US2322377A

US2322377A - Door

Info

Publication number: US2322377A
Application number: US402739A
Authority: US
Inventors: Mcharg Leslie
Original assignee: Individual
Current assignee: Individual
Priority date: 1941-07-17
Filing date: 1941-07-17
Publication date: 1943-06-22
Anticipated expiration: 1960-06-22

Description

June 272, 1943.

L, McHARG DooR- FiledJuly 17, 1941 3 Sheets-Sheet 1 INVENTOR sauf cf/@e6 www@ ATTORNEYS June 22, 1943.y "L, MCHARG i 2,322,377

INVENTOR 605 /c//ezs ATTORNEYS L. MCHARG June 22, 1943.

Doo

Filed July 17, 1941 y3 Sheets-Sheet 3 Patented June 22, 1943 UNITED STATES PATENT OFFICE DOOR Leslie McHarg, Huntington, N. Y.

Application July 17, 1941, Serial No. 402,739

21 Claims.

' The invention relates to a door which is particularly suited for buildings requiring large size doors such as aeroplane hangars. The door is of the type which moves vertically and swings to a horizontal or substantially horizontal position with a portion thereof projecting outside of the doorway.

Itis an object of the invention to construct a door, of the type which moves vertically and swings to a generally horizontal position, which is braced by new and novel means to resist wind pressure thereupon.

Another object of the invention is to construct 'a door, of the type which moves vertically and swings to a generally horizontal position, which is braced to resist wind pressure and which bracing means is rigid and permanently attached to the door and continues to brace the door throughout its opening movement.

Another object of the invention is to construct a sectional door, of the type which moves vertically and swings horizontally, having a new and novel construction for accommodating the operating means for opening andclosing the door.

vAnother object is to construct a sectional door, of the type which raisesvertically and swings to a generally horizontal position, in which each section of the door is uniformly counterbalanced at predetermined distances throughout the length thereof, thereby improving the counterbalancing of the sections when in raised and horizontal position.

Another object is to construct a doorv of the vertical raising and swinging type which is braced against wind pressure and the bracing means is effective during the raising of the door, .and the point of attachment of the operating means to the sections moves in a vertical plane.

A still further object is to construct a slotted door or section of a door. l d Other objects of the invention will be more apparent from the following description taken in connection with the accompanying drawings, illustrating a preferred embodiment of the invention, in which:

Figure 1 is a sectional View of the door showing the sections thereof, the bracing means and other details of construction. ,Y

Figure 2 is an enlarged isometric View of a part of the upper section of the door showing the bracket therefor to which the operating means is attached.

Figure 3 is an enlarged isometric view of a part of the two sections ofl the vdoor showing the mounting of the lower section with relation to the upper section.

Figure 4 is an enlarged isometric View of a part of the lower section of the door showing the channel construction and the bracket carried thereby to which the operating means is attached.

Figure 5 is a sectional view extending vertically through the door showing the two sections in parallel overlapping relation.

Figure 6 is a sectional view through the door showing the two sections in overlapping relation and swung to a horizontal or generally horizontal position.

Figure '7 is an elevational view of the inside face of the door and shows the operating means for the door and its connections with the sections thereof.

The door of the invention is particularly suited for the doors of aeroplane hangars because in these buildings the doors are of great width or length. These doors present such a wide expanse to any wind pressure that eiective bracing of the same constitutes an important problem. The door of the invention is adequately braced against wind pressure throughout the opening movement and withal is earily opened and opens substantially the complete door opening. Also, the construction provides simple counterbalancing means for both sections when in overlapping or side by side relation and when in horizontal position. With the construction of the invention, the hangar framework is subjected only to the weight of the door.

The door is shown mounted in a doorway or door opening I0 in a hangar, only part of which is shown. The hangar has the customary frame or trusses il to support the roof and the lintel of the hangar doorway.

The door illustrated is a sectional style of door having a plurality of sections. In the illustrated embodiment, the door comprises two sections, an upper section I4 and a lower section l5, which are retained together in a suitable fashion so that they can be moved to side by side relation.

The sections particularly shown have means connecting the same together so that the lower section moves upwardly parallel to or in front of the face of the upper section until thetwo sections are in overlapping relation.

