US2949763A

US2949763A - Wall facing

Info

Publication number: US2949763A
Application number: US585888A
Authority: US
Inventors: John L Felder
Original assignee: Individual
Current assignee: Individual
Priority date: 1956-05-18
Filing date: 1956-05-18
Publication date: 1960-08-23
Anticipated expiration: 1977-08-23

Description

J. L. FELDER Aug. 23, 390

WALL FACING 5 Sheets-Sheet 1 Filed May 18, 1956 & W0 N w 1 Mm v em A F w M w a .1. L. FELDER WALL FACING Aug. 23, 1960 3 Sheecs-Sheet. 2

Filed May 18, 1956 Aug. 23, 1966) J. L. FELDER WALLFACING 3 Sheets-Sheet 3 Filed May 18, 1956 (/0/7/2 lam Jon Fe/aer INVENTOR.

ATTORNEYJ WALL FACING John L. Felder, R0. Box 8005, San Antonio, Tex. Filed May 18, 1956, Ser. No. 585,888

8 Claims. (Cl. 50-354) This invention relates generally to improvements in weatherproof wall facing; and, more particularly, to masonry wall veneer which is substantially erackproof. In one of its aspects, this invention relates to novel apparatus for use in anchoring and sealing between the individual units of such veneer.

In accordance with time-honored practices, the individual facing units of conventional masonry wall veneer are laid up in courses and separated by joints of rigid, cementitious mortar which extend the length and height of the wall. Normally, stresses and strains are set up in the veneer due to settling of the foundation, temperature and atmospheric changes, and movement of the building wall relative thereto. As a result of the very tight bond between the units and the mortar joints, these forces are transmitted the entire length and height of the wall and almost inevitably cause cracks. These cracks will be found in greater length and frequency along the vertical joints, inasmuch as the horizontal joints are usually longer and the major source of force transmission.

An object of this invention is to provide relatively inexpensive masonry wall veneer which will minimize the effect of these disruptive forces and thus reduce cracks to a minimum.

Another object is to provide veneer of the type described in the foregoing object which is actually easier to apply to a wall than conventional veneer.

A further object is to provide masonry wall veneer having horizontal joints between the facing units which are discontinuous so that when said joints are of a rigid cementitious material, the stresses and strains Will be distributed in small increments along relatively short lengths of the courses.

Still another object is to provide masonry wall veneer which facilitates the application of jointing material to the horizontal spaces between courses of facing units.

A still further object is to provide masonry wall veneer which will permit compensation for irregular heights of facing units and maintain the horizontal joints substantially level.

It is conventional to lay up masonry veneer by anchoring the individual units of each course to a wall in spaced apart relation with respect to one another and staggered with respect to the units of the course above and below. When the facing units have been so arranged, the spaces therebetween are filled with jointin material so that the veneer is weatherproofed.

Another object of this invention is to provide apparatus which avoids the need for temporary spacers and the like commonly used in laying up the facing units of a masonry veneer wall.

A still further object is to provide apparatus for use with a masonry veneer wall of the general character described, which apparatus facilitates handling of the anchor.

Still another object is to provide anchors which, in addition to performing their customary function, will enable States Patent Q i 2,949,763 Patented Aug. 23, 1960 each of the foregoing objects to be carried out in a quick and simple manner.

A still further object is to provide an anchor for holding adjacent facing units of each course against a wall, which anchor will also securely hold a prefabricated joint within the space between such units in a manner to vertically space units of the course above from the course below.

A more particular object is to provide such an anchor which is so constructed as to permit the vertical space to be first filled with a rigid cementitious joint material, and then to permit such material to be removed from the space and the prefabricated joint substituted therefor.

A further object is to provide an anchor for holding adjacent units of each course against the wall in a manner which permits the free runoff of water from the space between such units.

Yet another object is to provide an anchor which may be fabricated in quantity at minimum expense and without wastage of material.

Other objects, advantages and features of this invention will be apparent to one skilled in the art upon a consideration of the written specification, the attached claims and the annexed drawings.

