CA2699206C - Screening apparatus - Google Patents

Abstract

A screening apparatus comprising screen decks set on angled support legs moveably mounted within a framework and driven by a single force adjustable link arm that is connected to a cam drive shaft. The RPM, angle of the legs and cam throw are adjustable to provide for gentler or more aggressive reciprocation of the deck. The support legs are at an angle relative to the screen deck when at rest and while working. The angled support legs at the non-drive end are independently adjustable. The drive mechanism is outside mounted. A flywheel can be integrated if needed. The apparatus is designed to aggressively separate various materials and throw the overs off the end of the screen deck. The unit could be powered by a variety of motors and be modified to attach to a variety of construction machinery or function as a stationary unit.

Description

Specification A field of invention The invention relates to screening machines for screening gravel, soil, wood chips, rubber, mining materials and the like. This invention has a screen deck vibrating mechanism that has a simple and effective design.
Background/Specification Existing road- portable, stationary or machine attached commercial material screening equipment is expensive and one stationary model, in particular, does not provide for "overs" or their action is more sifting than aggressive separation.
This invention provides for aggressive separation with impressive production at a lower cost. Maintenance and repair with most existing units is expensive or requires specialized parts. This unit is easy and inexpensive to repair and is designed to be efficient, versatile, cost-effective and meet a need in the market place for less expensive, efficient, smaller scale screening applications.
This invention could also be used for larger scale operations, heavy industry, using appropriately sized moving parts.
It is common for most screening machines to be quite large and expensive to manufacture and maintain. This makes it costly for the small contractor to buy or rent.
In one screener sifter in US Pat. Application publication # US 2005/0274654 A1 there is no provision for the oversized material to move away from the screen deck once the material is screened.
In a rotating drum style screener as the Trommex brand at www.screeningandcrushing.com that is attached to a skid steer or excavator, the drum loading is very awkward because it has a round loading mouth. The main bearing used in these machines is very expensive and costly to replace if worn out.

Most larger screening units use expensive eccentric shafts, counterweights, gear drives, bearings, springs, hydraulic components and diesel engines to drive the unit because they must vibrate a heavy frame box with screens mounted inside.
Some smaller units shake one end of the screen deck up and down but not efficiently as in Hudson brand at www.hudson.com and some Proscreen models at www.omhproscreen.com.
The Reed screeners US Pat. # 4,197,194 have two screen decks but these machines discharge their overs and midsized product from each screen deck onto one pile.
This is inefficient because if the customer wants three products he has to change and remove a screen and run the overs material through the screener again to get three product.
Truck screeners US Pat. # 5273164 have to dump their load somewhere every few loader bucket loads.
I have found that these disadvantages can be overcome by my invention.
The invention is an assembly consisting of a cam shaft driven screen deck supported on angled legs, driven at high R.P.M. at a travelling distance of approximately 3/8 of an inch. The diagonal reciprocating and vibrating motion produced by this assembly results in a highly efficient screening machine rivaling anything in the market particularly in the small to medium business niche and for those who cannot afford expensive rental machines or large machine purchases.
The added benefit of this invention is the environmentally friendly lack of need for hydraulic components, its efficient use of energy, low maintenance and the reasonably priced and easily replaceable, unspecialized, parts.
The unique feature of this invention is that it applies simple forces of physics and mechanical actions, direct drive, that result in a reciprocating, vibrating and forceful diagonal motion unlike the inefficient sifting motion of oscillating machines and solves the problem of removal of overs and multi-product production. It is in a separate category from less effective sifters and from the larger more expensive machines and is in a niche of its own. It is also has multiple uses and is easily adjustable and would meet the needs of a number of businesses.
An objective of this invention is to provide a portable screener, with a stationary option, that is easy to maintain.
Another objective is to provide an apparatus that uses as few moving parts as possible, ie. direct drive, and an effective mechanical action to result in low manufacturing cost.

