US 2345884 A
Description (OCR text may contain errors)
April 4, 1944. w. 1. POWERS, JR., ETAL 2,345,884
TURRET CONVEYER Filed Jan. 1s, 1943' Patented Apr. 4, 1944 UNITED STATES PATENT'OFFICE TURRET CONVEYERJ Application January 13, 1943, Serial No. 472,212 f 2 Claims.
This invention relates to automatic machines, and, particularly, to an improved sealing means or spindles of automatic machines of the turret YDS.
'I'he automatic machine, herein disclosed, is adapted specifically to de-iln and paint frangible targets, and, in this respect, is especially well suited to illustrate the present invention.y
It will be understood, however, that the present invention may be used with other types of machines and moreoveris not limited by the present disclosure, but is capable of many other embodiments and uses without departing from the spirit and scope ofthe invention as dened in the appended claims.
An important object of the invention is to seal the spindles in the turret head so as to maintain a pressure differential in the turret. A further object is to provide packing rings on the spindles for equalizing the pressure on opposite sides of the spindle bearings while a reduced pressure exists within the spindles.
Other objects, features and improvements will appear hereinafter.
In the drawing:
Fig. 1 is a schematic fragmentary front elevation of a machine especially adapted to illustrate the invention.
Fig. 2 is an enlarged sectional view of the details of the spindle supporting means.
Fig. 3 is an enlarged sectional view of a port tion of the spindle showing the sealing means of this invention.-
The frangible targets which are handled by themachine, illustrated herein, are substantially dish-shaped articles molded from a mixture comprising clay and pitch or possibly limestone and pitch in the proportions roughly of 45% clay (or limestone) and 55% pitch. These vfreshly molded targets are extremely fragile and hence require delicate handling while being subjected to the finishing operations.
As hereinafter described, the means for holding the targets while they are being cle-finned and painted comprises a hollow spindle, the targets being held on the lower ends of the spindles by suction effected by a suitable exhaust pump.
The de-nning operation, which is of special interest in regard to the present invention, is performed by rotating the targets in Contact with suitable abrading blocks which are yieldingly urged against the target so that ns and-the like imperfections will be removed by the abrasive as the spindles a-ndtargets rotate.
Although machines of this type are used exi tensively and meet with considerable succees,
it has been found' that, after? continuous use for a relatively short period, the parts of the machine, and, in particular, the spindle bear-ings, are worn to such an V'extent-'as to interfere with the efficient operation of the machine. This excessive wear in the rspindle bearings has been attributed to the Vfact that a reduced pressure exists within the spindle bearings whenever a target is held on the spindle by the suction means. Consequently, the ne dust-like particles of target material removed during the abrading operation are drawn intothe spindle bearings. Moreover, since the target material itself is in the nature of a soft abrasive, its presence in the bearings wears out the bearings with great rapidity.`
The present invention'discloses means for overcoming the tendency for :the dust-like abrasive material to enter rthe spindle bearings by maintaining a normal atmospheric pressure Within the bearings.
Referring to the drawing, a part of the target painting and de-nning machine is Ashown schematically in Fig. 1. Briefly, the machine comprises a frame Illy which supports feeding mechanism for carryingthe targets I2 to a loading mechanism (not shown). The loading mechanism includes selecting means' for allowing only certain targets to pass to a loading platform I4 and transferring and lifting means I5 for moving the targets to a set of target holding spindles Il supported on a rotatable turretIS. For a more complete disclosure of the invention,A reference may `be had to arcopending application of Warren S. Reynolds, Serial No. 371,288,1-lled December-23, 1940.
The target supporting spindlesV I"I to which this invention particularly relates, are carried' on the turret head I6 as shown'jin Fig. 2 which is rotatably supported on the shoulders I8 of a turret supporting member I9 fixed' to the frame of a machine. The turret head includes a plurality of spindles I 1, four being shown in the present embodiment, suitably supported for rotation in sleeves 2li of the turret head' by sleeve'bearings 2l Aand 22 which are fitted into the ends 23 and 24 respectively of the sleeves 20. These sleeve bearings 2i and 22 are hereinafter referred to as the spindle bearings. The outside or overall dianieter oi each spindle is less, than'the vinside diameter of the sleeve 20 by an amount equal to twice the thickness ofthe walls of the spindle bearings plusV sufficient Aclearance between the spindle andV its bearin'gsto provide a smooth rotatable fit. Consequently, the portion of each spindle intermediate its bearings 2| and 22 is spaced from the adjacent walls of the sleeve thus producing an annular passage 26 therein, see Fig. 3. Adverse Vertical movement of each spindle in its 4bearings is prevented by a ange 2T and thrust washer 21 on the spindle adjacent the upper end of the sleeve and a shoulder or flange 28 formed by a nosepiece 29 screw threaded in the spindle adjacent the lower end of the sleeve.V
By properly tightening the nosepiece on the threaded end of the spindle, the thrust washer 21' and shoulder 28 are drawn against the respective ends of the spindle bearings as shown. Y