In the drawings, wherein like reference characters are used throughout to designate like parts:

Fig. 1 is a perspective view of adjoining walls of a structure which are in the process of being faced or veneered in accordance with the present invention;

Figs. 2 and 3 are front and side views, respectively, of apparatus comprising an assembly for use in anchoring and sealing the vertical spaces between adjacent facing units of each course of the wall veneer;

Fig. 4 is a partial sectional view of an intermediate portion of the wall veneer, including the assembly of Figs. 2 and 3 and taken substantially along broken line 4-4 of Fig. 1;

Fig. 5 is a partial sectional view of a corner of the wall veneer, as seen substantially along broken line 55 of Fig. 1, and including a slightly difierent form of the assembly of Figs. 2 to 4;

Figs. 6 and 7 are perspective views of two different clusters of facing units which may be used in connection with the Wall facing of the present invention;

Fig. 8 is a plan view of one stage of a preferred method of fabricating the anchor of the apparatus of Figs. 2 and 3;

Fig. 9 is a perspective view of this same anchor upon completion of its fabrication and apart from the prefabricated joint to be held thereby;

Fig. 10 is an elevational view of partially completed wall facing in which the facing units thereof are anchored by a modified type of anchor which is particularly wellsuited for first filling the space between the units anchored thereby with cementitious joint material and then a prefabricated joint of the type shown in the apparatus of Figs. 2 and 3;

Fig. 11 is a sectional view of the Wall facing of Fig. 10, taken substantially along broken line 11-11 of Fig. 10;

Fig. 12 is a plan view illustrating one stage in a preferred method of fabricatin the anchor of Figs. 10 and 11;

Fig. 13 is a perspective view of this modified type of anchor in its final form; and

Figs. 14 and 15 are perspective and side sectional views, respectively, of wall facing constructed in accordance with the present invention, together with apparatus for use in filling the horizontal spaces between units of adjacent courses with jointing material.

The wall facing or veneer of the present invention has the outward appearance of conventional veneer in that it comprises a plurality of horizontally extending and vertically spaced apart courses of facing units, with the units of each course being anchored to a building wall in spaced apart relation to one another and staggered with respect to the units of the course above and below. Also, the facing units are slender, lightweight and of any suitable masonry material, such as fired clay, stone or architectural concrete.

However, in accordance with thepresent invention, the vertical spaces between adjacent facing units of each course of the wall facing are filled with prefabricated joints of flexible material which extend at opposite ends across the horizontal spaces between said course and the courses above and below. The discontinuous horizontal spaces which are formed by these bridging portions of the prefabricated vertical joints may be filled either with additional flexible jointing material or, in the interest of economy, with the conventional cementitious mortar-type joint material. In this manner, the forces caused by stresses and strains upon the wall facing will be distributed or transmitted along the horizontal joints thereof in small increments so that there is considerably less opportunity for such forces to cause cracking, or at least the cracks will be of insignificant size.

For example, a brick wall 30 feet long will contain approximately 45 bricks in each course, so that there are approximately 90 vertical joint contacts on the two sides of the brick which contact the jointing material. Assuming that the stress on the wall facing is such that each contact has to absorb an increment of movement of 0.001 inch in order to relieve same, theoretically the conventional cementitious type horizontal joint will, upon finding a weak place in the wall facing, produce a unitary movement of 90 x 0.001 inches, or a crack approximately wide. Obviously, in accordance with the construction of the present invention, each of these approximately 90 contacts would be permitted to absorb an independent movement of only 0.001 inch.

The vertical joints arranged and constructed as above also serve not only to vertically space the courses apart, but also to compensate for irregularities in the height of the various facing units so that the horizontal joints may be kept substantially level. Thus, it is possible not only to lay the individual facing units up with greater speed and uniformity than has heretofore been possible, but also to compensate for vertical shifting of the units of the diiferent courses relative to one another due to the stresses aforementioned. Still further, it will be understood that the prefabricated vertical joints permit a certain amounts of shifting of the facing units of each course laterally with respect to one another.

With the foregoing in mind, it will be appreciated that the objects of the present invention can be accomplished by means of wall facing in which only the vertical joints are prefabricated and of a flexible material. Inasmuch as this construction is considerably less expensive than one in which all the joints are flexible and prefabricated, it may be preferred. On the other hand, however, the greater flexibility enabled by horizontal as well as vertical flexible joints may dictate against economy and thus be preferred in a particular situation. In any case, the wall veneer of the present invention may be so constructed as to first permit a partial and later a more extensive use of prefabricated flexible joints.

