US 3214314 A
Description (OCR text may contain errors)
Oct. 26, 1965 F. w. ROWBOTTAM METHOD FOR SCREEN ASSEMBLY 2 Sheets-Sheet 1 Filed Feb. 12, 1962 INVENTORS. r f 1W7.- M RQWBOTTA BY Mun-x A4 A AKMEY A GENT METHOD FOR SCREEN ASSEMBLY Filed Feb. 12, 1962 2 Sheets-Sheet 2 INVENTORS. k c s M Rom/607741? WALTER fi fi/A/WEV AGE/w" United States Patent 3,214,314 METHOD FOR SCREEN ASSEMBLY Francis W. Rowbottam, Palos Verdes, Calif. (1911 W. 139th St, Garden-a, Calif.) Filed Feb. 12, 1962, Ser. No. 172,499 2 Claims. (Cl. 156160) This invention relates to method and apparatus for screen assembly and is particularly concerned with automated installation of screening upon a frame, it being a general object of this invention to automatically assemble screening upon frames that vary in size and in proportion.
Screening is ordinarily installed by hand upon frames that are designed to maintain said screening in a taut planar condition. In order to properly apply screening to frames a technique must be developed whereby appropriate tautness is achieved, but without distorting the frame. The problem arises in the frailty of the frames which are of light construction and which have a rabbet groove for the reception of a retaining strip or filler that wedges the marginal portion of the screening in said rabbet groove. The filler strip is usually applied with an instrument adapted to apply pressure with experienced manipulation, with the screening beneath the filler strip so as to be pressed into the rabbet groove. In any case, the careful manual application of the filler strip to retain the screen in the rabbet grooves is time-consuming, and the output of a skilled workman is rather limited, the installation of said screening being slow and tedious.
An object of this invention is to receive random sized frames and to install screening thereon without resort to manual labor.
Another object of this invention is to provide an apparatus for the purpose set forth above and which operates continuously and without interruption. That is, the method and apparatus herein disclosed does not intermittently start and stop, and on the contrary it operates at a uniform and continuous rate of speed.
It is an object of this invention to provide a method of assembling screening upon a frame whereby tedious manual operations are eliminated and whereby said screening is anchored by means of a single easily performed step, a step that is readily performed by a ma chine or apparatus, when circumstances require.
It is still another object of this invention to provide a unique method whereby screening is permanently attached to a supporting frame, without the usual tedious time-consuming manipulations that are ordinarily resorted to. With the present invention, two steps characterize the method, namely, (1) to tension the screen in place over a frame, and (2) to fuse the screening to the frame, the only requirement being that fusible materials be involved whereby the screening is fastened to the frame.
The various objects and features of this invention will be fully understood from the following detailed description of the typical preferred form and application thereof, through which description reference is made to the accompanying drawings, in which:
FIG. 1 is a perspective view of a typical screen unit.
FIG. 2 is an enlarged sectional view taken as indicated by line 22 on FIG. 1, and showing the characteristic features of the present invention as initially prepared.
FIG. 3 is a view similar to FIG. 2, and shows the installation thereon of the screening.
FIG. 4 is a schematic plan view of the apparatus provided to carry out the steps of the present invention.
FIGS. 5, 6 and 7 are enlarged sectional views taken substantially as indicated by lines 55, 6--6, and 77 on FIG. 4.
For a proper understanding of this invention it is neces- 3,214,314 Patented Oct. 26, 1965 sary to have in mind the nature of the frame 10 involved and of the finished screen 11 that is produced. The frame 10 is a light weight structure made up of right angularly related rails 12, adjoining in abutted relationship at mitered corners 13. The rails 12 are tubular and formed of sheet metal, and a right angle fitting (not shown) enters abutting rails to join them at said corners, a friction fit being, provided. In order for the rail 12 to receive and retain screening S a rabbet groove 15 is provided at the inner marginal portion of the rail, and in the construction of the groove the sheet metal is overlapped and connected. In making this connection at groove 15, the outer plane of metal is turned to form a complete two-sided channel with a bottom, and the edge plane of metal is turned over the marginal portion of the metal forming the outer side of the channel. In any case, the overlapping of metal occurs at one side wall of the channel, at the inner side thereof, and the edge of the exposed overlap terminates at a downwardly faced step spaced from the bottom of the channel.