A further objective is to provide an invention that has inexpensive, readily available maintenance parts that are not specialized.
Another objective is to not use hydraulic components in the stationary machine thus lowering costs and making it better for the environment.
Another objective is to provide ease of adjustment through the link arm adjuster and leg adjustments.
My invention would be useful for many small contractors, farmers, miners, ranchers, manufacturing or material sorting plants because it is affordable, effective and easy to maintain. This invention can be used in several different styles of screening machine configurations using the same screen deck mechanism, for example, as an attachment to a loader or excavator as shown in drawings Fig.10, Fig.11 and Fig.12.
The focus of this invention is a reciprocating screen deck assembly that is set on angled support legs moveably mounted within a framework and driven by a single force adjustable link arm that is connected to a cam drive shaft. The RPM, angle of the legs and cam throw are adjustable. The support legs are at an angle relative to the screen deck when at rest and while working. The angle of the legs on the non-drive end are independently adjustable. When driven back and forth diagonally with a cam drive shaft at the correct speed and distance this results in a very effective and aggressive screening action.
The screen deck itself vibrates, not a heavy box frame as in most other screening machines, thus requiring less energy to operate.
In this stationary unit a simple electric generator or a household source would provide enough electricity to power the electric motor drives. This would reduce operating costs.
In addition to the effectiveness of the screen deck it is also inexpensive to manufacture and simple to maintain, making it a desirable option to what is presently in the market place.
To illustrate the effectiveness of this screening apparatus the test specs.
were done with the deck in a horizontal position. Most screen decks rely on a mid to steep angle to help move the material down the length of the screen deck but this deck does not. The production measured on my prototype was on a 17" wide by 40"long by 3/4" square mesh screen cloth was .44 cubic yards per minute. The material used was standard gravel material and separated into 2 products.

This invention as shown in Figure 1 represents a rock, or similar product, material separation machine. The core of this invention lies in five key aspects:
= First is the angle of the hinged support legs, while at rest and working, in relation to the screen deck. The resulting action when driven at the correct speed allows for material to be separated with relative ease while throwing overs off the end of the deck. The non-drive end legs are independently adjustable.
= Second is the aspect of the single force eccentric cam as shown in figure 2 (17) connected to a single force adjustable link arm. This results in a precise throw that allows for optimal material separation.
= Third is a properly weighted flywheel to dampen vibrations in the screening system, if necessary.
= Fourth is the angle of the screen deck as shown in figure 3, which allows for larger volumes of material to be separated.
= Finally the industrial environment that the invention will be subjected to would be reflected in the materials used to build the device, for example, a large-scale industry or a machine attachment.
The combination of these five factors, as well as the others previously mentioned, are what makes this invention unique and a new design for effective material separation.

Brief description of drawings Figure 1 is a perspective view of 4 screen frames driven by the cam drive shaft assembly Fig. 2 is a close up perspective view of a single adjustable link arm with a keyed eccentric cam placed in the large end Fig. 3 is a perspective side view of a single screen frame and angled support legs Fig. 4 is a side view of 2 screen frames and angled support legs being driven by an electric motor drive assembly Fig. 5 is a close up perspective view of the drive assembly shown in Fig.

showing the bearing mounted keyed cam drive shaft, eccentric cam and link arm Fig. 6 is a perspective view of various sizes of screen cloth installed in the screen frames Fig. 7 is a front perspective view of a portable screening apparatus embodying this invention. The screen cloth is not shown for clarity.
Fig. 8 is a perspective view from the hitch end showing the screening apparatus of Fig. 1 after it has screened the rough material into 3 piles. Fines, underneath the machine, oversized material, left pile, and middle product, under far end of conveyor Fig. 9 is a back perspective view, loading side, showing drive arrangement and various material piles noted in Fig. 8. Material retaining walls and screen cloths are not shown for clarity Fig. 10 is a drawing of a machine portable attachment using the same screening mechanism described in the abstract. The left view shows the drive end with the position of the screen deck with the drive mechanism not shown. Connecting plate is shown where the apparatus would connect to a loader. Right view is a cutaway front view showing the material being screened.
Fig. 11 shows the machine portable attachment digging into an unscreened pile to fill the hopper Fig. 12 shows an upright view of apparatus attached to a loader Drawings which illustrate the embodiments of the invention.
The screener machine drawing Fig. 8 shows the material that has been separated into the various sizes predetermined by the screen mesh sizes chosen.
A The larger, oversized, material vibrates over the top surface of the deck and falls off the end onto a pile (24).
B The material that drops through the top screen deck falls onto the next screen deck and vibrates to the end onto a sideways mounted conveyor moves up the conveyor and drops onto another pile (25). This material we will call the mid sized product.
C The fines material that is small enough to drop through both the screen decks will fall onto the ground below onto a third pile (26).
The operator of the bucket loader would remove the material from these three piles when necessary.