In accordance with other novel aspects of the present invention, the prefabricated flexible joints are held in place in the vertical space between adjacent units of each course by means of anchors which also hold such adjacent units against a wall in properly spaced apart relation to one another. In the application of the veneer to a wall, the opposite ends of the vertical joints of flexible material, which extend into the horizontal spaces between the course held by the anchor and the courses above and below, serve as spacers between these latter two courses as they are laid up. Thus, there is no necessity in the application of the wall facing of the present invention to use temporary spacers and the like.

In order to accomplish the other purposes of the in vention, the anchors are preferably sheet metal andprovided with portions for engaging the opposite ends of the facing units to hold same against the walls. These portions comprise flanges which terminate beneath the upper and lower ends of the prefabricated joint which extends across the horizontal spaces. In one form, the anchor contemplated by the present invention is so constructed as to permit the vertical space between adjacent units of a course to be first filled with a cementitious jointing material and the prefabricated joint later substituted therefor, as previously mentioned. In this form, the anchor is provided with parts integral with the facing unit engaging portions which, during the time the cementitious jointing material is disposed within the vertical spaced, serve to space the course above from the courses held by such anchor.

Turning now to a detailed description of the abovedescribed drawings, there is shown in Fig. 1 the corner of a structure having adjoining

frame walls

20 and 21 secured to vertical supports 22. The outer surfaces of the

walls

20 and 21 are covered with a suitable Waterproofing paper 24, as best shown in Figs. 4 and 5.

The wall veneer of the present invention, which is shown in Fig. 1 to partially cover the outer surfaces of the

building walls

20 and 21, is made up of a plurality of horizontally extending and vertically spaced apart courses of individual facing units 25. As previously mentioned, these units are slender, lightweight and of any suitable masonry material. As is well known in the art, the facing units of each course are spaced apart from one another and staggered with respect to a facing unit of the course above and below. Of course, the lowermost and uppermost courses will be staggered only with respect to the course thereabove and therebelow, respectively. Also, as indicated in Fig. 1, alternate courses include a relatively short facing unit 25a at each corner of the wall.

In accordance with the present invention, the facing units of each course are held against the building wall in properly spaced apart relation with respect to adjacent units of the same course by means of novel apparatus, one form of which is shown in Figs. 2 and 3. This apparatus comprises an assembly including a wall tie or anchor 26 having a web 27 with a tab 28 at its upper end securable to the building wall. For this purpose, the tab is preferably prefabricated with a hole 29 for receiving a nail.

Wings 30 project outwardly from opposite sides of the Web beneath the tab to define a channel therebetween having an open side opposite the web and serving to space the adjacent units apart. Flanges 31 on the wings project outwardly of the channel so as to engage with and hold such adjacent units against the wall. In addition, the wings 30 are provided with parts, such as dimples 33, for gripping and holding a prefabricated joint 32 of flexible material in place for sealing between the adjacent facing units.

The facing units are provided at their opposite end edges with grooves 34 for receiving the flanges 31 of the facing units. As particularly shown in Fig. 5, a groove 34a at a corner facing unit may be curved so as to receive a similarly contoured flange 31a of the anchor 26. Such a construction is necessary for holding the corner facing units against the wall by means of a single anchor between them. In order to permit expansion and contraction of the facing units, as contemplated by this invention, the flanges do not extend all the way into the grooves.

As shown in Figs. 6 and 7, the facing units may be made up in clusters A and B with the grooves preformed therein. It is contemplated that these clusters may comprise a plurality of fired clay facing units having lines of separation therebetween along one pair of opposite edges and clay-bonded to one another along their other opposite edges, in accordance with a process described and claimed in my copending application, Serial No. 573,473, filed March 23, 1956, and entitled, Slender Clay Bricks now abandoned. At the job site, these clusters may be given a sharp blow lengthwise of the lines of separations so as to break the clay-bond. Obviously, it is not essential to the purposes of the present invention that such facing units be formed in accordance with my copending application. However, if so formed, the coreless dies from which the columns of stiff clay are extruded may be provided with beads for cutting the exterior of the column as it is extruded therefrom so as to form the grooves 34 and 34a for the individual facing units, as well as parting slots 34!) for cluster B.

