US1909110A - Building up of machine tools, specially grinding machines - Google Patents

Description

May 16, 1933. c. KRUG 1,909,110

BUILDING UP OF MACHINE TOOLS, SPECIALLY GRINDING MACHINES Filed Oct. 29, 1928 :s Sheets-Sheet .1

1- I O a 0 47 44\== h 15 g 42 46 46%- May 16, 1933. c. KRUG BUILDING UP OF MACHINE TOOLS, SPECIALLY GRINDING MACHINES Filed Oct. 29. 1928 s Sheets-Sheet 2 May 16, 1933. c KRUG 1,909,110

BUILDING UP OF MACHINE TOOLS, SPECIALLI GRINDING MACHINES Filed Oct. 29, 1928 3 Sheets-Sheet 3 Patented May 16, 1933 UNITED STATES CARL KRU'G, OF FRANKFORT-ON-THE-MAIN, GERMANY BUILDING U]? OF MACHINE Toots, SPECIALLY GRINDING MACHINES Application filed October 29, 1928, Serial No. 315,902, and in Germany October 26, 1927.

The main building elements of machine tools, as foundations, frames, under frames, standards, uprights, arms, tables or the like, are preferably cast of iron. The quantity of material used for this purpose is quite out of proportion to what would be necessary on account of the stresses to which these elements are submitted or of the admissible alteration of shape. Foundry technical reasons and the consideration of the treatment make it generally necessary to increase to a multiple the quantity of material which would be absolutely necessary for fulfilling the technical purpose of the machine tool.

The reason for the almost exclusive use of cast iron is the simplicity with which by the casting process even the most complicated forms can be obtained.

By the modern development of the weldingtechnics the possibility of using building materials possessing higher resistance and which are not moulded by casting process h s been thoroughly altered.

'This invention has for its object to do away with the utilization of cast iron preferably in order to reduce the cost of manufacture of the machines and to improve the machines with the aid of the welding technics which have only quite recently de 0 veloped to perfectness and economy. It has already been proposed to build certain parts of driving engines, like casings of dynamos or foundation frames for the same from ingot steel sheets, but it has never been proposed to intentionally transform the existing types of machine tools so that it becomes possible and remunerative to use building.

bodies of steel for the several elements. One has, of course, to count with the increased expenses for the welding but these expenses are more than compensated b savings in expenses. for transport, simpli ed working, suppression of the expenses for models, cheaper machines and serious reduction of storing expenses and general expenses, not to mention the advantage of being no longer .dependent on the foundries and the saving of time as no models have to be made. It is however impossible to substitute simply wrought iron and ingot steel for the cast iron and to merely alter the cross sections in .the relation 1 by 2, 5, i. e. in the proportion of the modulus of elasticity of these materials. The use of wrought iron and steel and the utilization of the welding technics require new peculiar forms. Specially disappear the gradual transitions at alterations of cross section peculiar to the casting process and the local accumulations of material, and in general all expenditures in material which are not absolutely required by the absolutely necessary degree of resistance and limitation of alteration of shape. A principal difficulty is the mounting of guide faces for moving machine elements. This difiiculty is overcome according to the invention in that the connection elements with guide faces in completely finished state are detachably, adjustably and readjustably connected, with interposition of an intermed-- iate element distributing and transmitting pressure, to the hollow or frame bodies made of wrought iron, ingot iron or ingot steel sheet plates or webs by means of weld ings. This requires the solution of several secondary problems for the machine elements with plane guide faces. These problems are evidently other than for elements which possess rounded guide faces, like round bearings, bushes or the like. Building elements with simple fitted block-sup porting-or carrying surfaces are also joined in completely finished state, the adjustability and re-adjustability being however generally omitted, v

It might be apprehended that the natu-- ral vibrations of the frames and of their elements, which are specially dreaded in the building of grinding machines, could not be securely avoided whenthese frames and 9 I their elements are made ofthin rolled sheet metal plates. Calculation shows however that in preserving the same rigidity the natural vibration coeflicients remain the same. As with a very little consumption of 5 material the natural vibration coefiicients can be takenconsiderably higher by increasing the degree of compactness of the several building elements, for instance'by insertion of intermediate transverse bars, the new manner of building produces considerably greater rigidity and resistance against pre3- udicial vibrations than hitherto.

The advantages of the new building meth- 5 0d are considerable: extraordinary savings in wa es, in expenses for material and power, lig t machines and consequently low cost for transport and little loading of ceilings, greater rigidity and resistance against vibrations, little losses from friction and power in the moved building elements, possibility of carrying out more rapidly, andshorter terms for delivery, cheaper machine installations, less space required for the manufacturing, suppression of the inaccuracies and of the re-fashioning owing to warping at the ageing of the cast, suppression of expensive models, of the expenses for storing, and of the high insurance premiums due to the liability of the models to catch fire, less expensive maintainance, possibilities to rap idly alter the shape, greater security against breaking in transport, unsensitiveness against rough treatment, greater accuracy in the long run, owing to the re-a-djustability of the guide faces, simplest possibility of using the most favorable material pair: steel and cast iron for guide faces, possibility of building experimental machines and special machines in the shortest delay Without loss of time and without manufacturing of expensive models which, if not satisfactory, are without value, possibility of using standard building elements like track plates, webs, arllxgle pieces, sliding face elements or the li e.