With the foregoing usual practice in mind, concerning frame construction, it is usual to force screening S into the channel forming the rabbet groove 15 using a strip or filler, this being a manual operation as hereinabove described. However, with the present invention a strip or filler is not applied as a mechanical key to wedge the screening S in the groove 15. On the contrary, a fusible material F is initially installed in the groove 15, to occupy the same and to be connected by fusion to the screening S. In the preferred form of this invention the fusible material F is vinyl, a plastic material that is readily fused to the material forming the screening S. It is preferred, also, that the screening be made of vinyl, the same plastic material. it is to be understood, however, that a wide range of equivalent materials can be utilized and that it is possible to fuse to or around metal screening S, or other dissimilar materials, using the fusible material F. This invention is characterized by the connection of screening S onto a part of the frame 10, preferably a fusible strip of material F carried by the frame. Although said fusion can be carried out in various ways, it is preferred to employ the direct application of heat, it being understood that chemical action, for example, can be applied, if so desired.
In accordance with the invention, a frame 10 is acquired in assembled condition, having four rails 12 suitably joined and with a body of fusible material F, initially lodged in the rabbet groove 15. Of course, the groove 15 opens in one direction exposing the material F at the face plane of the frame 10, and thus the screening S contacts the said fusible material F when brought into fiat engagement with said face plane of the frame. Said material F is of tubular cross-section so as to be compressed into the groove 15, it has a lip 16 to engage under the edge of metal exposed in the channel groove, and it has a projecting rib 17 to be fused into the mesh of the screening S. As shown, the rib 17 projects from the said face plane of the frame 11.
The method of this invention is practiced by: firstly stretching screening S over the frame 10, and secondly engaging the screening with said fusible material and fusing the same together. Thirdly, the excess screening S outside of the joint made by fusion is eliminated by trimming with a sharp cutting instrument.
The first step of the method involves stretching of the screening S in a manner to maintain a flat plane thereof, and this requires the engagement of opposite marginal edges of the screening and pulling the same taut. It is usually sufficient to tension the screen from two opposite edges, and in extreme circumstances, as with large screens 11, it is feasible to tension the screen from all four edges. In any case, it is required that the screening S be at least 3 coextensive with the frame 10, and by this it is meant that the margins of the screening 3 overlie the fusible material F to which it is to be attached.
The second step of the method involves bringing of the screening S into engagement with the fusible material F and fusing the same together. In practice, heat is the preferred means of causing the desired fusion, and there are various ways and means suitable for the application of said heat. For example, heat lamps, electronic heat generation or heat applicating irons are all feasible. Since the least complicated is the latter, the ironing means is preferable and is shown in the form of invention illustrated. Thus, a heated iron element 18 is placed in contact with the screening S at the fusible material F, and one or both (5 and/or F) are fused into engagement. Said ironing element 18 can be manipulated or mechanically controlled to press against the parts to be joined and to contact, wipe or roll over them, as circumstances require.
As a result of the two simple steps above described, and as they are applied to the particular elements involved, a piece of screening S is readily applied to and fastened securely on a frame It), with the screening tensioned but not in excess, all without undue strain on the frame. Further, the installation of the screening is done in one movement of attachment, said heat being applicable to the entire screen at one short time interval, for example, during but a fraction of a second.
Apparatus is provided to carry out the method hereinabove disclosed, whereby a continuous mechanized production of screens 11 is obtained. As shown in the drawings, the apparatus involves, generally, a frame feeder A, a screening feeder B, a conveyor C, a fusing means D, a trimming means E, and cutting means K. The means A through K are supported on a base indicated in the drawings shown as 20 and interrelated as later described. In order to carry out the method involved; the means A- supplies random sized and/or various shaped frames, the means B supplies screening S in a taut and continuous manner, the conveyor C operates to move the frames 10 with screening S thereon, the fusing means D operates to attach the screening S to the frames 10, the trimming means E operates to dress the final product in the form of a screen, and the cutting means K operates to sever the screens from the supply of screening.
