US3003167A

US3003167A - Bridging structures

Info

Publication number: US3003167A
Application number: US770787A
Authority: US
Inventors: Marion F Smith
Original assignee: DODGE STEEL Co
Current assignee: DODGE STEEL Co
Priority date: 1958-10-30
Filing date: 1958-10-30
Publication date: 1961-10-10
Anticipated expiration: 1978-10-10

Description

Oct. 10, 1961 M. F. SMITH 3,003,167

BRIDGING STRUCTURES Filed Oct. 50, 1958 3 Sheets-Sheet l INVENTOR.

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Oct. 10, 1961 M. F. SMITH BRIDGING STRUCTURES Filed oct. so; 195e 3 Sheets-Sheet 2 INVENTO?. Mr/3121751771177, BY

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Oct. 10, 1961 M. F. sMlTH 3,003,167

BRIDGING STRUCTURES Filed Oct. 50, 1958 3 Sheets-Sheet 3 life /Ijgc JBZ 13a A BWM/y @auf A TTORNE YS.

3,003,167 BRIDGING STRUCTURES Marion F. Smith, Philadelphia, Pa., assignor to Dodge Steel Company, Philadelphia, Pa., a corporation of Pennsylvania Filed Oct. 30, 1958, Ser. No. 770,787 4 Claims. (Cl. 14-71) This invention relates to bridging structures. More particularly, it is concerned with bridging structures of a kind in which a spanning element permanently connected to a platform is movable from a normally retracted position on the platform to span an interval between said platform and another platform either of a mobile or stationary type.

The chief aim of my invention is to provide a simple and inexpensive bridging structure of the kind referred to, wherein the spanning element is easily and quickly extended from its normal retracted position on the one platform into bridging relation with the other platform, and simultaneously upwardly tilted and nally lowered to bridging position.

In connection with a bridging structure having the above mentioned attributes, it is a further aim of my invention to provide simple stop and locking means by which the spanning element is securable against accidental displacement in either its normally retracted position, or in its extended position bridging the interval between the two platforms.

As will be readily evident from subsequent disclosure hereinafter, the bridging structure of my invention is adaptable for' use in bridging the clearance interval between the platforms of two coupled flat top railway cars, between the deck of a boat or ship and a pier or dock, or between the floor of a delivery truck and a loading or unloading platform.

Other objects and attendant advantages will appear from the following detailed description wherein:

FIG. 1 is a fragmentary view in top plan showing two platforms of which the confronting ends are spaced by an interval, and a spanning element conveniently embodying my invention as associated with one of the platforms and shown in its normal `retracted condition.

FIG. 2 is a View similar to FIG. 1 showing the structure extended to span the interval between the two platforms.

FIG. 3 is a fragmentary view in elevation looking as indicated by the angled arrows III-III in FIG. 2.

FIG. 4 is a fragmentary view in cross section drawn to a larger scale and taken as indicated by the angled arrows IV-IV in FIGS. 2 and 3.

FIG. 5 is a fragmentary view in elevation of the right end portion of FIG. 3 drawn to a larger scale.

FIG. 6 is a detail view in elevation on `a larger scale looking as indicated by the angled arrows VI-VI in FIG. 2.

FIGS. 7-11 are diagrammatic views showing successive positions of a cam member included in the bridging structure.

With more specific reference iirst to FIGS. 1-4 of these illustrations, the numerals 1 and 2 respectively designate two platforms of vwhich the contiguous ends are spaced by an interval 3. As exemplified in FIGS. 3 and 4 the platform 1 is shown as having a foundation frame 4 which may be of structural steel.

' The bridging structure with which the present invention is more especially concerned comprises a spanning element 5. As shown, this spanning element 5 is a rectangular oblong in configuration and has a top surface 6 of stout plate metal which is upwardly arched in the direction of its length and to which are welded at the bot- States Patent rice tom and adjacent its

longer side edges

6a and 6b, invert T

section reinforcing bars

7 and 8. Also welded to the bottom of the element 5 along its longitudinal center is an invert T section reinforcing bar 9. Similarly integrated with the plate 6 at the bottom are two laterallyspaced transverse angle section reinforcing bars 1t) and 11 and a curved cam bar 12 fashioned from invert T section material, the transverse bar 11B extending between and being integrated with the

longitudinal bars

7 and 8. The transverse reinforcing bar 11 extends between and is integrated 'with the longitudinal and center bars 9 and 8, and the cam bar `12 is arranged beneath and welded to the bottom of said plate 6 across one corner thereof. The upright lianges of the

