US3722140A

US3722140A - Automatic gate

Info

Publication number: US3722140A
Application number: US00115966A
Authority: US
Inventors: J Newton
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-02-17
Filing date: 1971-02-17
Publication date: 1973-03-27
Anticipated expiration: 1990-03-27

Abstract

An automatic gate characterized by several distinctive features, including: (1) the use of flexibly mounted barrier members forming a collapsible gate that moves downwardly into a recess means to open the gate; and (2) timed hold down means to keep the barrier members lowered for a period of time after a vehicle has moved off an approach ramp that effects the lowering in order to allow passage of long trailers onto the ramp. Also disclosed are specific structures for carrying out the respective embodiments including: (1) the use of a counterweight in the raising means, (2) the use of five or more tubular barrier members for preventing exit of small livestock such as sheep and the like; (3) a cattle guard type approach treadle so that an animal cannot walk on the treadle to open the gate; and (4) an arming lever, and a cam for engaging a free end of the arming lever such that the timer is armed by downward movement of the approach treadle but allowing return of the arming lever and the treadle.

Description

Unite SEQS Pte 1 3,722,30 Newton 27, 1973 AUTOMATIC GATE Primary Examiner-Dennis L. Taylor [76] Inventor: John M. Newton, Rt. 3, Box 207, & Felsma Grapevine, Tex. 76051 I [57] TRACT [22] Filed: Feb. 17, 1971 An automatic gate characterized by several distinctive PP 1151966 features, including: (1) the use of flexibly mounted barrier members forming a collapsible gate that moves 52 us. Cl. ..49/30, 49/132, 49/273 downwardly into a recess means to p t g and 51] Int. Cl. 1.13051 13/04 timed hold down means to p the barrier [58] Field of Search ..49/131, 132, 133, 134,263, bere lowered for a Period of time after a vehicle has 7 49/2 4 2 9 271 3 moved 011 an approach ramp that effects the loweringin order to allow passage of long trailers onto the [56] Referenges Cit d ramp. Also disclosed are specific structures for carrying out the respective embodiments including: (1) the UNITED STATES PATENTS use of a counterweight in the raising means, (2) the, 1,653,716 12 1927 Martin ..49/I31 use of five tubular barrier members f 1 33 312 11 93 Keenan, preventing exit of small livestock such as sheep and 1,988,889 1/1935 Boardman.... the like; (3) a cattle guard type approach treadle so ,8 1 58 at an that an animal cannot walk on the treadle to open the 3,024,549 3/1962 Lubmann gate; and (4) an arming lever, and a cam for engaging 313331331 Z1323 111111111 .2930 X a free end of the mine lever that the time FOREIGN PATENTS OR APPLICATIONS 8/1936 Australia ..49/131 armed by downward movement of the approach treadle but allowing return of the arming lever and the treadle.

17 Claims, 8 Drawing Figures PATENTEUHARZYISB SHEET 10F 4 m RM m m. MM MM m N 1/ B In PATENTEUHARZYIQH 3,722,140

SHEET 2 or 4 PATENTEBmzmn SHEET sUF 4 Ey o6 A TTOR/VEYS AUTOMATIC GATE BACKGROUND OF THE INVENTION 1 Field of the Invention This invention relates to gates such as are employed to block a gap in a fence means at a roadway. More particularly, this invention is related to automatic gates that open automatically to allow passage of vehicles or the like along the roadway and close automatically following passage of the vehicle.

2. Description of the Prior Art The quest for a satisfactory automatic gate is probably almost as old as fences themselves. It is certain that, for many years, men have sought a gate that could be opened and closed by the driver of a vehicle without the necessity of alighting from the vehicle to open the gate. The need for such an automatic gate was especially apparent in foul weather. With the advent of modern vehicles having enclosed cabs to protect the occupants from weather, the quest for automatic gates has intensified. A wide variety of gates have been proposed to enable the operator to actuate the gate from within the vehicle. Many of the power devices of limit the size, or vertical height, of the vehicle whichcould pass through the gates and are subject to unintentional operation by inadvertent lights, aircraft broadcasting on near frequencies, or the like.

