Each grinding spindle is rotatable about a vertical axis. The three headstocks 8, 9, and 10 are guided independently of each other in a vertical direction on slide bars 8a, 9a, and 1%, respectively, and each headstock is provided with a separate drive mechanism, not shown, for moving it upwardly and downwardly in a vertical direction independently of the other headstocks and relative to the outer column 6. Such movement'may, for example, be produced by hydraulically operated motors which are disposed at the inside of column 6 and are secured thereto. The hydraulic conduits 12 and 13 lead ing to these motors may then extend through the stationary piston rod 11 at the center of the upper end of the inner column 5, while within housing 7 suitable cou-- pling elements are provided through which conduits 12 and 13 are connected with conduits 14 which are secured to the outer column 6 and lead to the hydraulic motors within this column.

The swiveling adjustment of the outer column 6 with the headstocks of the grinding spindles thereon proceeds in the following manner: 1

When the machine is started, it also starts the operation of a hydraulic pump which, after a suitable valve has been opened, pumps the pressure fluid through conduit 21 into a hydraulic cylinder 22 so that a piston 22a therein, through a thrust bearing 23, will lift the entire outer column 6 including the gear housing 7 thereon to such an extent that the inner conical surfaces on rings 6b and 60 will be separated from the corresponding outer conical surfaces on members 4a and 5a. The pressure which is exerted by the hydraulic fluid upon piston 12a then holds the outer column 6 in a suspended position so as to permit it to be swiveled about a vertical axis either manually or by any suitable mechanical'means until the headstock which is next intendedto be used in the grinding operation will be in the proper position above the grinding table 3.

'If the pressure in cylinder 22 is then release-d, the outer column 6 will again be lowered until its conical seats 6b and 6c are firmly settled on the corresponding seats 4a and 5a on the inner column 5. Since these seats are provided at the upper and lower ends of the stationary column 5 and have a diameter of aconsiderable size at Patented Nov. 10, 1959.

least at the lower end, the outer column 6 will always be very rigidly mounted when in the operating or grinding position, and such firm mounting may be repeated indefinitely since the only result of any wear upon the corresponding conical seats 4a, 6b and 5a, 6c which might possible occur after the machine has been inoperatiofi for a very long time will be that the entire outer column when lowered will settle at a slightly lower point.

This, however, will not affect the rigidity and angular accuracy of the adjustment of the machine.

In order to insure that the outer column when lowered will always be rigidly mounted on the conical seats and that any undesired shifting movements during the grinding operation will be prevented, the present invention further provides hydraulic means for pressing the outer column firmly upon the conical seats on the inner column. This may be attained, for example, by providing several hydraulic cylinders 24 at different points within the lower part of the inner column 5. The piston rods 24a of these cylinders act upon two-armed levers 25 which are pivotably mounted at 26 on weblike ribs 27 on the outer peripheral surface of the inner column 5. Cylinders 24 are connected through pressure conduits 28 with the hydraulic system of the machine so that, when the pressure isreleased from cylinder 22 to permit the outer column 6 to return to its rest position, cylinders 24 will at the same time be placed under pressure through conduits 28. The pistons in cylinders 24 and piston rods 24a thereon will then move upwardly and pivotlevers 25 about their axes 26 so that the downwardly projecting ends 25a thereof will press upon an inwardly projecting shoulder on the outer column 6 and thereby press the conical seats 6b and 60 on the outer column firmly upon the corresponding seats 4a and 5a on the inner column 5. The pressure within cylinders 24 is preferably maintained until it is again necessary to lift the outer column for the purpose of swiveling the same about its vertical axis. The control valves, not shown, should then be adjusted so that the pressure in cylinders 24 will be released and be newly supplied to cylinder 22 to lift the outer column 6 for the next swiveling operation. 4

The vertical adjustment of the headstocks 8, 9, and which are slidably mounted on the outer column 6 may be carried out in the conventional manner, for example, mechanically by means of gears or, as previously described, by means of hydraulic motors which are supplied with hydraulic pressure fluid through conduits 14. In this connection, insofar as the present invention is concerned, it is merely essential that the headstocks of the grinding spindles will be movable independently of each other so that only that headstock will be moved which is in the operating position, while the other headstocks remain unaffected. The particular control and driving elements which are required to produce this result may be of any suitable design known in the art and do not constitute a part of this invention.

