US3403552A

US3403552A - Chain tension adjusting apparatus

Info

Publication number: US3403552A
Application number: US583727A
Authority: US
Inventors: Maurice J Erisman
Original assignee: FMC Corp
Current assignee: FMC Corp
Priority date: 1966-10-03
Filing date: 1966-10-03
Publication date: 1968-10-01
Anticipated expiration: 1985-10-01

Description

Oct. 1, 1968 M.J. ERISMAN CHAIN TENSION ADJUSTING APPARATUS 2 Sheets-Sheet 1 Filed Oct. 3, 1966 5 2 3% 4 c 1 w 9 w w w, U m 333 33% 1968 M. J. ERISMAN CHAIN TENSION ADJUSTING APPARATUS 2 Sheets-Sheet 2 Filed Oct. 3, 1966 Edema .6 (ma-r2:

United States Patent 9 3,403,552 CHAIN TENSION ADJUSTING APPARATUS Maurice J. Erisman, Oak Park, Ill., assignor to F MC Corporation, a corporation of Delaware Filed Oct. 3, 1966, Ser. No. 583,727 8 Claims. (Cl. 73-443) This invention relates generally to traveling water screens and more particularly to an apparatus for measuring and selectively adjusting the tension in the chains which carry the moving screening trays.

Traveling water screens are installed in a substantially vertical manner and form a part of a water intake system through which water flows prior to the point of treatment or usage. As the raw water passes through the screening trays of the traveling water screen, the refuse in the water is retained on the screening medium and is elevated for removal during the periodic operational cycles of the traveling water screen. As each screen tray is lifted out of the water the refuse is dislodged from the screening medium and is carried away for disposal.

A traveling Water screen consists of a pair of transversely spaced vertically extending side frame members having a head shaft and a foot shaft parallelly arranged and rotatably supported between the upper and lower end portions respectively of the side frame members. A pair of transversely spaced endless chains are supported over a corresponding pair of spaced sprockets on the head shaft and extend vertically downward therefrom to be trained around an associated pair of vertically aligned foot sprockets on the foot shaft. A series of individual screening trays are mounted between the chains and supported thereby in a manner to define an endless screening medium.

For the traveling water screen to function properly, the chains should be operated and maintained at the tension value which will assure the proper operative engagement of the chains with their associated sprockets. This is accomplished by rotatably supporting the opposite ends of the head shaft in bearing blocks which are sl'ideably moveable endwise along the side frame members. Each of the bearing blocks is supported by an elongatively adjustable structure so that the head shaft can be adjusted to vary the distance between the head shaft and the foot shaft, thereby adjusting the tension in the associated chains.

It is apparent that the chains must be sufficiently tensioned in order to remain in the proper operative engagement with the foot sprockets, and yet must not be over tensioned to avoid interfering with the running freedom of the chains. If the chains are loose, undue wear will occur to the chain and the chain guides, and should the chains be extremely loose, damage to the traveling water screen will result from the accumulation of excess slack in the chains where they are trained around the foot sprockets. If, however, the chains are overtightened, the excessive strains placed on the chains will cause undue wear to the chains, and will also interfere with the operational freedom of the screening trays. It is therefore apparent that an apparatus which would permit the accurate tensioning of the screen chains would alleviate the abovementioned problems and thereby extend the useful life of the associated chains and sprockets.

As wear occurs in the chains and associated sprockets, the tension of the chains decreases accordingly. Reestablishment of the desired tension is usually obtained by manipulation of an adjustable structure in a manner to tighten the chains until they appear to be in the proper engagement with the foot sprockets while still maintaining a running freedom for the chains. Since the foot sprockets are normally submerged a substantial distance beneath the surface of the water, it is impractical to rely on a visual inspection to determine when the chains are 3,403,552 Patented Get. 1, 1968 properly seated with the foot sprockets. It has therefore been the normal practice for the operating personnel to apply their skill and judgment in adjusting the chains by the method of trial and error, with the usual result being that the chains are not properly tensioned. Due to the expenses involved in replacing the chains, and since the tension of the screen chains has a direct bearing on the useful life of the chains, it would be desirable to have a relatively inexpensive apparatus which would properly tension the chains to the selected value.