Other gates required the vehicle to physically c ontact the gates to force them open, generally damaging both the vehicle and gate a little each time the gate was opened.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevational view of an automatic gate employing one embodiment of this invention and having the barrier members shown in their erected, or closed, position.

FIG. 2 is a cross sectional view of the gate of FIG. 1 taken along the lines II II.

FIG. 3 is a view similar to FIG. 2 showing the barrier members in the collapsed, or open, position.

FIG. 4 is a partial front elevational view, partly in section, of one end of an automatic gate employing another embodiment of this invention.

FIG. 5 is an end view, partly in section, and partly cutaway for clarity, of the embodiment of FIG. 4.

FIG. 6 is a partial perspective view of one end of an automatic gate in accordance with another embodiment of this invention.

FIG. 7 is a partial perspective view of the automatic gate of FIG. 6 being retained in the open position by a timing means.

FIG. 8 is a partial end view, partly in section, illustrating the hold down means of the embodiment of FIG. 6.

DESCRIPTION OF PREFERRED EMBODIMENTS It is an object of this invention to provide an automatic gate that obviates the disadvantages of the prior art structure, yet provide an automatic gate that is inexpensive; that employs simple, long-tested, reliable equipment and is fully automatic; that does not limit the size, or height, of a vehicle that can pass therethrough; and that does not require physical contact between the gate and the vehicle.

It is another object of this invention to provide an automatic gate that accomplishes the foregoing objects and also provides a timed hold down feature to enable a tow vehicle to pass completely over the gate and off the approach treadle means without having the gate assume a closed position in order to allow the approach of an elongated trailer or the like onto the approach treadle means.

These and other objects and features of the present invention will be apparent from the following detailed description taken in conjunction with accompanying drawings.

Referring to FIGS. 1-3, upright support means in the form of upright support members 2 and 4 are positioned on each side of a roadway at respective ends of a fence means 6 so as to block the gap in the fence means at a roadway. As illustrated, each of the support members 2 and 4 comprise a pair of posts that are spaced apart and have means, such as bearing means 8, on their upper ends to rotatably carry an axle, or shaft, 10 joumalled therein. The shaft 10 carries three

pulleys

12, 14 and 16 which are secured to the shaft for rotation concomitantly therewith. The diameter of the first pulley 16 is much greater than the diameter of the

second pulleys

12 and 14 to obtain a speed advantage for reasons which will become clear from the operational discussion hereinafter. Expressed otherwise, a small amount of lineal movement of a flexible member wrapped around the

second pulleys

12 and 14 will produce a much greater lineal movement of a flexible member wrapped around the first pulley 16, since the first pulley 16 turns the same number of revolutions that the small pulleys l2 and 14 turn.

Lateral support braces

18 and 20 project outwardly from each of the support members 2 and 4, respectively, and carry guide pulleys 22. Barrier supporting

cables

24 and 26 each have one

respective end

25 and 27 anchored to the ground adjacent the bases of the support members 2 and 4, and extend over the pulleys 16 and guide pulleys 22 and have their

opposite ends

29 and 31 secured to

respective counterweights

28 and 30. Barrier members 32 are secured to the

cables

24 and 26, as by heat fused balls 33 above and below the respective barrier members. The barrier members should be immobilized against both upward and downward movement with respect to the barrier supporting cable means to keep within an enclosure livestock that have a tendency to lift the barrier members upwardly. For example, hogs have a rooting instinct to try to lift the barrier members with their noses and escape beneath them. Frequently, for larger livestock such as cattle and horses, it will only be imperative to support the barrier members against the force of gravity so only a single ball 33 need be emplaced beneath the barrier members 32. The barrier members 32 extend laterally across the roadway and terminate between and slightly beyond the support members 2 and 4 to prevent passage of livestock or the like through the gate. The end of the fence means 6 is emplaced as close to the gate as desired, commensurate with the dimensions of the livestock that are to be maintained within an enclosure about which the fence means is emplaced.