Summary/ Detailed Description In one aspect of the invention, a portable material screening machine comprises of a basically rectangular frame. The screen decks slope gently downward at the discharge end. The top end has angled metal funneling surfaces to direct the material onto the vibrating screen deck surfaces. Rubber dampering blankets may be attached part way down the top deck to slow the flow of material as it travels along the deck toward the discharge end. This prevents rocks bouncing over the deck surface.
In one embodiment of this invention, shown in Fig. 9 in the drawings it shows four separate screen decks (two sets) that are cam driven by the same cam drive shaft.
A sideways conveyor collects and moves middle sized product up the conveyor to a pile. This embodiment would be capable of making three different products.
One aspect of this embodiment shows a moveable set of wheels Fig. 7 , for transport, (7) at the back end of the screening machine.
Another aspect of this embodiment shows a towing hitch for use when moving the screening machine form site to site. Fig. 7 (6) A different but more basic embodiment would have a similar rectangular framework, moveable wheels and tow hitch with two screen decks side by side with no sideways conveyer. The material funneling surfaces would be approximately the same as stated in the first embodiment. This screening machine would be capable of screening two different products.
Shown in Fig. 7 the screening machine has a rectangular box type frame.
The machine has a higher back and sides where the material is dumped onto the screen deck and a slightly lower front side, discharge of material side. The funnel shaped sides Fig. 7 (2,3) direct the material onto the top screen deck surface.
In Fig. 4 the top screen decks, larger mesh, (8A) which separates coarse material is set above the lower screen decks, finer mesh, (86). In Fig. 8 the side ways conveyor (1) is situated to collect and convey middle sized material that has gone over the end of lower deck to a stock pile.

In Fig. 9 the screen decks are situated in frame (4) on angled support legs (9) .
They are slightly narrower than frame (4) to allow back and forth movement when driven by drive assembly.
In Fig. 1 showing 4 screen decks, the cam drive shaft (13) are driven by an electric motor (16), pulley arrangement (15) at approximately 700 to 1100 RPM. This drive arrangement is bolted securely to the frame Fig. 5. The eccentric cam part Fig. 5 (17) is keyed to the cam drive shaft (13) .
In one 360 degree turn the cam moves the 4 link arms Fig. 5 (12) back and forth approximately 3/16 inches to 1/2 inches depending on the eccentric cam the operator has installed on the drive shaft. 3/8 inch throw is standard.
These cams (17) are changeable.
In Fig. 2 the link arm (12) at one end has a nylatron bushing pressed into it (18), width is slightly less than the eccentric cam. At the other end it is pinned (19) to the screen deck. Midway on this link arm is an adjustment nut (27). This adjuster allows the operator to vary the angle of the angled support legs in relation to the screen deck.
In Fig 4 this adjustment would vary the aggressiveness of the screen deck vibration.
In Fig.4 the 2 screen decks on one side of the machine oppose each other 180 degrees in one 360 degree revolution of the drive shaft.
This results in less energy being used to rotate this mechanism because as one screen deck is moving up and forward (diagonally) the other would be moving back and down,diagonally, providing dual use of the energy stroke. See directional arrows (C) in Fig. 4.
In Fig. 4 the screen decks (8A),(813) are mounted on 4 or more angled support legs each one with an end pinned to the screen deck and the other end pinned to the frame. The angle of the support legs to the screen deck is critical. It should be approximately 58 degrees. This is achieved by the length of the link arm Fig.
2.
In Fig. 1 the screen deck frames are constructed of metal or suitable material.
The screen cloth is removable and designed to be clamped securely into the screen frame.