It is therefore a primary object of this invention to provide an apparatus for measuring and selectively adjusting the tension in a chain.

Another object of this invention is to provide a portable chain tension measuring and adjusting apparatus for simultaneously and uniformly adjusting both of the chains supporting the screen trays in a traveling water screen in a manner to obtain the same tension value in each of the chains.

Still another object of this invention is to provide a mechanism for tensioning the chains in a traveling water screen in a positive manner such that the proper tension value will be obtained each time the chains are adjusted without requiring any special skills or judgment by the operating personnel.

A further object of this invention is to provide an apparatus for measuring and selectively adjusting the chains employed in a traveling water screen which is simple to use, rugged and durable in construction, and which may be quickly and easily transported from one traveling water screen to another for tensioning the screen chains associated therewith.

These and other objects and advantages of the invention will be apparent during the course of the following description.

In the accompanying drawings forming a part of this specification and in which like reference characters are employed to designate like parts throughout the same;

FIGURE 1 is a fragmentary side elevational view illustrating the upper end portion of a traveling water screen;

FIGURE 2 is an enlarged fragmentary side elevational view illustrating the placement of the invention relative to the traveling water screen;

FIGURE 3 is a fragmentary sectional view taken on line 33 of FIG. 2;

FIGURE 4 is a schematic view illustrating the fluid pressure control system; and

FIGURE 5 is an enlarged fragmentary side elevational view illustrating another mode of using the invention.

In the drawings, wherein for the purpose of illustration is. shown a preferred embodiment of the invention, and first particularly referring to FIGS. 1 through 3 inclusive, there is illustrated generally the upper end portion of a traveling water screen 11 having the side shown in the figures and an opposite side which is identical in construction to the side shown and described hereinafter. Each side of the traveling water screen 11 includes a side frame 12 which is arranged to support the associated end portion of a horizontal top plate 13 which transversely extends between the opposed side frames. A horizontally extending rectangular beam 14 consisting of a pair of spaced parallel side members 15, a top member 16, and a bottom member 17 is mounted on the top plate 13. A pair of spaced parallelly arranged vertical guide members 18 have their upper end portions secured to the side members 15 and extend downwardly therefrom to be secured to the side frame 12. A bearing block 19 is mounted for vertical slidable movement between the guide members 18 in a manner to rotatably support the associated end portion of a transversely extending horizontal head shaft 20 which extends through the upper portion of the traveling water screen 11 and projects through an opening 21 in the head shaft 20 adjacent the opposed side frames 12 are the two head sprockets 22 which support the upper bights of the associated pair of endless chains 23 trained thereover. The chains 23 define a pair of transversely spaced vertically extending elongated loops having their lower bights trained over a pair of axially spaced foot sprockets, not shown, each of which is vertically aligned with its associated head sprocket 22. The foot sprockets are mounted on a foot shaft, not shown, which is ver tically spaced from the head shaft 20 and is rotatably supported between the bottom end portions of the side frames 12. A plurality of screen trays 24 are connected between the chains 23 in a manner to form an endless moveable screen structure. Movement is imparted to the chains 23 and their associated screen trays 24 by rotatably driving the head shaft 20 in a conventional method which does not form a part of this invention and therefore is not herein described.