Approach treadle means, or approach ramps, 34 and 36 are provided on opposite sides of the gate for lowering, or opening, the gate in response to approach of a vehicle, or the like. The approach treadle means 34 and 36 have their outer ends disposed on the surface of the roadway, as by being anchored to the ground by pivots 38 or the like. They have their inner, or free, ends connected to the lower ends of respective

treadle supporting cables

40 and 42. The upper ends of the cables 40 are wound on and secured to pulleys 12, while the upper ends of cables 42 are wound on and secured to pulleys 14.

A shallow recess means 44 is provided for receiving the barrier members 32 when lowered in closely stacked relationship thereinto, as illustrated in FIG. 3. The shallow recess means may be emplaced slightly below the surface of the earth as illustrated, or it may be defined by gate structure; such as a somewhat higher and steeper ramp means 46 emplaced on the surface of the earth; and merely anchored to the earth to prevent lateral displacement by passing vehicles. In either event, the costs are nominal. I

In operation, the gate normally assumes the position shown in FIGS. 1 and 2 with

cables

24 and 26 maintaining the barrier members in a raised, or closed, position to prevent livestock or the like frompassing through the gate and with

cables

40 and 42 supporting thefree ends of the treadle means 34 and 36 in a raised position.

To open the gate, the operator of a vehicle merely drives the vehicle onto the treadle means 34, as shown in FIG. 3. The weight of the vehicle depresses the inner end of the treadle means 34 and acts through cables 40 and pulleys 12 to rotate the shaft and pulleys l4 and 16. Rotation of the pulleys l6 acts to raise the

counterweights

28 and 30 and increase their potential energy; concomitantly allowing the barrier members 32 to fall under the force of gravity to a collapsed position. In the collapsed position, the barrier members 32 are stacked closely adjacent each other in the recess means 44 so they are not damaged by passage of the vehicle thereover. Rotation of the pulleys 14 serves to lower the free end of the treadle means 36 to the depressed position shown in FIG. 3. The operator continues to drive the vehicle over the collapsed barrier means, or members, 32 and treadle means 36 to pass through the gate. As long as the weight of the vehicle is imposed upon either of the treadle means 34 or 36, the barrier means 32 will remain in the collapsed position. As the vehicle moves off of the treadle means 36, however,

counterweights

28 and 30 will fall with the force of gravity, raising the barrier members 32 to close the gate; and will act through

cables

24 and 26 to rotate pulleys l2 and 14. The rotation of

pulleys

12 and 14 acts through

cables

40 and 42 to raise the

treadles

34 and 36. The gate is thus automatically returned to the position of FIGS. 1 and 2.

As indicated hereinbefore, the diameters of the

pulleys

12, 14 and 16 and the dimensions of the

cables

24, 26, 40 and 42 must be chosen so that the barrier members 32 will be allowed to completely collapse into the recess means 44 as the treadle means 34 and 36 travel from the raised position of FIG. 2 to the lowered position of FIG. 3. Moreover, the length of the treadle means 34 and 36 should be sufficient to assure that the vehicle will be clear of the barrier members before the vehicle wheels leave the treadle and the barrier members are allowed to rise.