The frame feeder A that supplies all sizes and forms of frames 10 is not limited to any particular dimension of frame and it is such as to deliver any size frame 10, within limits and one at a time. The feeder A involves a conveyer supported stack or supply 21 of frames 10, and it involves right angularly related fences 22 and 23 to place a given corner of each of the frames being handled. The fences 22 and 23 are spaced above the supporting surface of a table 24-, so as to permit delivery of one frame at a time, in a lateral direction parallel to one of the said fences. In order to deliver the frames 10 there is a drive motor 25 that operates chains 26, and a cleat 27 extends between the chains 26 to engage and move each successive lowermost frame 10. The two chains 26 move together, between spaced shafts, to maintain alignment of the cleat 27. The motor 25 operates through a slip clutch 28 so that the frame being delivered can be held in pressured engagement with a stop rail 29. Then, as soon as each frame is removed from said pressured engagement between cleat 27 and stop rail 29, the chains are free to deliver the next successive frame 10.
The screening feeder B that continuously supplies taut screening 5 involves two pairs of screen driving rollers -31 and 32-33. The rollers 30-31 receive screening S therebetween from a roll R thereof, with means such as spring means to pressure the rollers into driving engagement with the screening S. The rollers 32-33 are spaced from the rollers 39-31 a distance substantially greater than the largest screen dimension to be handled, with a spring means to pressure the rollers into driving engagement with the screen S and frame therebetween. In carrying out the invention, the rollers 32-33 are driven somewhat faster than the rollers 30-31, whereby the screening S is pulled taut between the said rollers.
In accordance with the invention, the frame feeder A delivers frames It) intermittently and one at a time in a direction transversely of the screening feeder B and intermediate the two pairs of driving rollers 30-31 and 32-33. As shown, the feeder A is at one side of the feeder B and with the stop rail 29 at the opposite side of the feeder B. Thus, the frames 10 are stopped in pressured engagement with the rail 29 at the said opposite side of the feeder B.
The conveyer C that moves the frames 10 with screening thereon is incorporated in the lowermost rollers 30 and 32, there being a belt 35 extending over these rollers. The belt 35 is rather narrow and located adjacent the stop rail 29. The top section of belt 35 is in a plane to slidably receive and then support the frames 10 delivered by the feeder A, and it operates continuously to deliver frames with screening S superimposed thereon, issuing from the rollers 32-33.
As clearly shown, the roll R of screening S is sufficiently Wide to include all screen frames 10 to be handled, that is, to overlie the material F of said frames.
The fusing means D that attaches the screening S to the frames 10 is incorporated in the uppermost roller 33, and the roller 33 is therefore a heated roller that is thermostatically controlled. Thus, as the frames lt) pass between the rollers 32-33 pressure is applied and heat is absorbed into the metal frames 10 from the roller 33. As a result of this heat transfer there is the presence of heat to fuse the material F into the screening S, or vice versa, as the case may be. Thus, every part of the frames 10 passing between the rollers 32-33 is affected, so that both transverse and longitudinal joinders are made.
The trimming means E that dresses the final product, screens 11, is adapted to sever excess marginal portions of screening from the frames 19. Although the cutter means K operates within the functions of the trimming means E, said means B will be first described. Note that two pairs of parallel and right angularly related margins of screening S must be trimmed from each of the rectangular frames 10 handled by the apparatus. In practice, this trimming is done just outside of the line of joinder, as clearly indicated in FIG. 3 of the drawings. As shown in FIG. 4 there is a pair of right angularly related shafts 36 and 36 carrying cutters 37-37a and 3838t1, respectively. The cutter 3'7 follows the rollers 32-33 and is substantially aligned with the stop rail 29, so as to press onto the frame It at the line indicated in FIG. 3. The cutter 37a is slidably carried on shaft 35 and is positioned therealong by means of a cam-shaped feeler 39 that engages the edge of frame 16 opposite and parallel with the edge guided by stop rail 29. A spring means 40 yieldingly urges the feeler 39 into said engagement, whereby the cutter 37a is aligned so as to press onto the frame 10 at the line indicated in FIG. 3.