In Fig. 9 the side ways conveyor would also be powered by and electric motor and reducer (16A) to rotate the belt fast enough to carry the middle sized material away.
This conveyor is mounted at a slight incline to allow for the loader person to remove the pile when needed and to provide space for a higher stockpile.
In one aspect of this embodiment the high side is open on the back of the machine see Fig. 9. This rectangular opening between 5A,5B,5C would be approximately 6 feet high and 8 feet wide to allow for ease of movement for the loader operator to retrieve the fines material that has dropped through both screens to the ground below. This rectangular box like area would have metal walls on the front side and side walls to keep all the 3 product sizes separate from each other, not shown for clarity.
In Fig. 7 this embodiment has a set of wheels (7) fixed to one end at the screening machine. These wheels could be moveable up and down. In the up position the frame of the screening machine would rest squarely on the ground. In the transport position the wheels would be lowered and the machine would be raised slightly off the ground.
On the other end the machine would have a trailer hitch secured to it. This would have a jack for raising and lowering this end of the machine to allow for setting the machine on the ground for the screening position or raising it up and setting it on the truck towing hitch for the travel position.
The hitch area would also serve as a place to mount the generator needed for powering the electric motors.
In this embodiment illustrated in Figures 7, 8 and 9 if the operator was making only 2 products they could blank off the lower screen decks thus sending the fines material onto the conveyor and stock piling it instead of it falling to the ground below.
In another embodiment using the same off set cam drive arrangement and the same basic rectangular box type frame there would be one level of screen deck instead of 2 levels as in the previous embodiment. The overs would travel off the end of the screen deck and fall onto the ground. The fines would fall through the screen opening to the ground below. There would be only 2 products made with this arrangement. There would be no side ways conveyor installed on this simple model.
As stated in my Abstract the focus of this invention is a reciprocating screen deck that is supported on angled legs relative to the screen deck. This screen deck system can be placed in a number of screening machine embodiments and in another embodiment there could be a second conveyor under the screen deck catching the fines. This second conveyor could be situated between the transport wheels.

It is understood that the above-described embodiment is merely illustrative of the application. It will be appreciated by those skilled in the arts pertaining thereto, that the present invention can be practiced in various alternate forms, proportion, and configurations and while the invention has been shown and described with reference to a preferred embodiment or embodiments thereof, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (4)

1. A material screening apparatus comprising:
- a main structural frame - a plurality of screen decks moveably secured within said main structural frame - a cam drive shaft assembly linked to said screen decks, configured to provide a reciprocating motion when rotated - a power source to provide movement to said screen decks - said screen deck having a rectangular frame - a removable screen cloth secured within said frame - said screen deck when reciprocated moves in a diagonal motion - a plurality of hinged angled support legs supporting each screen deck from underneath - said support legs moveably fasten the screen deck frame to the main structural frame - said support legs are set at an angle relative to the screen deck while at rest and while working - a means of mechanically connecting said power source to the cam drive shaft assembly

2. The cam drive shaft assembly of claim 1 further comprising:
- said cam drive shaft assembly set in bearings secured to the main structural frame - a flywheel attached to the cam drive shaft assembly - a single force length adjustable link arm connecting said screen deck to the cam drive shaft - a length adjuster located midway on the length adjustable link arm - said length adjuster provides a means for setting support leg angle to achieve optimum screening action

3. The apparatus of claim 1 wherein the power source further comprising:
- said power source comprising an electric, gas, diesel or hydraulic motor - said power source of sufficient size to rotate the cam drive shaft at

4. The apparatus of claim 1 wherein the main structural frame further comprising:
- a stationary embodiment or;
- a mobile machine attachable embodiment