Because of its very simple and sturdy construction the machine has a practically unsurpassable rigidity, and the results of the grinding operations carried out thereon are of the highest quality and accuracy. By providing this machine in accordance with the invention with three or more headstocks, all the necessary grinding operations including external and internal circular grinding and face grinding of a workpiece may be carried out without requiring any reclamping thereof. In place of one or more headstocks, the machine may also be provided at one or more work stations of the outer column with suitable tools for microfinishing the respective workpiece so that the entire production program may be carried out automatically. Another very important advantage of the new machine is that by making the grinding table.

pivotable at an angle of, for example, 10 in both directions, the versatility of the machine may be considerably increased. If such a machine is to be used in a production line the independent movability of the grinding spindles even permits each headstock to be provided with a separate grinding table so that all the grinding spindles may be used simultaneously to carry out similar or different grinding operations on several workpieces at the same time. In such an event, it is advisable to provide a suitable indexing mechanism of a type known as such on base 4 of the inner column 5 for locking the outer column 6 after each swiveling movement thereof in its new angular position.

Although my invention has been illustrated and described with reference to the preferred embodiments thereof, I wish to have it understood that it is in no way limited to the details of such embodiments, but is capable of numerous modifications within the scope of the appended claims.

Having thus fully disclosed my invention, what I claim 1. A grinding machine comprising, in combination: a frame, grinding table on said frame, a first inner column rigidly secured to said frame, two vertically spaced conical seats fixedly mounted on said inner column, a second outer column surrounding the inner column, two vertically spaced conicalbearing elements fixedly mounted in the interior of the outer column and facing the conical seats on the inner column, the tapers of each conical seat and the conical bearing element facing 'it being substantially identical, whereby the inner and outer columns are frictionally coupled upon engagement of the seats with their respective conicalbearing elements and the outer column is free to swivel about the inner column upon disengagement of the conical bearing elements from their respective conical seats, fluid pressure means for lifting the outer column and thus to disengage the conical bearing elements from the conical seats, a plurality of headstocks, a grinding spindle rotatably mounted in each headstock, and independent bearing means for each headstock and slidably mounting each headstock on the outer column for movement in a vertical direction relative .to said outer column.

2. The grinding machine of claim 1, wherein the outer column has a polygonal periphery and one headstock is mounted on each side of the outer column.

3. The grinding machine of claim 1, comprising fluid pressure-operated means actuatable to exert downward pressure upon the outer column and thus to press the conical bearing elements against the conical seats.

4. A grinding machine comprising, in combination: a frame, a grinding table on said frame, a hollow inner column rigidly secured to said frame, two vertically spaced conical seats fixedly mounted on said hollow inner column, a hollow outer column surrounding the inner column and being coaxial therewith, two vertically spaced conical bearing elements fixedly mounted in the interior of the hollow outer column and facing respective ones of said conical seats on the hollow inner column, whereby the inner and outer hollow columns are frictionally coupled upon engagement of the conical seats with their respective conical bearing elements and the outer column is free to swivel about the inner column upon disengagement of the conical bearing elements from their respective conical seats, a central bearing member coaxially mounted in said hollow inner column, fluid pressure means ineluding a vertically movable piston in said central bearing member, a web fixedly connected to said outer column and vertically movably by said piston, fluid pressure applied upon said piston moving the piston, the web, and the outer column connected thereto vertically upwardly to disengage the conical bearing elements from the conical seats and to permit the outer column to swivel freely upon said central bearing member, a plurality of head stocks, a grinding spindle rotatably mounted in each headstock, and independent bearing means for each headstock and slidably mounting each headstock on the outer column for movement in a vertical direction relative to said outer column.

5. The grinding machine of claim 4, wherein said central bearing member is a hydraulic cylinder carrying said movable piston and a thrust bearing means is mounted between the piston and the web whereby the web and the outer column may be swiveled on said thrust bearing means.

6. The grinding machine of claim 4, comprising fluid pressure means for slidably moving each headstock, the fluid pressure means including fluid conduit means leading through said central bearing member.

7. The grinding machine of claim 4, comprising fluid References Cited in the file of this patent UNITED STATES PATENTS Pfauter Apr. 25, 1939 Bruet et al Nov. 21, 1950 FOREIGN PATENTS Germany Apr. 17, 1942

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