The tension in the chains 23 is selectably adjusted by means of raising or lowering the head shaft 20 so as to vary the distance between the head sprockets 22 and the associated foot sprockets, not shown, around which the chains are trained. To effect this adjustment the bearing block 19 is supportedly mounted on the bottom end of a threaded take-up screw 25 which extends vertically upwards therefrom between the guide members 18 and through aligned apertures in the top plate 13 and the rectangular beam 14. The upper end of the take-up screw 25 is fitted with a capstan nut 26 and a Washer 27 which rests on the top member 16 such that the rotation of the capstan nut 26 will serve to either raise or lower both the bearing block 19 and the associated end of the head shaft 20, depending upon the direction of rotation of the capstan nut. A horizontally arranged rectangular lifting plate 28 having an apertured integral boss 29 is supported on the upper end portion of the take-up screw 25 in a position parallel to and intermediate the top member 16 and bottom member 17 of the beam 14, and is secured in a selectable position by being clamped between the

nuts

33 and 34 which are fitted onto the take-up screw immediately above and below the lifting plate. It will be understood, of course, that there is an identical chain take-up mechanism disposed on the opposite side of the traveling water screen 11, and that only the mechanism on one side is illustrated in the figures which accompany this application and which are herein described.

Both ends of the head shaft 20 are simultaneously raised or lowered in a manner to simultaneously apply a uniform tensioning force to each of the chains 23 during the chain adjusting procedure herein described. The vertical adjusting movement of the head shaft 20 is accomplished by means of four hydraulic jacks 35 which are connected in a manner which will be described in conjunction with FIG. 4. Each hydraulic jack 35 includes a cylinder portion 36 with a reciprocating piston member 37 disposed therein for telescopic reciprocal movement with respect thereto. A pair of the hydraulic jacks 35 are used on each side of the traveling water screen 11 in association with each lifting plate'28. As illustrated in FIG. 2, a hydraulic jack 35 is placed on each side of the take-up screw 25 such that the cylinder portions 26 are resting on the bottom member 17. The outer end 38 of each piston member 37 is adapted to operatively engage the lower surface of the lifting plate 28 upon the outward movement of the piston members from their respective cylinder portions 36.

Referring now to FIG. 4, there is schematically illustrated a hydraulic system designed to supply and control the flow of pressurized fluid to the hydraulic jacks 35. The hydraulic system includes a reservoir 41 which is connected by a suitable fluid transmission line 42 to a pump 43 which is equipped with an integral unidirectional valve so as to permit the flow of fluid in one direction only. The pump 43 may be driven by any suitable means,

4 however, due to the portability of this invention a hand operated pump is preferred. A fluid transmission line 44 directs the pressurized fluid from the pump 43 to a fluid pressure gauge 45, and thence through a fluid transmission line 47 to the lines 48 which supply the fluid to the hydraulic jacks 35. The pressure gauge 43 is utilized for indicating the exact pressure applied to the hydraulic jacks 35 which are connected in parallel such that the flow of fluid through the lines 48 and into each of the cylinder portions 36 causes an equal force to be applied to each of the piston members 37. In this manner an equal tensioning force is simultaneously applied to both of the chains 23 so as to effect the uniform tensioning of both chains to the same tension value.

Operation of the apparatus is as follows: a pair of the hydraulic jacks 35 are positioned on the opposite sides of each take-up screw 25 with the cylinder portions 36 resting on the bottom member 17. The lifting plates 28 are then vertically adjusted on the take-up screws 25 by means of the nuts 33 and 34 to the selectable position at which the opposite ends of each lifting plate are in a juxtaposed position with the associated outer ends 38 of the piston members 37 located therebeneath. Operation of the pump 43 forces fluid through the

fluid transmission lines

44, 47, and 48 so as to drive the piston members 37 outwardly from their associated cylinder portions 36 in a manner to operatively engage the outer ends 38 with the lower surface of the associated lifting plates 28 so as to effect the elevation of the lifting plates thereby elevating the head shaft 20 and tensioning the chains 23. The head shaft 20 is raised until the pressure gauge indicates that the force applied by the hydraulic jacks 35 has reached the selected value where it has previously been determined that the chains 23 are tensioned to properly engage the foot sprockets, after which the operation of the pump 43 is stopped so as to temporarily support the head shaft at the desired height. The capstan nuts 26 are then turned down to abut against the top member 16, after which they are further turned down until the pressure gauge 45 shows a slight decrease in fluid pressure which indicates that the capstan nuts are supporting the head shaft 20. This method of adjusting the capstan nuts 26 compensates for any distortion of the beam 14 as the capstan nuts are adjusted to positively maintain the head shaft 20 at the desired height.

