Title:
Variable cam adjustment arrangement
United States Patent 3874327


Abstract:
A control device is provided for use with an apparatus adapted for the disposition of granular material upon a moving sheet of substrate during the manufacture of roofing shingles. The control device comprises a rotatable cam driven by the shingle manufacturing apparatus and having a variable cam surface, a slidable switch adapted to periodically energize an electric clutch to control the disposition of the granular material, said switch having an actuating arm in contact with the cam surface, an electro-pneumatic transducer responsive to the speed of the moving sheet of substrate and adapted to emit an output signal proportional in magnitude to such speed, and a pnuematic cylinder controlled by the output signal of the transducer and having an extendible stem in engagement with the switch to slide said switch along the cam surface in a direction parallel to the axis of rotation of said cam a distance corresponding to the substrate feed speed, and thereby control the position of the switch actuating arm with respect to the variable cam surface to change the duration of the actuation of the switch, so that disposition of the granular material corresponds with the substrate speed.



Inventors:
FURMAN IRVIN
Application Number:
05/317530
Publication Date:
04/01/1975
Filing Date:
12/22/1972
Assignee:
GAF CORPORATION
Primary Class:
Other Classes:
118/308, 222/52
International Classes:
B05C19/06; G05D7/06; (IPC1-7): B05C11/10
Field of Search:
222/52 118
View Patent Images:
US Patent References:
3742899POWDER MARKER1973-07-03Alperin et al.
3737338N/A1973-06-05Kabelitz
3676032N/A1972-07-11Meyer et al.
3595204FLUID APPLICATOR APPARATUS1971-07-27McIntyre et al.
2704530N/A1955-03-22Nilsen et al.



Primary Examiner:
Hoffman, Drayton E.
Assistant Examiner:
Rolla, Joseph J.
Attorney, Agent or Firm:
Kehm, Walter Leavitt Samson C. B.
Claims:
What is claimed

1. A control device for use in conjunction with an asphalt shingle manufacturing device of the type having at least one power driven feed roller for advancing asphalt substrate material, a blender feed roller for depositing granular material on the moving asphalt substrate, and an electric brake clutch for controlling the operation of the blender feed roller, comprising, in combination, a cam operatively connected for rotational movement to the power driven feed roller and having a cam surface which varies in shape across the face thereof; a switch electrically connected to the brake clutch slidably disposed in close juxtaposition to said cam and having an actuating arm in sliding operative contact with the cam surface to periodically energize and de-energize said brake clutch in response to the rotational movement of said cam; pneumatic means having an extendible stem in operative engagement with said switch to move the switch along the cam surface in a direction parallel to the axis of rotation of said cam; and electro-pneumatic transducer means operatively connected to the pneumatic means and responsive to the speed of the asphalt feed roller, adapted to emit an output signal proportional in magnitude to such speed to actuate said pneumatic means to cause the stem thereof to move said switch along the cam surface a distance corresponding to the magnitude of the output signal; said cam surface being shaped such that the duration of each switch actuation increases as the speed of the asphalt feed roller increases.

2. A control apparatus in accordance with claim 1, in which the cam surface includes an indented portion defined by a pair of spaced apart steps extending in an axial direction substantially across the entire face of the cam, at least one of said steps being disposed at an angle with respect to the other of said steps, so that the distance therebetween varies from one end of the cam to the other end of the cam.

3. A control apparatus in accordance with claim 2, in which the relative position of the indented portion of the cam is adjustable.

Description:
The present invention relates to control of apparatus employed in the process of depositing colored ceramic granules onto a moving web. More particularly, the present invention is directed to an apparatus useful to control the operation of a granule blend and feed assembly in the production of asphalt roofing shingles.

In the production of roofing shingle materials, it is essential that the correct blend and mix of granule materials as applied to the asphalt roofing substrate be correctly and uniformly applied so as to avoid any uneven distribution and defects in the final product. In accordance with the present invention a variable cam assembly is provided to control the operation of an electric brake clutch arrangement which is used in conjunction with a blender for depositing the ceramic granules. It is known in the manufacture of granular coated shingles, to employ an apparatus having a hopper through which granules are fed. Such hopper cooperates with a blender feed roller for receiving and thereafter dispensing select amounts of granules on to a moving web of asphalt material. For dispensing correct amounts and colors of such granular material, it is important that a number of operational parameters all be controlled. For example, in order to obtain uniform patterns of distribution, particular care has to be paid to the registration between the sheet travel speed and the flow of such granular material. In this connection, during the operation of blender feed roller, it is known to provide an electric brake clutch to transmit intermittant rotary motion to the blender feed roller and thus control the deposition of the granular material.

