US2199297A - Mill housing - Google Patents

Description

April.30, 1940. A. s. VILLASUSO MILL HOUSING Filed Dec. 14, 1936 I 2 Sheets-Sheet 1 3 went 1' A 5. V)//ysus0 o April 1940- A. s. VILLASUSO 9.2

MILL HOUSING Filed Da. 14, 1936 2 Sheets-Sheet 2 lhwentor y, S wlgzsasa Patented Apr. 30, 1940 UNITED STATES MILL nousmo Armando Saturnino Villasuso, Tucuman,

. Argentina Application December 14, 1936, Serial No. 115,843

1 Claim.

The invention relates tomill housings and in particular to housings for cane-mills in which hydraulic pressure is applied to the upper. roll.

The general practice heretofore has beento position the ram vertically over the journal of the upper roll and to apply the pressure directly at this point. As is well known, the object of applying the hydraulic pressure to the upper roll is to maintain the roll normally in a lowermost position while permitting the r'olls to move apart upon a sudden passage of an abrupt heavy mass of bagasse between the rolls, and the roll which is actually moved is the said upper roll. u The construction outlined above sufiers from two disadvantages, namely, the scraping of the outside of the upper brass of the upper roll by the adjacent housing parts, and the alteration of the ratio of the clearances between the input roll and the upper roll and between the output roll and the upper roll. It has been suggested to overcome the first difliculty by shifting the position of the ram circumferentially with respect to the upper roll journal so that the center line of the ram coinci-des approximately with the direction of maximum thrust, and arranging for the upper brass of the upper roll to move between guiding surfaces which extend parallel tosaid direction of maximum thrust. This attempt has not, however, met with success'in practice since, although the upper brass is less exposed to scraping,'an even greater departure than usual from the ratio .of the clearances between the rolls occurs upon upward movement of the upper roll, owing to the particular construction of the housing.

It has been found advantageous in practice to position the rolls so that the ratio between the clearance between the input roll and the upper roll and the upper roll and the output roll is'in the neighbourhood of threeto one. For example, the clearance between the input roll and the upper roll may be mms. and that between the upper roll and the output roll 5 mms. clear to those skilled in the art that if the upper rollis caused to move vertically away from the other two for instance, a distance of 5 mms., the clearances will then be approximately mms. between the input and upper rolls and 10 mms.

between the upper and output rolls, giving a ratio r of two to one. If the upper roll is supported in accordance with theabove indicated'prior suggestion, it is found that the gain in clearance between the output roll and the upper roll is much It will be of three to one is again destroyed by movements of the upper roll. 3 v The principal object of the presentinvention is v to provide an improved mill housing which will allow of movements of the upper roll away from the two lower rolls without disturbing the ratio between the clearances. I

Another object of the present invention is to provide a mill housing in which the hydraulic pressure is applied indirectly to the upper roll.

A further object of the present invention is to provide a mill housing in which the upper brass of the upper roll is held in position by acap member which is pivoted to the housing at one end and has at its other end a tongue or the like projection forming a thrust surface for the hydraulic ram, means being provided for holding said upper brass against relative movement with respect to said cap.

Other objects and advantages of the present invention will appear in the course of the following detailed description of a preferred embodiment, illustrated in theaccompanying drawings, in which:'

Fig.1 is a side elevation of a housing embodying the improvements according to the present invention.

Fig. 2 is a plan of the-housing of Fig. 1 with the cap removed. l

Fig. 3 is an end view of the housing of Fig, 1 partly in section andv I Fig. 4 is a perspective view of the cap, partly in section. v

As shown in the drawings, the housing consists of a main frame It] supporting in its lower portion the adjustable right and left hand bearing blocks 12 and M in which rest the journals l6 and !8 of the output and input rolls 20 and 22, respectively. The bearing blocks I2 and 'l 4 rest as usual upon the slide ways 24 and 26 forming the lower boundary of the usual open- ended recesses 28 and 30 of the frame l0, and said bearing blocks are adjustably secured in position by the screws 32, 34 passing through the usual end-covers 36,

. 38 which are securely held against the ends of the main frame by the long bolts Ill-and nuts 42, the frame having semi-circular formed in its sides to accommodate a half of'said bolt 40.

The bearing blocks I2 and M are made hollow as usual and fitted with inlets l3 and outlets I5 for cooling water. 1

In the upper portion of the main frame there is centrally and freelysupported the lower brass along the line III-III of Fig. 1,

channels 44 e 46 on which normally the journal 48 of the upper roll 58 rests. The upper roll is normally held down on to said lower brass by means of a cap 52 which, at one end is pivoted to the frame excentrically with respect to said journal 48 by means of a pin 54 and at its other end has a tongue 56 which projects into a space 58 formed in an upwardly directed extension Ell of the main frame. Said extension 60 is located to one side of and inclined towards the journal 48 of the upper roll 50, and terminates at its upper free end in the hydraulic cylinder 62, the ram 64 of which bears against the upper surface of the tongue 56 and thus exerts a downwardly directed pressure indirectly upon said journal 48.

Between the journal 48 and the immediately adjacent portions of the cap 52 the upper brass 66 is interposed, said brass being provided with means, for example the projections 68 which cooperate with corresponding recesses 58a cut in the cap, for preventing relative movement betwee said upper brass 66 and the cap 52.