After the head shaft 20 is secured in the selected position, the hydraulic jacks 35 may be removed from the traveling water screen 11. This is accomplished by opening a valve 49 which is interposed in the hydraulic system in a manner to permit the piston members 37 to retract into their respective cylinder portions 36. The valve 49 has one end coupled into the fluid transmission line 47 and the other end coupled into the reservoir 41 by means of a fluid transmission line 51 so that opening the valve 49 permits the fluid to flow out from the cylinder portions 36 and return to the reservoir. After the piston members 37 have been withdrawn into their respective cylinder portions 36, the valve 49 is closed and the hydraulic jacks 35 may be removed from the traveling water screen 11 and transported to another traveling water screen.

The hydraulic jacks utilized in the system have been illustrated and described as being single acting, and it will be understood that double acting hydraulic jacks could also be utilized.

Referring now to FIG. 5 there is illustrated another means of mounting the invention on a traveling water screen. It will be once again understood, of course, that there is an identical chain take-up mechanism disposed on the opposite side of the traveling water screen, and therefore only one such mechanism is illustrated and described hereinafter. A plate 54 is mounted on the top member 16 of the rectangular beam 14 and is structurally reinforced by spaced members 55 extending downwardly therefrom and secured to the side members 15 and the top plate 13. The take-up screw 25 extends through an associated aperture in the plate 54, and a nut 46 is fitted thereon so as to abut against the top surface of a washer 57 which in turn rests on the plate. The nut 56 serves the same function as the capstan nut 26 (FIG. 2) described hereinabove. A horizontally extending rectangular lifting plate 58 having an integrally formed apertured boss projecting from the center thereof is supported on the upper end portion of the take-up screw 25 in a position above the support plate 54, and is secured to the take-up screw by being clamped between the nuts 61 and 62 which are fitted onto the take-up screw immediately above and below the lifting plate. Rings 63 are welded onto the lower surface of the opposite end portions of the lifting plate 58, and associated rings 64 are welded in corresponding positions on the top surface of the plate 54. The bottom ends of the cylinder portions 36 are rested within the rings 64 such that upon the actuation of the hydraulic jacks 35 the outer ends 38 of the piston members 37 will be elevated into a position within the rings 63 so as to engage the lower surface of the lifting plate 58. The

rings

63 and 64 insure the proper placement and engagement of the hydraulic jacks 35 while simultaneously acting as safety devices to prevent the horizontal movement of the hydraulic jacks 35 during the chain adjusting procedure. The operation of the hydraulic system is identical to that described hereinabove, and the nuts 56 serve to maintain the head shaft 20 at the adjusted level after the completion of the adjusting procedure.

The arrangement and portability of this invention permits the chain adjusting apparatus to be employed for checking and maintaining the proper tension in the chains on several different traveling water screens since the hydraulic jacks and associated equipment can be readily moved between the different locations.

It is to be understood that the form of this invention herewith shown and described is to be taken as a preferred example of the same, and that various changes in the shape, size, and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

Having thus described the invention, I claim:

1. In combination with an endless tension member trained for movement around a pair of substantially parallel shafts, bearing means supporting one of the shafts, guide means supporting the bearing means for movement toward and away from the other shaft, takeup means associated with the bearing means, and an abutment mounted in a fixed position for engagement by the take-up means so that operation of the latter will effect the movement of the one shaft to adjust the tension in the tension member, the improvement which comprises:

pressure fluid operated means operatively associated with the one shaft to apply a force thereon so as to urge the movement thereof in a direction to adjust the tension in the tension member and to temporarily retain the one shaft in the adjusted position during adjustment of the take-up means to maintain the one shaft in the adjusted position; and

means for indicating the tension in the tension member.