The means connecting the two sections together includes an I-beam l1 carried by one of the sections of the door, such as the upper section I4, which I-beam projects substantially beyond the face of the door. The I-beam also projects below the bottom of the section. The other or lower section i5 carri-es a pair of spaced channels i8 which embrace or surround the projecting end of the I-beam. The spaced channels extend above the top of the lower section. One of the purposes of the construction is to provide a slot upon one face of the section into which the I-beam projects.

Suitable roller means are carried by the spaced channels IB and the I-beam l1 to guide the sections !4 and l5 in their relative overlapping movement and to retain the two sections in parallel relation. The means comprises a pair of rollers i9, each carried upon a pin 49 secured to each channel adjacent the upper end thereof, which rollers ride between the ange of the I- beam and a flange 2i) suitably secured, such as by welding, to the web of the I-beam. A second pair of like rollers 2|, each mounted upon a similar pin carried upon each side of the web of the I-beam, ride in a groove formed between the inner flange of the channel and a flange 26 suitably secured the web of each channel I8. Any suitable means for retaining the sections together and permitting one to move to side by side relation, or particularly to overlapping relation, is contemplated. The spaced channels i8 form a slot 22 on one face of the lower door section l5 through which the web of the I-beam il, carried by the upper section I4, passes. The channels are rigidly secured together for approximately half the section height, such as by a plate 23,in order to form a single door section extending the whole width or length of the hangar door openingl or some portion thereof. The space'between the channels on the outside'forms a slot 25 for a purpo-se to be explained hereinafter. This slot preferably is covered by weatherstripping of any suitable kind, that particularly illustrated being doubled rubber strips 24 secured to the ange of each channel and abutting each other at the center. This weatherstripping normally closes the-slot against the weather, yet permits move- 'ment of a part Within the slot by the abutting rubber strips ilexing away. f

The upper section i4 ofthe door has at least one-bracing means located intermediate the ends of the doors and preferably a plurality thereof are provided spaced apart a predetermined distance throughout the length of the door. The bracing means particularly illustrated includes a rigid bar 2l having one end pivoted upon a pin 29 to a roof truss or to a bracket Y28 carried thereby, so that this end of the bar 0r bracing means is approximately at the level of the top ofY the door. The other end of the bar is pivoted to the door, or if it is a sectional door 'to the upper section thereof, upon a pin 30 carried by a bracket '3i carried by the vdoor or upper section thereof. The bracing means is attached to the doorrat, or at a point below, the horizontal center line of the section or door or below the horizontal axis of the center of gravity thereof. Since the bar or bracing means 27 is rigid between its pivot points, that is, Vthe pin V29 by ticularly illustrated includes a weight 34 which is operatively connected to each section by means of cables, each cable 35 for the lower section I5 passing over a pulley 35 carried by the frame of the hangar and being pivotally attached to a bracket 35 secured to the front of the lower section and particularly to one of the channels I8. Obviously, the cable may be connected to any part of the channel structure formed by the pair of spaced channels.

Each counterweight cable 31 for the upper seciion I4 passes over a pulley 40 carried above the door and may be pivotally secured to a bracket 39 carried by each I-beam il forming part of the upper section. The bracket 38 is in line with the slot 25 between the spaced channels I8 and passes between the weatherstripping 24 when the lower section is moved into side by side relation with the upper section 4or particularly raised into overlapping relation therewith. In other words, with the slotted section, the counterbalancng means for each section may be attached to its respective section in or approximately in the same location which simplifies the counterbalancing construction.

The counterbalancing means preferably is of the differential type in which the cables 35vfor the lower section may be brought together to cable 55, and the cables 31 for the upper -section may be brought together to a cable 5G. The cables 54 and 55 are one cable, but by virtue of the pulley 5l', they differentially mount the weight 34, as will appear more fully hereinafter. The pulley system for the cables is to enable the cables to be of the same length.