In carrying out the above operation, a number of common problems arise, especially as they relate to variations due to clutch and brake slippage, sequencing mechanism variation, and different machine speeds with respect to fixed clutch and brake response times. Accordingly, to overcome these problems it has been common to control the electric clutch brake by means of a switch having an actuating arm in operative engagement with a rotatable cam having a uniformly indented surface portion. The cam is operatively connected for rotatable movement to a feed roller for the asphalt web material, and the switch is adapted to energize the electric clutch brake, and thus impart rotary motion to the granular blender feed roller whenever the actuating arm engages the indented cam surface (ie, the "cam-in" position). This function is quite critical to correct granule disposition. However, it has been found that as higher asphalt feed speeds are used during the production operation, the cam does not adequately compensate for variations in the acceleration and deceleration of the blender feed roll. In this regard, with a continuous acceleration and deceleration of the granular feeding roll, the granules being released are not being deposited evenly on the coated asphalted moving web. As a result, defects in the finished product occur due to a lack of uniformity in granule deposition. With this arrangement, even deposition can only occur when the blender feed roll is rotating at a constant speed so as to overcome any of the aforementioned irregularities.

The problem of uneven and short blend deposition of granular materials at machine speeds in excess of 300 feet a minute of travel (along a substrate upon which the granules are to be deposited) was one that was recognized as something that materially contributed to an unacceptable product. The difficulty arose only at speeds of travel in excess of the aforementioned amount. At lower speeds, the blender, while mixing different colors of granules, did not present any problems. In addition, feed speeds in excess of 500 feet per minute caused the granule drops to become almost obliterated.

The importance of good product quality at high product output speeds is essential to the making of a more efficient and less costly product when compared to comparable product manufactured at lower speeds. The deposition of colored ceramic granules with uniform dispersion, color tone, and physical strength at high speeds is something that the prior art has long sought. Furthermore, since the difference between granule depositions at high and low speeds respectively, of the finished product when installed on a roofing substrate is readily noticeable, obviously, from an aesthetic point of view, a uniform product would tend to have greater sales appeal. Lastly, the previously mentioned problems all tend to increase the cost and labor associated with quality control implementation of the end product.

It has been discovered that the reason for uneven and short drops of granule material at high speeds is due to the inability of electric clutches to overcome the inertia forces necessary to start up the blender feed roll from a zero acceleration position to full machine speed. During this time, the cam switch is not always in the "cam-in" position, that is - the position in which the granule blender roll is engaged so that granular material can be fed from a feed hopper. Therefore, there is an uneven granule feed to the web of substrate material. This occurred because before the feed roll could attain its required speed, the switch for controlling the clutch was already in the "cam-out" position, thus disengaging the clutch and causing incomplete drops of granular material were deposited from the hopper. Furthermore, evenly deposited granule mixtures will only result when the blender feed roll is rotating at a constant speed. Until such constant speeds are attained, it is not possible to predict with any high degree of accuracy the color, form and shape of the ultimate dispersion of granular material on the moving web.

To overcome this problem, the instant invention employs a rotatable cam having a variable cam surface to provide a variable size "cam-in" area, a slidable switch to control the electric clutch having an actuating arm in engagement with the cam surface, an electro-pneumatic transducer responsive to the speed of the asphalt feed roller, and a positioner coupled to the transducer and the switch to slidably move said switch along the cam surface in a direction parallel to the axis of rotation of the cam as the asphalt feed speed fluctuates and thereby control the position of the switch actuating arm with respect to the variable cam surface. In this manner, the "cam-in" time is increased as the machine speed increases to thereby cause longer granule deposition intervals to be produced.

Accordingly, it is the main object of the present invention to obviate the defects of the prior art.

It is still a further object of the present invention to provide an apparatus adapted to function in conjunction with a granular feed assembly for allowing a uniform deposition of granular material upon a web of sheet material at high speeds of travel.

Another object of the present invention is to provide an apparatus adapted to increase the speed of travel by lengthening the "cam-in" time in relation to the machine speed by means of a novel cam configuration.