As best seen in. Fig. 4, the cap 52 is hollowed out in the portion adjacent the upper brass '66 rolls.

and fitted with an inlet (not shown) and an outlet 53 for cooling water. The open end of the hollowed out portion is in the assembled condition of the housing closed by the upper brass, in the same manner as are the hollows of the bearing blocks l2 and I4 by their 'brasses iZa and Ma (see Fig. 1).

Means are likewise provided for lubricating the journals of the rolls. The means used for the journals IE and it of the lower rolls are not indicated as any of the. lubricating systems usual in this type of housing may be applied.

One form of lubrication arrangement which can be suitably applied to the cap 52 is, however, illustrated.

In accordance with this arrangement, an oiling tube 90, the lower end of which is adapted to be screwed into the upper brass 65 of the upper roll, is secured as by screws 9! passing through the flange 93 at its upper end to a boss 32 formed on the cap 52 and is likewise adapted to be coupled to a source of lubricant, for example the cup 98. The lubricating system is thus completely closed with respect to the cooling water circulating in the hollow space 96.

This arrangement has the advantage that owing to the lever effect of the cap the indirectly applied hydraulic pressure may be considerably reduced while at the same time sufilcient force is available at the journal 58 to maintain the upper roll 50 in its normal position under normal conditions of operation. Consequently, it is possible Without adversely affecting the operation of the mill, to reduce the pressure in the hydraulic pipelines and to reduce the dimensions of the cylinder 62 and ram 64 thereby effecting considerable economy. A further advantage of my novel construction is that by suitably selecting the location of the pivot 54, I can maintain substantially constant the ratio of the clearances between the By preventing relative movement between the upper brass 65 and the cap 52 I entirely eliminate the excessive wear on the outside of said brass which, in known constructions, occurs owing to scraping action to which I have already referred.

The width of the main body of the cap 52, measured in the direction of the axis of the upper roll, is preferably the full width of the distance between the end flanges of the brass 66. In order to avoid laterally overhanging parts, both the tongue 55 and the opposite end 10 of the cap are reduced widthwise, the tongue as stated above projecting into the space 58 provided for that purpose in the extension 60 and the opposite end 1G, which is drilled as shown at 12 (Fig. 4) to receive the pin 54, is located between a pair of projecting guides 74 formed in the upper part of the housing on the side of the brass 46 remote from the extension 50. Preferably a depression 5! is formed in the upper surface of the tongue 56.

As best seen in Figs. 2 and 3, the cylinder 62 is fitted with a connection 16 adapted to have coupled to it the hydraulic supply pipe (not shown) and communicating with the space 18 within the-cylinder, said space being as. usual defined between upper and lower plates 80, 82 the former of which is retained by the screwed closure member 84 while the latter rests on the head (not shown) of the ram 64.

he constructional details of the hydraulic cylinder, the ram, the lower portion of the housing, the end plates and bearing blocks may be modified as desired without interfering with the essential features of my invention which comprise the eccentric-ally pivoted cap 52, the application of the hydraulic pressure to the end of the cap remote from the pivot and the location at a convenient point between the two ends thereof of the bearing for the journal 48 of the upper roll, the upper brass of said bearing being held by suitable means against relative movement with respect to said cap.

The ope-ration of the improved housing, which has already been in part alluded to, can readily be followed from the drawings. When an abrupt heavy mass of bagasse attempts to pass between the rolls the upper roll is subjected to a resultant upward thrust which is generally inclined from the vertical and extends at right angles to the upper surface of the extension 60. This resultant thrust, the exact direction of which depends upon the general design proportioning of the housing, is transmitted to the journal 48 and brass 66 to the cap 52 and by the tongue 56 of the latter to the ram 64 which is forced back. thus allowing the cap 52 to swing about its pivot 54 and increase the clearance between the upper roll 59 and the input roll 22 in order to allow the bagasse to pass. Owing to the position of the pivot 5 with respect to the journals 48 and I6, it is clear that the upper roll 50 will, in moving away from the outlet roll, also have a component of motion about the centre of the journal l5 so that the point of closest proximity between the upper roll 50 and the output roll 20 will travel around the circumference of the output roll in a direction away from the input roll 22 or, in other words, towards a higher portion of the circumference of the output roll 25). Thus the separation movement between the upper roll 50 and the output roll 20 is, to a certain extent, compensated by the difference in level of the point of closest proximity. On the other hand, over the short distances which have in practice to be considered,

the motion of the upper roll is almost radially away from the input roll 22. By suitably selecting the position of the pivot 54 with respect to the centres of the three journals l6, l8 and 48 the compensation to which reference has just been made can be so adjusted that the ratio of the clearances between the upper roll 50 and the input roll 22 and the upper roll 50 and the output roll Zil may be maintained substantially constant.

What I claim is:

In a mill housing for sugar-cane mills, a main frame, input and output rollers rotatably supported in spaced relation in said frame, an upper roller associated with said frame, means including brasses for supporting said upper roller in a position intermediate said lower rollers, acap' member for holding one of said brasses in contact with said upper roller, a pin pivotally connecting the cap member to said housing, said pin being positioned below the axis of the upper roller and so located that upon movement of the upper roller as a result of the thrust of masses of cane passing through said rollers the'ratio of the clearances between one of said lower rollers and the upper roller and the other of said lower rollers and the upper roller will remain substantially constant, the'other end of said cap having a tongue which penetrates into said housing, said housing having a cylinder cast integral-therewith and containing a hydraulic ram positioned immediately above and engaging said'tongue, and the axis of said cylinder being arranged at a tangent to the movement of said tongue.

' A. s. VILLASUSO.

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