For grinding machines the new building manner is especially advisable for the reason that the warping of the cast pieces owing to ageing is very prejudicial to the high degrees of accuracy of the grinding machines at the construction of the same as well as in service. The possibility of readjusting the guide faces is of decisive importance for the preservation of the initial high degree of accuracy of the machines, and it is especially important for eventual breaking of the grinding tools that brittle materials like cast iron be avoided. Just in the grinding machines the disparity between the actual consumption of material and that which would be necessary to fulfill the technical purpose, is very conspicuous. One needs only compare the dimensions of the small grinding wheels with the disproportionate shape of the whole machine.

This is why a machine tool of the class of grinding machines has been selected as example of the application of the invention.

In the accompanying drawings a surface grinding machine of the form of construction which has become known by the main German Patent No. 399,144 is shown in the 65 Figs. 1 to 10.

screw connections.

Fig. 1 is a front elevation showing the grinding machine.

Fig. 2 is a section through the machine.

Fig. 3 shows in elevation partly in section the underframe for the grinding wheel spindle head stock.

Fig. 4 shows in section the bed and the table.

Figs. 5, 6 and 7 illustrate how building eliements with plane guide faces are mounte Figs. 8 and 9 illustrate the mounting of a building element with round guide surface, i. e. the bearing for the grinding wheel spindle shaft.

In Figs. 1 and 2, 1 designates the slide with the grinding wheel spindle 2, which carries the main driving-disc 3, the driving disc 4 for the pump and the grinding tool 5.

The slide 1 for the grinding wheel spindle is shiftably arranged on the underframe 6 and the table 7 is shiftably arranged on the bed 8, the underframe and bed having on the walls facing each other projections 9 ending in parallel vertical planes and adapted to be connected with each other by Between them a clamping and adjusting device 10 is arranged enabling the spacing of the free ends of the uprights. The table 7 is connected with a piston movable in a cylinder 11 'fixed on the bed 8. In this cylinder end the conduits 12 and 13 for the pressure oil flowing in and out, the regulating of which is eifected by the piston slide 14 to which the pressure oil is supplied by a pfessure pump arranged in the machine. The grinding wheel spindle slide 1 and the corresponding underframe 6, the table 7 and the bed 8 are four main building elements of complicated shape, which hitherto have been made of cast iron. According to theinvention they are composed of correspondingly cut plates of wrought iron or ingot steel and connected with each other by welding, so that preponderantly hollow bodies or cells are produced which are preferably limited by right angles. The hollow bodies are stayed in the interior by horizontal and vertical partitions, supporting angle irons, webs and the like, which are connected with the main body by welding. In the figures the outer plates 15 are united with the inner plates 16, which may be of different shapes and dimensions, to form hollow bodies or cells. It is also possible that an inner plate extends through the outer plates and becomes itself an outer plate 17. The connection of the several plates is effected by butt welding, by overlapping or by attaching by means of several welding points, according to requirement .and accessibility of the welding points. For connecting two plates a third element, for instance an angle iron 18, may be. used, which is connected with the two plates by welding.

justed and re-adjusted. Figs. 5 and 6 illustratc in elevation and section details of the point at which the guide rod is connected to the main body.

In building elements, which serve exclusively for a fitting, the re-adjusting device may be suppressed, so that the finished fitted block is connected to the main body merely by fixation screws, eventually with the aid of intermediate elements. Under circumstances a readjusting device may be preferably provided. This will be the case if the mutual position of two main building elements, for instance of the underframes 6 and of the bed 8, has to be corrected (Fig. 3

In Figs. 8 and 9 is 2 the grinding wheel spindle with its bearing, which consists of a roller bearing 27 and a double thrust bearing 28 mounted in the common casing 29. This casing 29 is sunk in the bearing head 30 of the machine, which consists of wrought iron or steel sheet plates 16 cut accordingly and welded together, and it is fixed in the casing by means of screws 31 and pressure elements 32. The shafts of the screws 31 move with clearance in the corresponding holes of the bearing head so that the casing together with the shajft can be adjusted parallel to the axis of the grinding wheel spindle by little amounts required for the adjusting and then secured in the adjusted position. In the flange of the bearing casing a set of adjusting screws 33 is further arranged, by which the angle to the axis of the grinding wheel spindle and to the axis of the bearing head may be altered by little amounts necessary for the adjusting.

-I claim 1. As an article of manufacture a frame of grinding machines built up of a multiplicity of cells formed of rolled sheet metal and welded together preferably by spot welding in combination with machine tool slide ways having fitted and guide faces joined to the frame in finished state in order to improve the possibility of working.

2. As an article of manufacture a frame of grinding machines built up of a multiplicity of cells formed of rolled sheet metal and welded together preferably by spot welding in combination with machine tool slide ways having fitted and guide faces joined adjustabl and re-adjustably to the frame in finishe state.

3. As an article of manufacture a. frame of grinding machines built up of a multiplicity of cells the walls of which are erected of rolled thin sheet metal not exceeding 5 mms in thickness and preferably welded together by spot welding in order to obtain the highest possible rigidity with the minimum amount of material.

4. As an article of manufacture, a frame of grinding machines built up exclusively of thin sheet metal plates of equal thickness throughout, forming a multiplicity of cells welded together by s ot-welding.

In testimony whereof I a x my signature.

' CARL KRUG.

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