The operating means also includes power means to raise the lower section I5 into side by side or overlapping relation with the upper section I.4 until the

brackets

35 and 38 are in alignment or substantial alignment and thereafter moves the two sections vertically together. This may be accomplished by any suitable means and in any desirable manner, such as by a stop carried by one of the sections which engages a part of the other section to move the two sections together as a unit. The means illustrated includes a bracket or stop 4|, carried adjacent the bottom and on the inner face of the lower section, which engages the bottom of the upper section so that any further vertical movement carries both sec- `tions together in overlapped relation. The power means to operate the door preferably functions through the counterbalancing means and may comprise a drive means 52, Figure '7, which is driven by a motor or other suitable means. In the construction shown, one end of the cable 54 is wound around the drum 53 and attached thereto, and the end of the cable 55, which is attached to the lower section, has its end attached to the drum so that as cable 54 unwinds from the drum, the other cable 55 winds up thereupon. This construction prevents cable slippage which may result if only one cable were used. When the sections are in overlapping relation and both sec tions are raised vertically and swing horizontally, both cables 54 and 56 move downwardly.

When the lower section alone is moving upwardly into overlapping relation with the upper section, `the cable 54 alone moves downwardly. Because of the pulley 5l, half of the mass of the weight 34 is effective. When, however, both sections of the door move together and both vcables 54 and 55 move downwardly, then each cable transmits half of the pull -of the weight to its respective section. The system has, therefore, a differential effect.

^ Means or mechanism are provided to swing the upper end of the door in a generally horizontal direction during the continued upward movement of both sections, as shown in Figure 6. With the two sections in overlapping relation as shown in Figure 5, the upper ends of both sections are swung to a generally horizontal position. Preferably the upper ends of the two sections o-f the door swing inwardly. Any suitable means may be utilized to accomplish the swinging movement, the means shown being a cam 42 which is fixed 'to the roof frame Il and a roller 43 preferably carried by the upper section is guided thereby.

.The cam has a form so that as the bracing means or bar 21 swingsthe lower portion of the sections outwardly, the upper section is swung inwardly .in such a fashion that the cables 35 and v3l and .their point of attachment to the

brackets

36 and 38 continue to move in a vertical or substantially vertical plane. With this construction, the cables for` the operating means for the door mayY be mounted upon relatively narrow pulleys since the cables remain in a vertical orsubstantially verti- Ycal plane throughout the door opening movesection, raises both sections and swings them to a generally horizontal position. This means includes the operating means, bracing means and the means for controlling the top of the door. 'Ihe vertical slot means is provided in at least one of the door sections to enable a part of the door opening and swinging means or mechanism, which is attached to a center portion of a section between the vertical edges thereof, to pass between the slot when the sections are moving into overlapping relation.

Means may be provided, if desired, to lock the upper edge of the upper section in vertical or closed position. The means may comprise a shoulder 45 which is carried by the truss or frame Il of the hangar and a roller 46 carried upon an arm 4T which is pivoted upon a pin v48 carried `by the upper portion of the upper section. When the upper section is in vertical position, the roller rests behind the shoulder 45 and prevents inward 'movement of the upper edge of the door or section. The roller may be manually lifted or released when it is desired to swing the upper Asection to the top of the doorway, or it may be released automatically by a part of the lower section, such as by the projection 51 upon the --end of the channel structure I8 engaging the lever or arm when the lower section is in itsuppermost overlapping position with respect to the -upper section. y

Although the door particularly illustrated is a two-section door, it is clear that the upper section by itself constitutes a door and may be used as a complete door with the bracing means and` ...The invention is presented to ll a need for improvements in aI door.

It is understood that various modificationsY in structure, as well as changes inmode. of operation, assembly, and

manner of use, may and often do occur to those skilled in the art,. especially after benetingfrom .the .teachings `vof. an. invention. Hence, .it .will be understood that this disclosure is illustrative of preferred means of embodying the invention in useful form by explaining the construction, operation and advantages thereof.

What is claimed is:

1. A door combination for a vertically opening door comprising a door, bracing means pivoted at a xed point spaced from the plane of the door and in the neighborhood of the level of the top of the door and pivoted to the door at the center portion thereof, the bracing means being rigid between its pivot points throughout the movement of the door, means to open and close the door vertically and attached thereto in the horizontal center portion of the door and above the point of attachment of the bracing 'means to the door, and means to guide the upper edge of the door in a generally horizontal direction.

2. A door combination for a vertically opening door comprising a door, bracing means pivoted at a point spaced from the plane of the door and in the neighborhood of the level of the top of the do-or and pivoted to the door below the center thereof, the bracing means being rigid between its pivot points throughout the movement of the door, means to open and close the door and attached to the door approximately at the horizontal axis of the center of gravity thereoi' and abo-ve the point of attachment of the bracing means to the door, and means to guide the upper end of the door inwardly.