bars

7, 8 and 9, and the cam bar 12 have their top edges curved, as best seen in FIGS. 3 and 7-11, to archedly support the top plate 6 of the span ning element 5. At the rear corner occupied by the cam bar 12, the element 5 has a horizontal axis pin 15 which passes through a bracket 15a and through the head 16 at the top of a pendent vertical axis swivel bolt 17 rotatively engaged in a bearing 18 tixedly set into the metallic underframe 4 of the platform 1 as shown in FIG. 4, the cam bar being curved on an arc struck from the axis of said bolt. Pin 20a passes through bracket 20h and supports roller 2t) at the immediately adjacent corner of the element 5. As a consequence of this construction, it will be seen that the element 5 can be swung outwardly about the vertical axis swivel bolt 17 from a retracted position on the platform 1 to the bridging position of FIG. 2 and will be at the same time tilted by movement upwardlyr about the

horizontal pivots

15 and 20a so that its swinging end will clear the top of platform 2 until the element 5 is fully moved to bridging position. Somewhat inwardly of the longitudinal reinforcing bar S the element 5 is provided at the bottom at the corner, in the direction of the edge 6C remote from the corner occupied by the swivel bolt 17, with a roller 20 which is adapted to travel over a curved metallic track 21 set into the top of platform 1 in concentric relation to the axis of said bolt 17. Normally, the element 5 is positioned as shown in FIG. 1 crosswise of the platform 1 and wholly within the end portion of the latter with the edge 6c engaged, at the corner at a point adjacent the edge 6b, with a stop lug 22 upstanding from the platform. A similar lug 23 is provided on the platform 1 for engagement by the edge 6a to serve as a stop for limiting the outward swing of element 5 as shown in FIG. 2.

Welded to the end of the underframing 4 of the platform 1 is a socket 25 for reception of a removable locking pin 25 (FIGS. l, 2 'and 6) which, in cooperation with the side edge 6a, serves as `a locking means to prevent displacement of the element 5 when it is in the retracted position of FIG. r1, and also in cooperation with the side edge 6b when it is in extended position as in FIG. 2. To insure lagainst loss of the pin 26, it is attached, by a flexible element in 'the form of a chain 27, to the underframing 4 of the platform 1 at 28. Also, Ialiixed to the front end of the underframing 4 of the platform 1 is a bracket 30 for a roher 31 over which the arcuate cam bar 12` is adapted to ride when the element 5 is being moved.

By reference to FIGS. 7-11 it will be noted that the `bottom surface at Ithe leading end of the arcuate cam bar 12 is inclined downwardly and outwardly from one end at Ia slight angle to the horizontal as at 12a to meet with a straight horizontal mid-portion 12b, and that outwardly ybeyond said straight mid-portion 412b said edge is sloped upwardly at a somewhat sharper angle as at 12C to a depressed portion 12d, and thereafter slopes downwardly land outwardly at 4a gentler angle to the horizontal as at 12e to the opposite or outer end of said cam bar.

Operation In preparation for moving the spanning element from the normally retracted idle position of FIG. 1 to the bridging position of FIG. 2, the locking pin 26 is first withdrawn from its socket 25. With the element 5 now free, it is swung outwardly about the swivel bolt 17 as ian axis, and `as the bottom edge portion 12a of cam bar 12 rides the roller 31, the spanning element 5 is gradually lifted and by the `time the bottom edge portion 12b of said cam bar reaches `said roller, the leading outer corner portion of element 5 is raised to a level clear of the top of the platform 2 when element 5' reaches the position indicated in broken lines yat A in FIG. 1. As the bottom edge portion 12b of cam bar 12 later overtravelsl the roller 31, the leading corner of the element 5 is held at the aforesaid level until it reaches the position indicated in broken lines lat B in FiG. l with said corner overhanging the platform 2. Then as the element 5 is further swung and the slope 12e of the cam bar 12 rides the roller 31 as in FIG. 10, the element 5 is 'lowered rather rapidly and the edge portion 6a is let down into sliding engagement with the top of the platform 2. In its further movement, the element 5 is finally arrested in bridging position by engagement of its side edge 6a with the stop lug 23 on the platform 1 with the notch 12d between the sloping edge portions 12C and 12e of the cam bar registered with but free of contact with the said roller as in FIG. 11. In order to permit the `swinging end portion of the element 5 to rest firmly upon the platform 2 `and relieve roller 20 of any load responsibility when in bridging position, an opening 35 (FIGS. 2 and 4) has been provided in the top of the platform 1 into which the roller 20 can recede. With the element 5 now fully moved to bridging position, the bolt 25 is replaced in its socket 26 to lock the element against displacement. ln the return swing of the element 5 it is tilted upwardly about the horizontal pivot axis as the edge portion 12C of the cam bar 12 overrides the roller 31 and is so held for a time with the end edge 6d of said element 5 clear of the top of the platform 2. As the return swing of the element 5 continues, said element is gradually let down as the edge portion 12a of the cam bar 12 overrides the roller 31 incident to which the roller 20 is lbrought into engagement with the track plate 21. After the spamiing element S has been swung to fully retracted position with the edge 6c thereof stopped by the lug 22 on the platform 1 `as in FIG. l, the pin 26 is re-inserted into the socket to `lock said element in place. To facilitate the above described manipulation of element 5 it is provided at the corner regions of its swinging end portion with apertures 36 into which a hook at the end of a pull `rod can be selectively engaged. Due to the provisions made for upwardly tilting the element 5 as the outward swing is initiated, my improved bridging `structure will adapt itself for use with platforms 2 which may differ in level from that of the platform 1, as will be 'evident from the broken line showings in FIG. 3.

