US2413880A - Machine for forming spherical bodies - Google Patents

Description

Jan. 7, 1947. A. c. MASON MACHINE FOR FORMING SPHERICAL BODIES Fil'ed May '22, '1943 2 Sheets-Sheet 1 ATTORNEY.

Jari. 7, 1947. MASO 2,413,880

MACHINE FOR FORMING SPHERIC AL B ODIES Filed May 22, 1943 2 Sheets-Sheet 2 INVENTOR, #rfl'ua Eli/4.50 g km ATTORNEY.

Patented Jan. 7, 1947 uuirao ,s'ra'rs PATENT orr ca,

' 2,413,880 MACmNE FOR FORMING SPHERICAL BQDIES Arthur 0. Mason, Paterson, N. J. Application May 22, 1943, Serial No. 487,985

This invention relates to gr n machines a;

the grinding element, the other rotary element acting as what is usually termed a feed-wheel or as means to rotatethe work so that the grinding, shall proceed circumferentially thereof.

. Inthe use of such a machine as heretofore known the'production of an article approaching true sphericity has been impossible whether the work was a stick to be developed into a plurality of articles or an individual piece of a length more or less approximating the diameter of the ultimate article. Assuming the grinding element to be formed with a cross-sectionally semi-circular grinding groove, in either case account has to be taken of two tactors: that the grinding must terminate with clearance between the two elements, which means that polar projections will be left on the article if the work was initially wider than the groove; and that, though the grinding element be formed with its groove perfectly arcuate or even truly semi-circular in cross-section, the

general shape of the product will inevitably be more or less oval or elliptical in lengthwise section.

As indicated, the three controlling parts are the two rotary elements, with their axes approximately though not necessarily geometrically parallel, and the anvil. I have found that if the feed-wheel or work-rotating element provides a contact surface for the piece or work which extends approximately straight and is pitched or inclined away from what I shall hereinafter define as the normal axis of the work and relativelyv to the contact surfaces provided by the other two parts and if one of the three parts or some other.

medium of the equipment provides an abutment constantly serving during the grinding to oppose displacement of the work. laterally, or crosswise of the contact surfaces of said elements (i. e.,

lengthwise of said axis) while the grinding is proceeding, the work becomes subject to forces .which act to rotate it. universally, or no longer and cemented to that of the other so that the lapping zone of the two marginal portions exists without cross-sectional curvature and hence with such a flat. The aforesaid normal axis is herein taken to be that axis which, the axes of the grinding and feed-wheel elements being as stated at least approximately parallel, is substantially parallel with both such axes.

In the drawings, Fig. 1 shows the grinding and feed-wheel eie-' 'ments in horizontal section and the anvil in plan,

the feed-wheel element having the incline;

Fig. 2 is a plan view of the machine embodyin the construction of Fig. 1;

' tional machine in which I is the frame; it the grind-wheel or grinding element iournaled on a fixed axis in the frame and here having a plurality of circumferential abrasive grooves its which are cross-sectionally at least arouate or actually substantially semi-circular as an incident of the form and relation of the alternating flutes or ribs iBbi iii a cylindrical feed-wheel or work-rotating element journaled in an upstanding carrier-l pivoted in the frame; and there is means as follows to rotate the two elements and simultaneously move the element It, whose axis is here parallel with that of element it, toward the latter: 3A pulley 5 through a belt d drives a pulley member I, and this member through a belt 8 drives a pulley 9 fast to element it; pulley 5 through a belt it! drives element it; and element it through worm-and-worm-wheel gearing i i rotates a cam l2 revoluble in carrier 83 and havin its cam surface abutting a plunger it in the frame assumed to be urged by a spring (not shown) toward the cam. The work or piece, being more or less round and having at best but approximate spherlcity, is of such form as to enter any groove its as far as substantially the complete depth of the groove will permit and when so positioned it is to be subjected to pressure by the two ele-' ments I6 and it! while the latter are rotated in the direction of the arrows in Fig. 3, element it toeffect the grinding or attrition and element It so as controllably to rotate the work and thus cause the grinding to proceed circumferentially thereof. (The present equipment is designed, as

. shown, for grinding a number of pieces simultaneously) To support the work against the impolling effort of the grinding element there is the anvil l1 formed as a bar extending horizontally between the two elements, its top work-supporting surface being preferably as usual generally beveled upwardly from its face adjoining element I8 to its opposite face and cutting the horizontal plane common to the axes of said elements. At Ha. upright grooves are as usual formed in the anvil to accommodate the flutes of element I8, providing between them tongues 11b for supporting the work as it becomes more and more ground away. The features of the anvil thus described are conventional.

According to this invention the work-rotating element l8 has its work-contact surface at Ma,

formed circumferentially thereof, inclined or pitched from the mentioned normal axis, here in zones opposed to the respective grooves lie of the grinding element since the present equipment is designed for grinding a number of pieces simulrotated in response to the rotary effort of ele-.

merit l8. But whereas, without the mentioned incline IBa, the work would be constantly rotated around its said normal axis (wherefore the'grinding would be confined to a central zone perpendicular to said axis, thus ultimately to develop the work more or less elongated, as elliptical), the work undergoes universal rotation and hence becomes spherically formed. This is evidently because, due to the incline, the points of contact (1 and z in Fig. 1) of the two rotary elements with the work are not in a common plane cutting the work centrally and perpendicular to said normal axis. The work of course meanwhile tends to shift lengthwise of said axis, here to the right in Fig. 1, but such displacement is opposed by an abutment afforded by a part of the equipment or machine, here by a flute of element l 8 and so that such displacement occurs only at the rate at which the work is ground away. I

It is to be understood that in Fig. 1 the showing is schematic for the purpose of illustrating why the universal movement of the work is made to occur. It is not to be assumed that in all cases, regardless, for instance, of the material of which the work is formed, the work would have the relatively limited diameter there shown. Thus in practice, where the work was composed of a hard plastic material, for instance, perhaps approaching butv lacking substantially true sphericity, it has been introduced to the groove of the grinding element having such a slightly excessive diameter that it would fail to contact the groove at the deepest part of such groove. In the operation in that case the work at first is made to undergo rotation around its said normal axis, that is, until it is ground away by said element sufllciently to enter the groove completely, but once this has been accomplished,

whereas in the absence of my invention thev grinding would cause the work to be developed elliptical in form, in accordance with my invention universal rotation sets in and the work is developed spherical.

Having thus fully described my invention, what I claim is: v

1. An equipment for grinding work spherically including a rotary grinding element having a circumferential abrasive work contact-surface, a

rotary work-rotating element having a circumferential work contact-surface, one of said elements being movable toward theother, an anvil arranged between said elements and having a work contact-surface arranged to support the work against the impelling effort of the grinding element, structure in which said elements are journaled with their axes of rotation at least approximating parallelism with each other and their contact-surfaces opposed to each other and by which structure said anvil is supported, and means to rotate said elements, said work-rotating element having its contact-surface extending approximately straight and inclined from the normal axis of the work and relatively to the other two contact surfaces and said equipment providing an abutment constantly opposing displacement of the work crosswise of the contactsurfaces of said elements.

2. The equipment set forth in claim 1 characterized by one of the three parts formed by said elements and anvil providing said abutment. ARTHUR C. MASON.

Images