A continuation of the conveyor C follows the cutters 37 and 37a, there being a pair of driving guide rollers 4-1-42 to receive the screens and move them forwardly through the cutter means K later described. Said continuation of the conveyor C comprises spaced rolls 43 and 44 with a belt operating thereon to support and move the frames with screening. In order to establish transverse right angular movement of screens, a transversely moving stop 50 is provided and which comprises a pair of transversely spaced rolls 48 and 49 with a drive belt 51 therebetween. The belt 51 can be provided with cleats, or the like, for suflicient frictional engagement with the forwardmost rail of the advancing frame 10, to move the screen frames laterally. In order to trim the remaining margins of the screening S, drive rollers 52-53 are provided to receive the laterally moved frames with the screening thereon. The rollers 52-53 are placed at the side of the conveyor C opposite the stop rail 29 and parallel thereto.
The cutter 38 follows the rollers 52-53 and is substantially aligned with the stop 50 that moves, so as to press onto the frames at the line indicated in FIG. 3. The cutter 38a is slidably carried on shaft 36 and is positioned therealong by means of a cam-shaped feeler 54 that engages the edge of the frames 10 opposite and parallel to the stop 50. A spring means 55 yieldingly urges the feeler 54 into engagement with the frame, whereby the cutter 38a is aligned so as to press onto the frame 10 at the line indicated in FIG. 3.
The cutting means K that severs the frames 10 with screening S thereon from the supply roll R is preferably a shears located intermediate the right angularly related trimming functions of the previously described means E. As shown, the cutting means K follows the cutters 37-37a just ahead of the continuation of the conveyor C, and it is adapted to slice through the screening S following passage therethrough of the frames 10. An electrical switch 56 is indicated and which electrically controls operation of the cutter K. Thus, each time a frame 10 passes the cutter means K a slicing operation is performed, thereby severing the frames 10 from the supply roll R. The frames 10 with screening S thereon are then free to be moved laterally for the remainder of the trimming operation.
From the foregoing it will be seen that the method herein disclosed can be performed manually or by an apparatus such as is shown. The feasibility of the method is inherent in either case and is such as to eliminate the tedious manual application of a wedging strip into the rabbet groove. It is clear that this invention deviates from the usual practice by employing material, fusible material, initially installed in the rails, and said installation of fusible material is readily performed by automated processes, not shown. It will be apparent that suitable drive means can be provided to rotate the chains, rolls, rollers, and various gearing hereinabove described, and in a synchronous manner whereby the apparatus operates in unison. As a result, random sized frames, rectangular in form, are handled entirely without manipulation during the process involved, namely, the installation of screening S upon frames 10 and including the removal of excess marginal portions of screening S.
Having described only a typical preferred form and application of my invention, I do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to myself any modifications or variations that may appear to those skilled in the art and fall within the scope of the following claims.
Having described my invention, I claim:
1. A method of making screens, that includes:
providing a frame having contiguous rails, one face of said rails having a groove;
applying a fusible strip into each of said grooves;
holding screening material tensioned in a plane parallel with the plane of said one face of said rails, the tensioning force being applied from points outside the margins of said frame;
engaging said screening material with said fusible strip material while said screening material. is so tensioned; fusing said screening material to said fusible strip while said screening is so tensioned;
and thereafter trimming said screening material to the marginal portions of said groove.
2. The method of claim 1 wherein heat is applied to fuse said strip with said screening.
References Cited by the Examiner UNITED STATES PATENTS 1,198,134 9/ 16 Kercher 29447 1,714,468 5/29 Espenschied -109 2,316,526 4/43 McDonald 371 2,342,025 2/ 44 Watter 29-447 2,343,037 2/44 Adelman 161-44 2,471,612 5/49 Freeman 156-273 2,514,920 7/50 Wright 160-371 2,638,131 5/53 Rohs 140-409 2,649,392 8/53 Marshall 156-306 2,832,407 4/58 Tracy 160-371 2,886,481 5/59 Swan 160-354 3,005,483 10/61 Middents et al 156583 3,107,991 10/63 Taussig 160-371 EARL M. BERGERT, Primary Examiner.
NED BERGER, Examiner.