While in accordance with the provisions of the statutes, I have illustrated land described the best form of embodiment of my invention now known to -me it will be apparent to those skilled in the art that changes may be made in the form of the apparatus described without departing from the spirit and scope of the invention, as set forth in the appended claims, and ythat in some cases certain vfeatures of my invention may be used to advantage without a corresponding use of vother features.

Having thus described my invention, yI claim:

1. A bridging structure spanning an interval between the confronting ends of two platforms, said structure comprising a substantially flat polygonal spanning element 4 adapted to normally rest in retracted position upon one of the platforms; a swivel bolt pendently connected at its upper end by a horizontal pivot pin to the underside of the spanning element at one rear corner thereof; a vertical axis socket bearing for said bolt secured to said one platform; means for restraining the swivel bolt against axial movement in the socket bearing; a cam bar afiixed to the under face of the spanning element and curved on an arc centered in the axis of the swivel bolt, said cam bar having along the bottom thereof, -a cam surface portion sloped downwardly and outwardly from the leading end of the bar and meeting with the horizont-a1 intermediate poition, a portion sloping upwardly and outwardly from the horizontal portion to a depressed portion, and a downwardly and `outwardly sloping portion beyond said depressed portion; and a roller for cooperation with the cam bar journaled in a bracket secured to the outer edge of said one platform at a distance substantially equal to the radius of said cam bar whereby, as the spanning element is swung outward from normally retracted position crosswise `of said one platform about the swivel bolt and the upwardly inclined portion of the same surface of the track overrides said roller, the spanning element is first tilted upward slightly about the horizontal pin aforesaid to bring its distal end above the level of the other platform and then so held for a time as the intermediate level portion of the cam bar overrides said roller; and whereby upon approach of said element to bridging position, it is gradually let down until its distal end finally bears upon said other platform as the depressed portion of the cam bar overrides said roller, and vice versa.

2. A bridging structure characterized as in claim 1, further including a roller supported from the underside of the spanning element at the other rear corner thereof; and an arcuate track for said roller, said track being curved on `an arc having its center in said swivel bolt and being secured upon the top Of said one platform.

3. A bridging structure characterized as in claim 1, further including a pair of stop abutments secured at spaced intervals upon said one platform, one abutment for limiting the outward swing of the spanning element and the other `abutment for limiting the inward or return swing of the spanning element.

4. A `bridging structure characterized as in claim l, further including a vertical axis socket member affixed to the outer edge of said one platform iat a distance from the axis of the swivel bolt equal to the width of the spanning element, and 'a retractable stop pin engageable into said socket member for locking the spanning element against accidental displacement either in normal retracted position on the said one platform, or in bridging position.

References Cited in the tile of this patent UNITED STATES PATENTS 33,606 Selser Oct. 29, 1861 214,530 Snyder Apr. 22, 1879 602,460 Mason Apr. 19, 1898 2,188,554 Marianne Jan. 30, 1940 2,329,855 Ryder Sept.'21, 1943 2,372,574 Haynes Mar. 27, 1945 2,602,944 Richardson July 15, 1952 2,617,131 Harris Nov. 11, 1952 2,641,785 Pitts et al June 16, 1953 2,817,102 Harris Dec. 24, 1957 FOREIGN PATENTS 14,158 Sweden July 9, 1901