US2386742A

US2386742A - Grinding machine

Info

Publication number: US2386742A
Application number: US570710A
Authority: US
Inventors: Arden B Macneill
Original assignee: Individual
Current assignee: Individual
Priority date: 1944-12-30
Filing date: 1944-12-30
Publication date: 1945-10-09
Anticipated expiration: 1962-10-09

Description

Oct. 9, 1945. B, MacNElLL 2,386,742

GRINDING MACHINE Filed Dec. 30, 1944' 5 Sheets-Sheet i Iawenor Oct. 9, 1945. MaCNEILL GRINDING MACHINE Fi led Dec. so, 1944 5 Sheets-Sheet s flii'owneya Patented Oct. 9, 1945 UNITED STATES PATENT OFFICE GRINDING MACHINE Arden B. MacNeill, Waltham, Mass.

Application December 30, 1944, Serial No. 570,710

2 Claims.

This invention relates to grinders for accurately grinding to extremely close tolerances the exposed ends of tubular blanks or other work pieces. These work pieces are usually of small size and have to be finished in large quantities and at low cost, and accordingly the main object of my invention is to provide an efiicient and reliable machine of compact size and simple design for performing this work. Other objects and advantages will appear as this description proceeds.

In a preferred embodiment of my invention, my machine comprises a horizontally disposed rotatable feed wheel having about its periphery a plurality of spaced vertically disposed notches constituting work-holding pockets. Each pocket is preferably of a size to snugly receive a single work piece placed endwise therein and of a depth slightly less than the length of the work piece so that the upper endsof the work pieces project slightly beyond the upper face of the feed wheel.

The feed wheel is constantly rotated in the same direction about a vertical axis to successively present the exposed ends of the work pieces held within said pockets to a pair of spaced overhead grinding wheels which are constantly rotated about axes at right angles to the axis of rotation of the feed wheel.

Preferably the grinding wheels are disposedopposite to each other at either side of the feed wheel shaft so as successively to act upon the exposed ends of the work pieces as the rotation of the feed wheel carries them beneath each grinding wheel.

Preferably also, the first grinding wheel to contact the work pieces is set to rough grind from the work pieces substantially all of the material thereof projecting beyond the upper face of the work wheel. The second grinding wheel finishes the work pieces totheir final dimensions when said pieces in the continued rotation of the feed wheel are carried from beneath the first grinding wheel to beneath said second grinding wheel.

The work pieces are ready to be ejected from the pockets of the feed wheel one at a time and discharged from the machine, such discharge occurring at a later point in the cycle of the feed wheel.

Suitable mechanism is provided for positively confining the work pieces in the holding pockets of the feed wheel while in orbit and until ready to be discharged, and also for exerting additional confining pressure upon the work pieces when they reach the points in their orbit at which their projecting upper ends are contacted by the respective grinding wheels.

The operation of my machine is practically automatic. The workman needs only to keep the pockets of the feed wheel filled with work pieces, since the continuous rotation of the feed wheel successively carries the work pieces from one grinding wheel to the other and finally to their discharge point.

An illustrative embodiment of my machine is shown in the accompanying drawings, wherein:

Fig. l is a horizontal plan section of my machine.

Fig. 2 is a front elevation, partly broken away.

Fig. 3 is an enlarged top plan view of the feed wheel and associated parts, and

Fig. 4 is a section on the line !I4, of Fig. 3.

My machine comprises a frame I0 on which is horizontally supported a central base II and a trough I2. The base I I supports my novel feed wheel. .The trough I2 establishes a reservoir for the coolant for the grinding wheels.

My feed wheel includes a stationary lower member I3 resting on base II and a superposed revolving upper member I4. Surrounding said members is a segmental ring I5 which is fixed to the frame and is of a height substantially equal to the combined thickness of said members. Ring I5 is peripherally cut away as at A, B and C (see Fig. 3) for a purpose .to be later explained.

Revolving member I4 is provided at its periphery with a plurality of spaced notches I'I constituting vertically disposed work-holding pockets for the work pieces W, the bottoms of said pockets being furnished by the underlying stationary member I3. The notches I! are preferably of V-shape with their wide ends opening out to the perimeter of member I4.

The work pieces or blanks may be tubular, as shown, and are inserted endwise one in each pocket H. In length, they slightly exceed the depth of the pockets, so that their upper ends project slightly above the upper face of member I4, as indicated in dotted lines at the right in Fig. 4. The distance that. the upper ends of the work pieces project beyond the upper face of member I4 may correspond approximately to the amount of material to be removed therefrom by the grinding wheels.

The work pieces are held within the pockets, until ready to be discharged, by means of a band spring I8 extending around the perimeter of the revolving member I4 from anchor point I9 to anchor point 20 on member I5 (see Fig. 3).

Member I4 is driven as follows. Both it, member I3, and base I! are drilled to receive a stud shaft 2| which is flanged as at 22 and fastened as at 23 to member I4 (see Fig. 4). The-fit of stud shaft 2I in parts I3 and II is tight enough to overcome any tendency towards wobbling but not tight enough to impart rotation to said parts. The upper end of stud shaft 2| is bored as at 24 and cross-slotted as at 25 to receive. respectively, the lower end of drive shaft 26 and fastening pin 21. This form of driving connection permits wheels of different thickness to be interchangeably used in the machine.

