US1594854A - Shaking screen - Google Patents

Description

Aug. 3 1926. 1,594,854

' P. S. SAVAGE SHAKING SCREEN Filed July 31 1923 2 Sheets-Sheet 1 Patented Aug. 3, 1926.

UNITED STATES PATENT OFFICE.

PHILIP S. SAVAGE, OF BUFFALO, NEW YORK, ASSIGNOR, BY DIRECT AND MESNE AS- SIGNMENTS, TO ROBINSOONVEYING- BELT COMPANY, A CORPORATION OF NEW 'JEnsEY.

SHARING SCREEN.

Application filed July 31, 1923. Serial No. 654,849. 7

This invention relates to improvements in shaking screens designed more especially for the screening of coke or other coarse granular material.

The principal objects of the invention are to provide a screen in which an improved shaking eifect is obtained, resulting in more certain and effective separation of the coarser and finer particles, greater output of work and less abrasion and wear of the screening grid; a suitable degree of rapidity and amplitude of vibra-- tion is developed without thereby involving any liability of undue wear or racking; and the vibratory throw of the screen frame may be readily and certainly regulated in order to best adapt the screen to the individual characteristics, e. g. weight,

consistency and form, of the particular material to be treated; and which isexceedingly simple in its organization, being devoid of any mechanism which is liable to de rangement or undue wear or, in consequence of wear, to produce any failure or unevenness of action.

With the above objects in view the invention consists generally in the novel combination and arrangement of the screen frame and the elements constituting its actuating and supporting means, the organization being characterized by the mounting of the screen frame for pivotal movement about its actuating means as an axis, and the provision of resilient means connected to said frame distant from said actuating which permits of longitudinal vertical displacement of said frame and is self-synchronizing with reference to the action of said actuating means.

An embodiment of the invention is illus trated in the accompanying drawings, wherein Figure 1 is a plan view of the shaking screen. I

Figure 2 is a side elevation.

Figure 3 is a detail plan view of one of the spring supports.

Figure 4 is a side elevation of the same.

Figure 5 is a sectional view on the line 5-.5 of Figure 4.

at a point means and supporting as well as 1 is reciprocated preferably consists of ec centrics 3 mounted on a transverse operating shaft 4. The supporting frames 2 are provided with bearings 5 for the shaft 4 and the side bars of the frame 1 are provided with hearings or straps 6 in which the eccentrics 3 are journaled. The shaft 4 is arranged at a suitable point between the ends of the frame 1 and serves as a supporting element for said frame which is otherwise yieldingly supported at or near one end from the frames 2 whereby it may rock about the eccentrics 8 as an axis.

As shown, the frame 1 is yieldingly supported at its upper end, the supporting means preferably comprising leaf springs 7 arranged cantilever-wise and links or shackles 8 pendent from the free ends of the springs 7 and' pivoted at their lower ends to the side bars of the frame 1. The springs T are fitted in and project substantially to an equal extent from boxes 9 provided on the supporting frames'2 and in each instance bear upon a shoulder 10 at the front of the box 9 and which forms the lower wall of the opening 11 through which the spring projects, the effective length of the springs being determined by the extent to which they project beyond the shoulders 10. Within the boxes 9 the leaves of the springs are clamped together by upper and lower plates 12 and 13 connected by bolt andnut fastenings 14. The plates 12 and 13 also serve as hearing plates, the plate -13 engaging or seating upon the bottom of vides a bearing for an adjusting screw '19- through the upper wall of the box 9 and being held fast by lock nuts. The inner side wall and the top Wall of each'box 9 is provided by an angle member 16 which is secured by bolts 17 to the frame 2 and projects rearward from the box- 9, at its-rear end being; formed with a web 18 which proby means of which the position of the spring 7, and hence the extent to which said spring PI'OJGCtS, may be regulated. The

screw 19 isprovided at its rear end with a hand wheel 20 a' nd at its opposite end projects into the box 9 and is connected by a swivel coupling 21 with the rear end of the spring 7. In the adjustment of the springs 7 the. screws 15 are first backed off to relieve the pressure on the springs and the screws 19 arethen manipulated to advance or retract the springs 7 accordingly as the effective lengths of said sprin s are to be increased or decreased, after w ich the screws 15 are tightened in order to secure the springs against displacement.

,In operation, as the screen frame is vibrated by the eccentrics it is also caused by the springs 7 to rock about the eccentrics as an axis, whereby the vertical movements of the ends of the screen frame are in the same directions at the same periods of operation and are preferably of the same extent. However,'the upper or intake end of the screen frame may be caused to have elther a somewhat greater or a somewhat less degree of vertical vibration than the discharg end andeither of these arrangementsmay occasionally be of advantage, according to'the existing conditions. The eccentrics may rotate either clockwise or counter-clockwise according to choice as dictated by existing conditions, a clock-..

wise rotation of the eccentrics having the effect of accelerating the flow of aterial along the screen frame and "a coun r-clockwise rotation of the eccentrics having the effect of retarding the flow of material along the screen frame. The vertical vibrations of the screen frame have a peculiar snap or definiteness which is due to the action of the springs 7 and has the effect of bouncing the material on the screening grid; that is to say, while the frame is ap-- preaching the end of eachsucceeding stroke the springs are drawn forcibly down to a limited extent by the pull of'the links thereon, but in the initial movement of each 'succeeding stroke the tension of the links on the springs is'relieved and in conse-1 links sharply rebound or snap upward in' a manner to impart the described vertical vibrations to the screen frame. A plurality of snapping vertical impulses are thus given to the frame during each reciprocation thereof by the eccentric connection'. The rapidity and dequence the they are gree of the bouncing actions are such that they are effective in causing the discharge of the finer portions of the material through the meshes of the screening grid. The working capacity of the screen is thus enhanced while at the same time the drag of the material on the screening grid is reduced to a minimum and consequently there is a reduction-1 of the abrasive effect of the material on the screening grid so that the latter lasts longer and gives better service. The bouncing action described is of substantial advantage in any case, for the reasons noted, but it is 'of particular advantage where the material is in a somewhat damp or moist condition, whereby its particles tend to cohere.