3. A door combination for a vertically opening door comprising a door, bracing means pivoted at a point spaced from the plane of the door and in the neighborhood of the level of the top of the door and pivoted to the door at the center portion thereof, the bracing means being rigid between its pivot points throughout the movement of the door, operating means to open and close the door vertically and attached thereto in the horizontal center portion of the door and above the point of attachment of the bracing means to the door, and cam means to guide the upper end of the door inwardly and having a form to maintain the point of attachment of the operating means to the door in a vertical plane as the door moves upwardly and swings toward a horizontal position under the influence of the bracing means and the cam means.

4. A door combination for a vertically opening door comprising a sectional door having at least one lower section and an upper section, -means to retain the sections together and permitting movement of the' sections into side by side relation, bracing means pivoted at a point spaced from the plane of the door and in the neighborhood of the level of the top of the door and pivoted to the upper section at the center portion thereof, the bracing means being rigid between its pivot points throughout the movement of the door, means to operate the door to bring the lower sections into side by side relation with the upper section and raise all sections towards the top of the doorway and to close the doory and means to guide the sections in a generally horizontal direction.

5. A door combination for a vertically opening door comprising a sectional door having a lower section and an upper section, means to retain the sections together and permitting movement of the two sections into side by side relation, bracing means pivoted at a point spaced from the plane of the doo-r and in the neighborhood of the level of the top of the door and piv- .otedto the upper section below the center thereof,

the bracing means being rigid between its pivot points throughout the movement of the door, means attached to the lower section of the door in the center portion thereof to pull the lower section into side by side relation with the upper section and raise both sections toward the top `of the doorwa and means to guide the upper end of the upper section in a general horizontal direction thereby swinging both sections towards a horizontal position.

6. A door combination for a vertically opening door comprising a sectional door having a lower section and an upper section, means to retain the sections together and permitting movement of the two sections into side by side relation, bracing means pivoted at a point spaced from the plane of the door and in the neighborhood of the level of the top of the door and pivoted to Ithe upper section at the center portion thereof,

v the bracing means being rigid. between the pivot points throughout the movement of the door, operating means attached to the lower section of the door approximately upon the horizontal axis `of the center of gravity thereof, means to operate the door to bring the lower section into side by side relation with the upper section and raise both sections towards the top of the doorway, and. means to guide the upper end of the upper section in a general horizontal direction and thereby carry the lower sections therewith.

7. A door combination for a vertically opening door comprising a sectional door having at least one lower section and an upper section, means to retain the sections together and permitting movement of the sections into side by said relation, bracing means pivoted at a point spaced from the plane of the door and in the neighborhood of' the level o-f the top of the door and pivoted to the upper section below the center thereof, the bracing means being rigid between its pivot points throughout the movement of the upper section, means attached to each section cf the door between the vertical edges thereof and approximately upon the horizonal axis of the center of gravity thereof to operate the door to bring the lower sections into side by side relation with the upper section and raise all sections towards the top of the doorway, a vertical slot in at least the lower section extending approximately half Ythe height of the section to permit the next aforesaid means to' pass therethrough when the sections are raised, and means to guide the upper end. of the sections when in side by side relation in a generally horizontal direction.

8. A door combination for a vertically openingv door comprising a sectional door having at least one lower section and an upper section; means vto retain the two sections together and permitting parallel movement of the lower sections into overlapping relation; door raising and swinging means including bracing means pivoted at a point spaced from the plane of the door and in the neighborhood of the level of the top of the door and pivoted to the upper section below the center thereof, the bracing means being rigid between its pivot points throughout the movement of the upper section, means attached to each section of the door between the vertical edges thereof and approximately upon the horizontal axis of the center of gravity thereof to operate the door to bring the lower sections into overlapping relation with the upper section and raise all sections towards the top of the doorway. and mechanism to guide the upper end of the overlapping sections in a generally horizontal direction; and vertical slot means in at least the lower section extending from the top edge thereof approximately half the height of the section to permit one of the means of the door raising and swinging means to pass therethrough when the sections are raised.