Drive shaft 26 is journaled at its upper end in any suitable bearing 28 (see Fig. 2) and is constantly driven from any suitable power source, as the shaft 42 through

gears

29 and 29 on shafts 26 and 42, respectively. In order that a feed wheel may be readily disconnected from the shaft 26 to permit its replacement the drive shaft 26 may conveniently be slidably journaled in the bearing 28 to permit the shaft to be raised from engagement with the stud shaft 2!.

Rising from the frame [0. is a plurality of spaced brackets 30 providing alined bearings 3! for a pair of spaced alined horizontally disposed

grinding wheel shafts

32, 33 disposed one on each side of the feed wheel shaft 25 and each carrying at its inner end a grinding

wheel

34, 35.

Shafts

32, 33 are constantly driven from any suitable driving source. As here shown, the

' driving connections comprise

pulleys

36, 31 on said

shafts

32, 33 and

belts

38, 39 trained over said pulleys and over other pulleys 40 and 4| on shaft 42 which shaft thus drives both the feed wheel shaft 26 and the pair of grinding

Wheel shafts

32, 33.

In order to insure that the Work pieces Will be tightly held against movement in their pockets while the grinding wheels are at work, I arrange in the cut-outs B and C spring-tensioned

pressure shoes

43, 44. The faces of said shoes bear against the band spring l8 at said cutouts and force it inwardly into tight clamping engagement with the work pieces, the shoe faces being preferably curved to conform to the general curvature of said spring and being made long enough to span several of the work-holding pockets.

The shoes are spring-tensioned as follows. Each shoe is pivoted at 45, 45 on an arm 41, 48, which in turn is pivoted between its ends at 49, to base II (see Fig. 4). To the free end of each arm 49, 50 is fastened one end of a coil spring, 5|, 52, the other end of each spring being anchored to any fixed point as at 53, 54 (see Fig. 2). As a result of this construction, the shoes are constantly urged by the springs 5|, 52 into pressure engagement with the band spring l8, but may yield outwardly to prevent breakage of the parts should such be required.

The finished blanks are discharged one at a time from the feed wheel by means of an ejector spring 55 or its equivalent. (see Fig. 2) fixed in the path of the wheel in the region of the cutout A which acts to rem ve each finished blank from its holding pocket as the wheel rotates therepast. From the ejector 55 the finished blanks discharge down chute 55 into any suitable collection receptacle (not shown) In operation, with the grinding wheels set to make the required grinding cuts, and both the feed wheel and the grinding wheels revolving, the pockets of feed wheel are loaded with blanks, beginning at approximately the point I9 in Fig. 3. As said Wheel rotates in the direction of the arrow in that figure the exposed upper ends of the blanks are successively carried beneath and acted upon by the pair of grinding wheels. When the feed wheel substantially completes its revolution, the finished blanks are ejected one at a time by ejector 55. While the grinding wheels are at work on the blanks, the

pressure shoes

43, 44 acting through retaining spring 18, press them firmly into their pockets.

From the foregoing description it will be evident that the operation is continuous and positive. By changing feed wheels, blanks of different diameters and lengths may be worked upon.

While I have shown a practical embodiment of my invention which satisfactorily fulfills its intended purpose, I recognize that my machine is susceptible of various changes in design and arrangement. For example, it might be equipped with an automatic blank feeding device. Or for some grading operations, only one grinding Wheel might be required.

These and similar modifications are to be regarded within the scope of my invention as defined in the appended claims.

What I therefore claim and desire to secure by Letters Patent is:

1. A grinder, comprising a feed wheel having a peripheral series of spaced pockets of a shape and depth each to contain a blank endwise therein with one end of the blank projecting beyond one face of said feed wheel, means for rotating said feed wheel in a constant direction,

a grinding wheel positioned to rotate in a path which intersects that described by the projecting ends of the blanks contained Within the pockets of the feed wheel, means for rotating said grinding wheel, means for confining the blanks in said pockets for a portion of the revolution of said feed wheel, and means for applying additional pressure against the blank-confining means at that portion of the arcual travel of the blanks at which they are acted upon by said grinding wheel thereby to seat the blanks tightly in the pockets while they are being acted upon by said wheel, and means for successively ejecting the finished blanks from said pockets after they have been acted upon by said grinding wheel. 7

2. A grinder comprising a frame, a base surrounding the frame, a feed wheel rotatable in a horizontal plane over said base and having a peripheral series of spaced vertically disposed pockets of a shape and depth each to contain a blank endwise therein with one end of the blank projecting beyond the upper face of the feed wheel, means for continuously rotating said feed wheel in the same direction, a pair of spaced oppositely disposed grinding wheels rotating about spaced alined axes over the upper face of the feed wheel in paths which intersect that described by the projecting ends of the blanks contained in the pockets of the feed wheel, means for continuously rotating said grinding wheels, means for confining the blanks in said pockets during a substantial portion of the revolution of said feed wheel and while said blanks are being successively acted upon by said grinding wheels comprising a band spring encircling aportion of the periphery of the feed wheel and spring-tensioned pressure shoes for exerting prcssureon said spring at those portions thereof at which the grinding wheels are acting upon the blanks thereby to seat the blanks tightly. in the pockets oithe feed wheel while they are being acted upon by the grinding wheel, and means fixed in the path of said feed wheel for successively ejecting the finished blanks from said pockets after they have been acted upon by both grinding wheels.

ARDEN B. MACNEILL.