The rapidity and extent of the vibrations are to be determined in accordance with the characteristics of the material to be treated, the coarser and heavier materials being more efiectively separated by vibrations of less frequency and greater amplitude and the lighter and finer materials being more effectively separated by vibrations of greater frequency and less amplitude. The speed and diameter of the eccentrics are accordingly selected to meet the conditions of the particular work for which the screen is intended and the springs 7 are adjusted whereby their action, due to their effective length, is co-ordinated to the action -of the eccentrics.

The eccentrics maybe located as desired along the length of the screen frame but preferably located about a third, more or less, of the total length of the scfreen frame from-the discharge end there- 0 r The operation of the screen in any case has the characteristics above pointed out. However, the particular action produced will depend upon the co-relation' of several factors, viz.,v the location of the eccentrics along the length of the screen frame, the rapidity,j -throw and direction of rotation of the eccentrics fective length of the springs 7; and consequently as regards the action of the screen a certain range of selection is available involving the selection and co-ordination of the factors above stated, whereby the engineer who designs the screen may best lar work for which it may be intended.

Having fully described my invention, I claim v 1. In a shaking screen, in combination, a screen frame, an operating eccentric about which said frame may pivot and which participates in its support, and resili ent supporting means for 'said frame located at a distance from said eccentric, said means being constructed and arranged to impart a plurality of snapping vertica andthe strength and eflocated at a distance from said eccentric and connected to the upper end thereof, said means being constructed and .arranged to impart a plurality of snapping vertical impulses to the frame during each reciprocation thereof by the eccentric, and comprising a spring member and a link connection between said member and the frame.

3. In a shaking screen, in co mbination, a screen frame an operating eccentric about which said frame may pivot and which participates in its support, and a leaf spring and. link connection supporting said frame at a distance from the eccentric.

4:. In a shaking screen, in combination, a screen frame, an operating eccentric about which said frame may pivot and which participates in its support, a leaf spring arranged cantilever-wise, and a link connecting the free end"of said'spring with the frame at a distance from the eccentric.

5. In a. shaking screen, in combination, a screen frame, an operating eccentric about which said frame may pivot and which participates in its support, a leaf spring arranged cantilever-wise, a link connecting the free end of said spring with the frame at a distance from the"ec-- centric, and adjusting means for varying the effective length of said spring.

6. In a shakingscreen, in combination, a screen frame, an operating eccentric about which said frame niay pivot and which participates in its support, and resilient supporting means for said frame compris-.

ing a pair of leaf springs and links connecting said springs to. said frame at points distant from said eccentric.

7. In a shaking screen, in combination, a screen frame, an operating eccentric about which said frame may pivot and which participates in its support, resilient supporting means for said frame comprising a pair of leaf springs arranged cantileverwise and links connecting the ends of said springs to said frame at points distant from said eccentric.

, 8. In a shaking screen, in combination, a screen frame, an operating eccentric about which said. frame may pivot and, which participates in its support, resilient supporting means for said. frame comprising a pair of leaf springs arranged cantileverwise and links connecting the ends of said springs to said frame at points distant from said eccentric, and adjustable means for varying the effective length of said springs. I

9. In a shaking screen, in combination, an inclined screen frame, an operating cccentric about which said frame may pivot and which participates in its support and resilient supporting means for said frame comprising a pair of leaf springs arranged cantilever-wise and links connecting r the ends of said springs to said frame at points near the upper end thereof and distant from said eccentric.

10. In a shaking screen, in combination,

an inclined screen frame, an operating eccantilever-wise and links connecting the ends of said springs to said frame at points near the upper end {thereof and distant from said eccentric, and adjustable means for varying the effective length pf said springs.

. 11. In a shaking screen, in combination, a screen frame, an operating ecentric about which said frame may pivot, springmeans acting on said frame in consequence of the operation of said eccentric to cause said frame to rock relatively to said eccentric as an axis, and to impart a plurality of snapping vertical impulses to said frame during each reciprocation thereof by the e0- centric, said means comprising a spring member and a link connection between said member and 'the frame, and adjustable means for modifying the action of said springsl 12. In a shaking screen, in combination,

a screen frame, means for yieldingly and ing a leaf spring arranged cantilever-wise,

and a link connecting the free end of said spring with the frame, and actuating means pivotally connected to said frame at a distance from said supported end and operating to reciprocate said frame.

13. In a shaking screen, in combination, a screen frame, actuating means pivotally connected to said frame and operating to reciprocate the same, and resilient means acting upon said frame at a point dlstant from said actuating means to cause said frame to rock aboutthe axis of its pivotal connection with said actuating means during and in consequence of the operation of said actuating means whereby the ends of said frame move in the same vertical di- V rections at the same period of time, said resilient means being constructed to impart a plurality of snapping vertical impulses to the frame during each reciprocation thereof.

14. hi a shaking screen, in combination, a screen frame, actuating means pivotally connected to said frame and operating to reciprocate the same, resilient means acting upon said frame at a point distant from said actuating means to cause said frame to rock about the axis of its pivotal connectlon with said actuatlng means during and in consequence ofthe operation of said actuating means whereby the ends of said frame move in the same vertical directions at the same period of time, said means be ing constructed to impart a plurality of snapping vertical impulses to the frame during each reciprocation thereof, and means for adjusting the tension of said resilient means.

In testimony whereof I aflix my signature.

PHILIP S. SAVAGE.

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