9. A door combination for a vertically opening door comprising a sectional door having at least one lower section and an upper section, means to retain the two sections together and permitting parallel movement of the lower Secltions into overlapping relation, bracing means pivoted at a point spaced from the plane of the door and in the neighborhood of the level of the top of the door and pivoted to the upper section below the center thereof, the bracing means being rigid between its pivot points throughout the movement of the upper section, means attached to each section of the door between the vertical edges thereof and approximately upon the horizontal axis of the center oi gravity thereof to operate the door to bring the lower sections into overlapping relation with the upper section and raise all sections towards the top of the doorway, a vertical slot in at least the lower section extending from the top edge thereof approximately half the height of the section to permit the next aforesaid means to pass therethrough when the sections are raised, and means to guide the upper end of the overlapping sections in a general horizontal direction.

10. A door combination for a vertically opening door comprising a sectional door having a lower section and an upper section, means to retain the sections together and permitting parallel movement of the lower section into overlapping relation, bracing means pivoted at a point spaced from the pane of the door and in the neighborhood of the level of the top of the door and pivoted to the' inner face of the upper section at the center portion thereof, the bracing means being rigid between its pivot points throughout the movement of the upper section, means attached to the front face of each section of the door between the vertical edges thereof and approximately upon the horizontal axis of the center of gravity thereof to operate the door to bring the lower section into overlapping relation with the upper section and raise all sections towards the top of the doorway, a vertical slot in the lower section extending from the upper edge thereof approximately half the height of the section to permit the next aforesaid means attached to the upper section to pass therethrough when the sections are raised, and means to guide the upper end of the side by side sections in a general horizontal direction.

11. A door combination for a door which opens vertically and swings horizontally comprising a sectional door having a lower section and an upper section, means to retain the sections together and permitting movement of the two sections into side by side relation, bracing means pivoted at a point spaced from the plane of the door and in the neighborhood of the level of the top of the door and pivoted to the upper section at the centerportion thereof, the bracing means being rigid between its pivot points throughout the movement of the upper section, means attached to the lower section of the door approximately upon the horizontal axis of the center of gravity and between the vertical edges thereof to operate the door to bring the lower section into side by side relation with the upper section and raise both sections towards the top of the doorway, a vertical slot in one ofthe sections extending approximately half the height of the section to permit the next-aforesaid means to pass therethrough when the sections are swungr horizontally, and cam means to guide the sections in a generally horizontal direction, the cam means being so formed that it retains the point of attachment of the operating means in a verti- 'cal plane as the door moves upwardly.

' 12. A door combination for a vertically opening door comprising a sectional door having at least one lower section and an upper section, means to retain the sections together and permitting parallel movement of the sections into overlapping relation, bracing means pivoted at a point spaced from the plane of the door and in the neighborhood of the level of the top of the door and pivoted to the upper section below thek horizontal axis of the center thereof, the bracing means being rigid between its pivot points throughout the movement of the upper section, means attached to each section of the door approximately upon the horizontal axis of the center of gravity thereof to operate the door to bring the lower sections into overlapping relation with the upper section and raise all sections towards the top of the doorway including differential counterbalancing means, a vertical slot in at least the lower sections extending from the top edge approximately half the height of the section to permit the next aforesaid means to pass therethrough when the sections are raised, and means to guide the upper end of the overlapping sections in a generally horizontal direction.

13. A door combination for a vertically opening door comprising a sectional door having a lower section and an upper section, means to retain the sections together and permitting parallel movement of the lower section into overlapping relation with the upper section, bracing means pivoted at a point spaced from the plane of the door and in the neighborhood of the level of the top of the door and pivoted to the upper section at the center portion thereof, the bracing means being rigid between its pivot points throughout the movement of the upper section,

means attached to each section of the door approximately upon the horizontal axis of the center of gravity thereof to operate the door to bring the lower section into overlapping relation with the upper section and raise both sections towards the top of the doorway including differential counterbalancing means, a vertical slot in the lower section extending from the top edge thereof approximately half the height of the section to permit the next aforesaid means to pass therethrough, and means to guide the upper end of the sections in a generally horizontal direction.