It can be seen from Fig. 6, that cluster A may be made up of five long units of a type predominantly used, while the cluster B which is shown in Fig. 7 may, in addition to comprising three such long units, also include on its top side one long unit having a curved groove 34a particularly adapted for use at a corner of the wall and two short units at opposite sides of parting slots 34b along its bottom, also for use at a corner of the wall veneer. Attention in this respect is invited to Fig. 5 wherein both a long unit having a curved groove and a short unit are shown in operative assembly with one another. In the above manner, all the different types of facing units may be extruded from a die having an opening corresponding in height and width to the clusters of Figs. 6 and 7.

In accordance with another novel concept of the present invention, the prefabricated flexible joint 32 for sealing between adjacent units of all except the uppermost and lowermost courses is of such length and so held by the anchor 26 as to properly space apart the course above and below. More particularly, the upper and lower ends 32:: and 32b, respectively, of the joint extend beyond the Wings 30 and flanges 31 of each anchor so as to bridge the spaces between the upper and lower edges of the facing units held by such anchor and the lower and upper edges of the facing units of the courses above and below, respectively. Thus, the upper and lower ends of the joints may be said to define the opposite ends of the discontinuous horizontal spaces between adjacent courses or, in other words, to provide flexible portions of the horizontal joints extending across the veneer. The tab 28 extends above the upper end 32a of each joint so that access is provided to the nail hole 29 as the anchoring and sealing apparatus is secured to the wall.

In addition to serving as a spacer during laying up of the facing units, the prefabricated joint provides the assembly with a large gripping area which facilitates handling and holding in place as it is nailed to the wall, which would otherwise be difiicult in the case of the anchor alone. Also, the anchor has no ledges adapted to be disposed horizontally of the wall when the anchor is so secured thereto, so that rain water which might otherwise be trapped in the vertical space between adjacent facing units will be permitted to run ofi. As a result, corrosion of the anchor and sediment in the prefabricated joint will be minimized.

The prefabricated flexible joints 32 are preferably formed and tooled into the space between adjacent facing units in accordance with my copending applications, Serial Nos. 511,514, now abandoned and 526,586, now Patent No. 2,916,908, filed May 27, 1955, and August 5, 1955, respectively, and each entitled Prefabricated Joints. As disclosed in these copending applications, the joints comprise a prefabricated mass of loosely meshed fibers, which may either be prelubricated or lubricated on the job site for tooling into a permanently non-brittle weatherproof joint. Alternatively, the joints 32 may be otherwise formed so as to provide the flexibility required for the purposes of the present invention and, at least to a certain degree, a weatherproof seal between adjacent 6 facing units in each course. However, the joints disclosed in my copending applications provide a better seal and more permanent protection against weathering than those common in the art.

It should be understood that the term flexible, as it is applied herein to the prefabricated joint, has reference to the deformability as well as the bending qualities of the material making up the joint. Obviously, while the degree of deformability should be sufiicient to compensate for the relative movement of the rigid parts of the veneer relative to one another, the joint material should be sufficiently stiff as to protect the seal between adjacent units and also serve as a vertical spacer.

As previously mentioned, the discontinuous horizontal spaces, defined above and below by the facing units of adjacent courses and at opposite ends by the bridging portions of the prefabricated flexible joints 32, may either be filled with a flexible jointing material or, if preferred, with the customary rigid cementitious mortar, as indicated by the joints 35 in Fig. 1, to seal between the units of adjacent courses.

Referring now to the manner in which the facing units are laid up on the building wall, and with reference to Fig. 1, each of the anchoring and sealing assemblies for the first or lowermost course are nailed to the building wall in properly spaced apart relation adjacent the bottom of the building wall. As can be seen from the drawings, the prefabricated joints for this course are some what shorter than those of intermediate courses as their lower ends are adapted to terminate substantially flush with the lower edge of the facing units. The facing units of the first course are then laid up against the wall by sliding the grooves thereof vertically over the flanges of the anchors.

When these facing units have been so placed, the upper ends 32a of each of the prefabricated joints therebetween will extend above the upper edge of the facing units a distance which is adapted to vertically space the facing units of the course above. The wings 30 of the anchor, and more particularly the dimples 33, provide a secure grip for holding the prefabricated joints 32 against falling from the space between the units as the latter are laid up on opposite sides of each anchor. Still further, this grip upon opposite sides of the prefabricated joints holds the flexible material thereof in place for tooling as described in the two last-mentioned copending applications.