Each spindle has a suitable pulley 30 secured to its upper end for driving the spindle and a suitable work head, indicated generally at 3|, at its lower end which comprises the nosep-iece 29 and a locator ring 33. The latter comprises a closed ring having a tapered rim 34 adapted to provide a seat for the target and to this end is mounted loosely on the nosepiece 29 so as to move freely up and down thereon. The ring 33 has an inwardly projecting iiange 35 on its upper edge adapted to extend over the shoulder 28 to keep the ring from sliding down oi of the nosepiece 29. Each work head 3| is provided with an annular gasket 36 at its lower end fitted into a suitable recess 31 in the nosepiece 29. Thus a frangible target l2 may be pushed against the rim 34 of the locator ring 33 and the latter is free to lift or rise with respect to the nosepiece until the inside of the, target is in engagement with the face of the rubber gasket 36, whereupon suitable suction means, indicated generally at 38, is used to retain the target in this position while it is transferred to the several operating stations. The suction or vacuum means 38 for holding the targets against thework heads comprises a system of passages leading from the work head 3| through the spindle I1 and turret head I6 into the turret supporting member |9 to which a suction pipe 39 is connected. Specically, each spindle Il includes an axial-bore 4D in communication with the rubber gasket 36 and extending through the hollow work head 3| upwardly to a point somewhat beyond the center of the spindle. It will be evident that the bore 4|) occupies a major portion of the spindle and hence the latter will be hereinafter referred to as a sub- A stantially hollow spindle. Adjacent the upper endV of the axial bore 40, there are provided suitable transverse holes 42, see Fig. 3, which open into the annular passage 26. Thence a radial bore 43 extends from the annular passage 26 through the turret head I6 to an inner wall 44 thereof where it becomes associated at intervals during the rotation of the turret with grooves or channels 45 which extend around the wall 46 of the xed turret supporting member I9, these channels being connected in turn by suitable passages 4`| and 48 to the pipe 39 of a suitable exhaust pump (not shown). It will be evident that, when the exhaust pump creates suction in the above identied passages, a partial vacuum or reduced pressure exists within the sleeve 20 and hollow spindle as a consequence of which a target will be held on the work head 3l of the spindle. The annular passage 26 insures suction within the bore 49 of the spindle from the radial bore 4?., even while the spindle is rotating. Moreover, inasmuch as the spindle is adapted to have a freely rotatable fit in its bearings 2| and 22, this reduced pressure exists Ain these bearings and also at the bearing surface formed between the shoulder 26 and the lower end of the bearing 22. It will be clear then that, during the abrading process, the dust-like abrasive particles will be drawn into the spindle bearings due to the pressure differential between the outside and inside of the sleeve.
To prevent this adverse circumstance, means are provided for equalizing the pressure on opposite sides of the spindle bearings.
To this end, a pair of apertures 49 and 56 are l made in the wall of the sleeve 2|! of the turret head, the aperture 49 being slightly below the upper spindle bearing 2| and open to the atmosphere and the aperture 50 being slightly above the lower spindle bearing 22 and also open to the atmosphere. Furthermore, a pair of pneumatic seals or packing rings indicated generally at 52 and 53 are supported on the portion 25 of the spindle adjacent opposite ends thereof which make a tight sealing fit with the inner walls of the sleeve and the periphery of the spindle. The upper ring is positioned slightly belowA the upper aperture -49 and the lower ring is slightly above the lower aperture 59. Rings well adapted to this purpose may comprise a duplex structure consisting of molded rings 54 of sealing material, such as suitable rubber, neoprene or other sealing composition assembled with V-shaped flexible metal springs or spreaders 55 into a metal case 56 and combined into a unit by an adapter ring 51 which holds the sealing rings and springs rmly in place. The metal case 56 is tted securely into the bore of spindle holder or sleeve 2D, the margin of each body of sealing-material 54 being in sealing contact with the periphery of the portion 25 of the spindle.
It will be manifest, therefore, that that portion of the annular passage between the sealing rings 52 and 53 is eiectively sealed from the extremities of the passage 26 adjacent the apertures @9 and 56. Consequently, the extreme ends of the passage 26 and hence the spindle bearings 2| and 22 will be at atmospheric pressure and will remain so irrespective of any changein pressure within the sealed passage 26 of thesleeve; that is to say, a partial vacuum may exist in the sleeve and hollow spindle to hold a target on the head without creating suction in the spindle bearings 2| and 22 and thus the probability of drawing dust or other abrading materials into the beare ings is effectively prevented. Y
What is claimed is:
l. In an automatic target de-nning machine, a frame; a turret head supported on said frame;
. a sleeve carried by said turret head, said sleeve having radial apertures at opposite ends thereof open to the atmosphere; a substantially hollow spindle; spindle bearings in said sleeve adjacent said apertures for rotatably supporting said spindie, said bearings being constructed and arranged to form an annular passage in said sleeve intermediate the ends of said spindle; packing means on said spindle for sealing said passage from said bearings and said apertures whereby atmospheric pressure is positively maintained on both sides of said bearings; and suction means carried by said turret head for securing reduced pressure within said annular passage and said hollow spindle to hold a target on one end of said spindle.
2. In a multiple spindle turret target de-fnning machine, a fixed central support; a turret mounted on said support; sleeves carried by said turret, at least one of said sleeves having radial apertures through its walls at opposite ends thereor" open to the atmosphere; a substantially hollow spindle; spindle bearings at the extreme ends of said sleeve beyond said apertures for rotatably supporting said spindle, said bearings dening the ends of an annular passage formed between the inner wall of said sleeve and the periphery of said spindle and in communication with the hollow of said spindle; suction means carried by said central support and turret for securing reduced pressure within said annular passage and the hollow of said spindle to hold a target on one end of said spindle; and a pair of sealing rings in said sleeve between said apertures and on opposite sides of the turret suction means for sealing said annular passage from said bearings whereby atmospheric pressure is positively maintained at the opposite ends of each spindle bearing.
WILLIAM J. POWERS, JR. FORD H. MCBERTY,