14. A door combination for a vertically opening door comprising a sectional door having a lower section and an upper section, means to retain the sections .together and permitting parallel movement of the lower section into overlapmeans to the upper section when in overlapped relation to operate the door to bring the lower section into overlapping relation with the upper section and Athereafter raise both sections vertically including a differential counterbalancing means, a vertical slot in the lower section extending from. the top edge thereof approximately half the height of the section to permit the next aforesaid means to pass therethrough, and cam means to guide the upper end of the upper section in a generally horizontal direction in-l wardly and thereby carry the lower sections therewith and having a form to maintain the point of attachment of the operating means on the door in a vertical plane as the door moves upwardly and swings toward ahorizontal position under the influence of the bracing means and the cam means.

l5.fAl sectional door in which the sections. are adapted to be moved to side by side relation and swing horizontalhT comprising at least one lower section and an upper section, means t0 retain the` sections together and permitting movement of the lower sections relatively to the upper section into side by side relation, means to swing the door into horizontal position including bracing means intermediate the vertical edges of the door, means to attach door raising and swinging means to the sections of the door at approximately the center thereof and between the vertical edges of the door, and vertical slot means extending approximately half the vertical height of at least one section and in alignment with the attaching means.

16.. A sectional door comprising at least one lower section and an upper section, means to retain the sections together and permitting movement of the lower sections relatively to the upper section into side by side relation, means to swing the door into horizontal position, means to attach operating means to each section of the door at approximately the center thereof and between the vertical edges of the door, and a vertical slot extending approximately half the vertical height of at least one section and in alignment with the attaching means.

17. A sectional door comprising at least, one lower section and an upper section, means to re- Y tain the sections together and permitting paralping relation with the upper section, bracing lel movement of the lower sections relaively to the upper section into overlapping relation, means to attach operating means to the front face of each section of the door at approximate- 1y the horizontal center axis thereof and between the vertical edges of the door, and a vertical slot for each lower section extending from the upper edge thereof approximately half the vertical height of the section and in alignment with the attaching means for the upper section.

18. A sectional door comprising at least one lower section and an upper section; means to retain the sections together and permitting parallel movement of the lower sections relatively to the upper section into overlapping relation including a vertically extending I-beam carried by one section between the vertical edges of the section, and spaced means on either side of the I-beam carried by the other sections; means to attach operating means to the front face of each section of the door at approximately the hori- Zonta-l center axis thereof and between the vertical edges of the door; and the spaced means forming a vertical slot extending from the upper edge of the lower sections approximately half the vertical height of the section and in alignment with the attaching means for the upper section.

19. A sectional door comprising at least one lower section and an upper section, means to retain the sections together and permitting parallel movement of the lower sections relatively to the upper section into overlapping relation including a pair of spaced channels extending vertically of one of the sections and between the Vertical edges thereof, and means carried by the lother section projecting into the slot formed by the spaced channels upon one face of the section; means to attach operating means to the front face of each section of the door at approximately the center thereof and between the vertical edges of the door; and a vertical slot formed by the spaced channels on the other face of the section extending from the upper edge of the lower sections approximately half the vertical height of the section and in alignment with the attaching means for the upper section.

20. A sectional door comprising a lower section and an upper section; means to retain the sections together and permitting parallel movement of the lower section relatively to the upper section in overlapping relation including a vertically extending I-beam carried by the upper section between the vertical edges thereof and projecting beyond the outer face of the section, spaced channels extending vertically of the lower section and forming a slot therebetween upon the inner face thereof to receive the I-beam, and roller means carried by the I-beam and channels; means to attach operating means to the front face of the upper section of the door at approximately the center thereof and between the vertical edges thereof; and means securing the spaced channels together for half the section height to leave a vertical slot extending from the upper edge of the lower section approximately half the vertical height thereof and in alignment with the attaching means for the upper section.

2l. A door combination for a vertically opening door comprising a sectional door having at least one lower section and an upper section;

means to retain the two sections together and' permitting parallel movement of the lower sections into overlapping relation with the upper section; door raising and swinging mechanism including bracing means pivoted at a point spaced from the plane of the door and in the neighborhood of the level of the top of the door and pivoted to the upper section, the bracing means being rigid between its pivot points throughout the movement of the upper section, means attached to the upper section of the door between the vertical edges thereof and within the horizontal center portion of the section to operate the same, means attached to the lower sections to bring the same into overlapping relation with the upper section and raise all sections towards the top of the doorway, and mechanism to guide the upper end of the overlapping sections in a generally horizontal direction; and vertical slot means in at least one of the sections extending from one edge thereof approximately half the height of the section to permit one of the means of the door raising and swinging means to pass therethrough when the sections are brought into overlapping relation.

LESLIE McHARG.