Additional anchoring and sealing assemblies for the second course are then secured to the wall in staggered relation with respect to those of the first course, with the lower end 32b of each prefabricated joint of said second course resting on top of an intermediate portion of a facing unit of the course below. As the facing units of this second course are allowed to slide downwardly over the flanges of these just-secured anchors, their lower edges will engage the upper ends 32a of the joints of the first course. In this position, the facing units of the second course are properly spaced above the ground level and define a horizontal space above the upper edge of the facing units of the first course. The vertical load of each such facing unit of the second course is thus imposed upon the joint of the first course supporting the unit, from which it is transferred to the building wall through the dimples 33 and nail 29. In this supported position, the units of the second course may be levelled off with one another or otherwise adjusted. Obviously, this same procedure may be followed in laying up the successively higher courses. When all the courses have thus been laid up, the horizontal spaces may be filled, as previously mentioned.

As is conventional in the art, these horizontal joints not only seal between the facing units of adjacent courses, but also provide vertical support for the facing units above them. However, as distinguished from regular masonry construction, wherein the load is transferred to the lowermost joint, the anchors 26 act as foundations by distributing the load along the frame building wall. That is, each of the horizontal joints rests at its opposite ends upon the upper edges of the flanges 30 of the anchors for the facing unit below such joint, whereby the load thereof is transferred to the building wall through the nail 29.

From the foregoing, and assuming that the horizontal spaces are filled with a rigid cementitious mortar, it will be understood that stresses and strains in the wall veneer will be distributed horizontally thereacross in increments which require only small compensation between the rigid cementing material disposed in such spaces and the portions of the facing units 25 to which such material is bonded. Furthermore, during laying up of the facing units, if one is found to be of such height as to project above that of an adjacent unit of the same course, the taller of the units may be forced downwardly by any suitable means so that its upper end is substantially on a level with that of the adjacent units of the same course.

It will also be understood that all of the horizontal spaces except those at the corner of the wall are of substantially the same size. Thus, the horizontal joints may also be conveniently preformed of a flexible material; or, if of a rigid cementitious material, these joints may be applied to the horizontal spaces in an improved manner. With reference to Figs. 14 and 15, the horizontal space 36 may be filled with a rigid cementitious mortar by means of a mortar board 37 having an opening 38 at one end of a width and height corresponding to the standard dimensions of the spaces. For this purpose, the board is held up against the wall with its opening 38 aligned with the space to permit a desired quantity 39 of cementi tious mortar to be pushed from the board through the opening and into the space by means of a blade 40 having a handle 41.

As illustrated in Fig. 8, the anchors 26 are of such construction that they may be stamped as an integral piece and Without wastage of material from a continuous strip 42 of sheet metal. Thus, the tabs 28 and wings 30 of the anchor are of the same height so that alternate anchors may be stamped from the strip in reversed relation to one another. At the same time, of course, the nail hole 29 may be punched in the stamped out portions of the sheet metal which form each anchor.

From a comparison of Figs. 8 and 9, it is apparent that after stamping, the top of the T of each piece may be folded inwardly in substantial alignment with the opposite edges of the stem of the T which forms the tab 28 to form the wings 30. Flanges 31 are then formed upon further folding back of the wings. The dimples 33 may, if desired, be preformed during the stamping process and the Wings 30 sprung outwardly to receive the prefabricated joints 32 therebetween. On the other hand, the prefabricated joints 32 may be first inserted between the channel formed by the wings 30 and the dimples 33 then pressed into the wings for holding the prefabricated joints 32 in place.

The modified form of anchor 43, which is best i1- lustrated in Fig. 13, dilfers from anchor 26 in that it is provided with parts for spacing the units of adjacent courses with respect to one another. These parts preferably comprise flanges 44 formed integrally with the web 47 of the anchor above the upper edge of Wings 45 and below tab 46. These flanges are turned outwardly for disposal in a plane intermediate that of the web 47 and the wings, and preferably at about 45 to the web and wings. As can be seen from Fig. 10, these spacer flanges are of such height as to support the facing unit in the course above those units which are held against the wall by' the anchor. Thus, this modified anchor 43 acts upon each of the three facing units shown in the upper portion of Fig. in that it holds the adjacent units of one course against the wall while supporting a facing unit in vertically spaced relation above the facing units so held.