Still another object of the present invention is to provide a new and novel granule blending apparatus capable of insuring uniform deposition during acceleration and deceleration of the blending roller. In general, the control device of the present invention is adapted for use in conjunction with an asphalt shingle manufacturing apparatus of the type having at least one power driven feed roller for advancing asphalt substrate material, a blender feed roller for depositing granule material on the moving asphalt substrate, and an electric brake clutch for controlling the blender feed roller, and comprises a cam operatively connected for rotational movement to the power driven feed roller and having a cam surface which varies in shape across the face thereof; a slidable switch electrically connected to the brake clutch and having an actuating arm in sliding operative contact with the cam surface to periodically energize and de-energize said brake clutch in response to the rotational movement of said cam; pneumatic means having an extendible stem in operative engagement with said switch to move the switch along the cam surface in a direction parallel to the axis of rotation of the cam; and electro-pneumatic transducer means operatively connected to the pneumatic means and responsive to the speed of the asphalt feed roller and adapted to emit an output signal proportional in magnitude to such speed, to actuate said pneumatic means to cause the stem thereof to move said switch along the cam surface a distance corresponding to the magnitude of the output signal; said cam surface being shaped such that the duration of each switch actuation increases as the speed of the asphalt speed roller increases.

As additional features of the invention, the shape of the cam surface is manually adjustable.

The aforementioned objects will be best understood with respect to the specification, claims and accompanying drawings.

FIG. 1 illustrates a schematic representation of the instant invention.

FIG. 2 illustrates a top elevational view of how the invention can be adjusted.

According to FIG. 1, a rotatable cylindrically shaped cam 1 is employed, the surface 1a of which is adjustable for movement around the periphery of sleeve 2. The cam 1 has an integral drive shaft 10, which is driven mechanically in the direction of the arrow from a feed roller of an asphalt shingle manufacturing apparatus. The cam surface has an indented portion 1a defined by step 4 on cam plate 4a and step 5 on the cam surface, which indented portion varies in size across the face of the cam. The relative position of such indented portion 1a can be adjusted by loosening the bolts 3 shown in FIG. 2 and revolving the cam body on the sleeve 2. In this manner, such indented portion, referred to as the cam-in position, can either be advanced or retarded by 30°. This amount is predesigned into the apparatus consistent with the operating conditions of the granular application process. Other adjustments can be made by removing cam plate 4a or changing the the profile across the step 4 of cam plate 4a and this is shown by the relationship of steps 4 and 5. A switch 6 is in circuit relation with the electric brake clutch (not shown) which controls the operation of the blender feed roller of the asphalt shingle manufacturing apparatus and is adapted to energize and de-energize said clutch.

The switch has an actuating arm 6a in operative sliding contact with the surface of cam 1 and is adapted to activate the switch to energize the clutch upon engagement with the indented surface portion 1a of the cam. (the "cam-in" position). An electro-pneumatic transducer 11 of a conventional type responsive to the feed speed of the asphalt substrate being coated is in circuit relationship with a pneumatic cylinder 7 via an actuator 8 is adapted to impart an input signal thereto, which in turn enables pressurized air from a suitable air supply preferably regulated between 20 psi and 100 psi, to activate the cylinder in direct magnitude proportion to such input signal. The air supplied to the cylinder 7 enters via actuator 8 and as this occurs, an actuator stem 9 of cylinder 7 in operative engagement with a slidable base 12 of switch 6; will slidably move the switch in a direction parallel to the axis of rotation of cam 1, thus varying the point of engagement of arm 6a and the cam surface. As the asphalt sheet feed speed increases, the air pressure fed to cylinder 7 proportionally increases, due to a corresponding increase in the magnitude of the input signal from transducer 11. In this manner, switch 6 is urged along the surface of cam 1. It can be seen that the circumferential length (distance between steps 4 and 5) of the indented cam surface portion 1a increases from right to left along the cam surface, so that the duration of the cam-in time likewise increases as the switch 6 is moved to the left. Thus, the duration of the brake clutch energization increases in proportion to the asphalt substrate feed speed.

By the aforementioned arrangement, it is possible to compensate for the increase in acceleration and deceleration of the blender feed roll especially at large speeds in excess of 300 feet per minute.

As can be understood from the aforementioned, a variable cam angle may be employed especially where the asphalt manufacturing operation requires intermittent feeding or marking by a rotating device as the web is traveling at a varied line of speed of travel.

It will be understood that the foregoing relates to only a preferred embodiment of the invention, and that it is intended to cover all changes and modifications of the invention, which do not constitute departures from the spirit and scope of the invention.