2. The combination described in claim 1 further characterized by the pressure fluid operated means comprising:

a source of pressure fluid;

a chamber supported on the abutment is communication with the source for receiving pressure fluid therefrom; and

a member reciprocally disposed in the chamber and extending therefrom for telescopic movement relative thereto so as to engage the one shaft and exert a force thereon, the magnitude of the force being a function of the fluid pressure in the chamber.

3. The combination described in claim 1 wherein the indicating means comprises a gauge connected to the pressure fluid operated means for measuring the pressure of the fluid therein to indicate the tension in the tension member.

4. The combination described in claim 1 further characterized by the pressure fluid operated means being detachably associated with the one shaft for ready removal therefrom.

5. In combination with a pair of endless tension members trained for movement around opposite end portions of two substantially parallel shafts, bearings rotatably supporting the opposite ends of one of the shafts and movable toward and away from the other shaft, take-up means associated with each bearing and including an abutment mounted in a fixed position so that operation of the take-up means will effect movement of the bearing and the associated end of the one shaft relative to the other shaft so as to adjust the tension in the tension member at the associated end of the one shaft, the improvement which comprises:

pressure fluid operated means operatively associated with each bearing for moving both ends of the one shaft in a direction to simultaneously and uniformly adjust the tension in each of the tension members and to temporarily retain the hearings in the adjusted position during the adjustment of the take-up means to maintain the one shaft in the adjusted position; and

means for indicating the tension in the tenison members.

6. The combination as described in claim 5 further characterized by the indicating means comprising a gauge in fluid communication with the pressure fluid operated means for measuring the pressure of the fluid therein to indicate the tension in the tension members.

7. The combination described in claim 5 further characterized by:

a source of pressure fluid; and

means in fluid communication with the source and each of the pressure fluid operated means for regulating the supply of fluid therebetween so as to supply fluid at a uniform pressure to effect the simultaneous operation of all of the pressure fluid operated means.

8. The combination described in claim 7 further characterized by fluid pressure relief means being in fluid communication with the pressure fluid operated means for relieving the fluid pressure therein.

References Cited UNITED STATES PATENTS 1,323,818 12/1919 Berry 73143 XR 3,004,426 10/1961 Lodyn-ski 73-141 3,082,043 3/1963 Orton 74242.l4 XR 3,098,397 7/1963 Schaefer 74242.l4 3,118,315 1/1964 Loosli 74242.l2

RICHARD C. QUEISSER, Primary Examiner.

D CHARLES A. RUEHL, Assistant Examiner.

Claims

1. IN COMBINATION WITH AN ENDLESS TENSION MEMBER TRAINED FOR MOVEMENT AROUND A PAIR OF SUBSTANTIALLY PARALLEL SHAFTS, BEARING MEANS SUPPORTING ONE OF THE SHAFTS, GUIDE MEANS SUPPORTING THE BEARING MEANS FOR MOVEMENT TOWARD AND AWAY FROM THE OTHER SHAFT, TAKEUP MEANS ASSOCIATED WITH THE BEARING MEANS, AND AN ABUTMENT MOUNTED IN A FIXED POSITION FOR ENGAGEMENT BY THE TAKE-UP MEANS SO THAT OPERATION OF THE LATTER WILL EFFECT THE MOVEMENT OF THE ONE SHAFT TO ADJUST THE TENSION IN THE TENSION MEMBER, THE IMPROVEMENT WHICH COMPRISES: PRESSURE FLUID OPERATED MEANS OPERATIVELY ASSOCIATED WITH THE ONE SHAFT TO APPLY A FORCE THEREON SO AS TO URGE THE MOVEMENT THEREOF IN A DIRECTION TO ADJUST THE TENSION IN THE TENSION MEMBER AND TO TEMPORARILY RETAIN THE ONE SHAFT IN THE ADJUSTED POSITION DURING ADJUSTMENT OF THE TAKE-UP MEANS TO MAINTAIN THE ONE SHAFT IN THE ADJUSTED POSITION; AND MEANS FOR INDICATING THE TENSION IN THE TENSION MEMBER.