As previously mentioned, it is contemplated that the cementitious type mortar originally placed within the vertical space between adjacent units of each course held by anchors 43 may later be replaced with a prefabricated joint of flexible material. For this purpose, the modified form of anchor 43' corresponds in other respects to that of the anchor 26, particularly in that it has an open side opposite the channel formed between wings 45 so as to receive the prefabricated joint therebetween. Additionally, the wings 45 of this form of anchor are provided with inwardly projecting dimples 48 for holding a prefabricated joint in place within the channel between the wings.

It will be evident that many of the advantages attendant to the previously described wall veneer will also be possible in connection with wall veneer in which prefabricated flexible joints are held by the anchors 43. This modified form of anchor is also constructed in such a manner that it may be fabricated of an integral piece and without wastage of sheet metal. For this purpose, the flanges 49 on the wings 4-5 are interrupted by slots 50 which permit the flat stamped pieces of strip 51 (see Fig. 12) for forming the anchors 43 to be arranged in alternately reversed fashion, as in the case of the anchor 26. That is, these slots 50 will accommodate in the alternate stamped piece the portion thereof which is to form the spacer flanges 44-. Conversely, the stamped out portions which are to form these spacer flanges will accommodate the cut-out portions 50 in an adjacent stamped piece. Obviously, this slot does not interfere with the holding function of the flange 49 within the grooves 34 of adjacent facing units.

From the foregoing it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the apparatus.

It will be understood that certain features and subcombinations are of utility and may be employed \m'thout reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

The invention having been described, what is claimed 1. Wall facing comprising a plurality of horizontally extending and vertically spaced apart courses of facing units, the adjacent units of each course being anchored to a wall in spaced apart relation to one another and staggered with respect to units of an adjacent course, prefabricated joints of flexible material in the vertical spaces between said adjacent units and extending across the horizontal spaces between the staggered units of adjacent courses so as to divide such horizontal spaces into separate sections, and jointing material filling the separate sections of the horizontal spaces.

2. Wall facing of the character defined in claim 1, wherein the separate sections are of substantially the same size.

3. Wall facing of the character defined in claim 2, wherein the jointing material filling the separate sections is a rigid cementitious motar.

4. Wall facing comprising a plurality of horizontally extending and vertically spaced apart courses of facing units, anchors holding the adjacent units of each course against the wall in spaced apart relation to one another and staggered with respect to units of courses above and below, prefabricated joints of flexible material held by the anchors in the vertical spaces between said adjacent units of each course and extending between units in the courses above and below said course so as to vertically space said course above from the course below and divide the horizontal spaces between units of adjacent courses into separate sections, and jointing material filling the separate sections.

5. Wall facing of the character defined in claim 4, wherein said anchors comprise channel-shaped members including a web secured to the wall and wings on the web between which the prefabricated joints are held.

6. Wall facing of the character defined in claim 4, wherein said anchors include wings holding the prefabricated joints therebetween, and flanges on the wings engaging grooves in the units for holding them against the wall.

7. Wall facing, comprising a plurality of horizontally extending and vertically disposed courses of facing units, the units of each course being staggered with respect to those of the courses above and below, anchors holding the adjacent units of each course against the wall in spaced apart relation to one another and spacing said adjacent units vertically from the staggered unit of a vertically adjacent course, prefabricated joints of flexible material disposed within the vertical spaces between said adjacent units of each course and extending between the staggered units in the courses above and below so as below and divide the horizontal spaces between units of 10 vertically adjacent courses into separate sections, and jointing material filling the separate sections.

8. Wall facing of the character defined in claim 7, wherein each of said anchors is secured to the wall and includes a channel disposed within the vertical space between the adjacent units of each course and having its open side facing away from the wall to receive the prefabricated joint, flanges on the channel received within grooves in the ends of said adjacent units, and additional flanges on said anchors extending into the horizontal space between said adjacent units and the staggered unit of said vertically adjacent course.

References Cited in the file of this patent, UNITED STATES PATENTS 982,015 Olsen Ian. 17, 1911 1,912,972 Coca June 6, 1933 2,073,130 Wallace Mar. 9, 1937 2,073,795 Haugaard Mar. 16, 1937 2,088,625 Wallace Aug. 3, 1937 2,101,612 Dufly Dec. 7, 1937 2,201,129 Weiland May-14, 1940 2,379,179 Petersen June 26, 1945 FOREIGN PATENTS 584,202 Great Britain Ian. 7, 1947