It will be appreciated that the simple embodiment of FIGS. l-3 affords economical, dependable operation, but has the disadvantage of requiring a length of the treadle means that is adapted to the environment and usage; for example, one length for a suburban home having primarily automobile traffic and a different length for vehicles such as elongated trailer trucks in which the rear wheels of a tow vehicle may depart from the ramps before the wheels of the trailer engage the other approach ramp. Instead of stocking a variety of treadles of different lengths, it is advantageous to employ a timing means that is connected with the lowering means and operable to inhibit operation of the raising means for a predetermined period of time after the gate has been opened. Such an embodiment of this invention employing a timing means is illustrated in FIGS. 4 and 5. Therein, the automatic gate 49 comprises the plurality of barrier members 32 that are flexibly carried with respect to each other for being raised and lowered; raising means 51 connected with the barrier members so as to raise them to form the closed gate when the gate is not being lowered by a lowering means or held open by a timing means; lowering means 53 connected with the barrier members, although by way of the raising means as illustrated, to effect lowering of the barrier members upon the approach of a vehicle or the like; timing means 55; and a shallow recess means 57 disposed intermediate the free ends of the treadle means and having a depth at least equal to the thickness of the approach treadle means for receiving the barrier members when lowered thereinto in closely stacked relationship.

The plurality of barrier members form a collapsible structure as described hereinbefore with respect to FIGS. l3. The barrier members are affixed to the barrier supporting cables 24, as by welding or as described with respect to FIGS. l-3.

In the embodiments of FIGS. 1-3, the raising means comprised a counterweight 28 that was connected via at least one pulley and a lineal means with the barrier members but connected so as to move lineally approximately the same distance as did the top barrier member. In the embodiment of FIGS. 4 and 5, the raising means 51 also comprises a counterweight that is connected with the barrier members by way of at least one pulley and a lineal means. Specifically, the raising means 51 comprises the counterweight 59 that is connected with a small diameter pulley 61 via a lineal member such as cable 62. The small pulley 61 is connected with a large pulley 63 so they rotate concomitantly the same number of revolutions. Both pulleys 61 and 63 are rotatably supported by a shaft 10 journalled in bearing means 8, as described hereinbefore. The large pulley 63 has one end of the barrier supporting cables 24 wrapped around and affixed thereto; so that the barrier members are connected withthe large pulley 63 in the side opposite the connection of the counterweight 59 with the small pulley 61. The barrier members 32 are, consequently, raised and lowered in response to rotation of the large pulley 63 inversely to the lowering and raising of counterweight 59. As can be seen, however, it is unnecessary for the counterweight 59 to travel the same lineal distance as does the top barrier member 32, since the counterweight is connected with a smaller diameter pulley that requires less lineal distance to rotate the same number of revolutions as does the large pulley 63'. Thus, the pulley arrangement effects a speed advantage in movement of the barrier members with respect to the counterweight. Such speed advantage requires, of course, somewhat heavier counterweights than would otherwise be required. The well known principles of elementary physics regarding mechanical and speed advantages and the relationship between the opposing forces are applicable in designing the relative weight of the counterweights and the diameters of the pulleys.

The counterweight S9 is also carried by a lever means 65 that is pivotally mounted at a fulcrum shaft 67 on the upright support member 2. Lever means 65 has a first moment arm 69 extending from the counterweight 59 to the fulcrum shaft 67; and a second moment arm 71 extending from the fulcrum shaft 67 to a connection point, or shaft, 73 for connection with an approach treadle means.

The connection point 73 is connected with a rigid member 75 by way of link 77. As illustrated, a divided approached treadle means is employed in FIGS. 4 and 5. Specifically, an approach treadle 79 that is adapted to receive the wheels on the respective sides of a vehicle is employed instead of having a unitary approach treadle means that spans substantially the entire roadway. The link 77 has a lever extension 81 carrying a cam means, such as pin cam 83, for actuating, or anning, the timing means 55. Specifically, the pin cam 83 moves downwardly as the free end of the treadle 7.9 is moved downwardly by the weight of the vehicle and moves upwardly when the free end of the treadle 79 is moved to its normal raised position. Thus, it can be seen that the lowering means comprises the treadle 79 and the interconnection linkages intermediate the treadle 79 and the lever 65 pivotally carrying the counterweight 59 so as to lift the counterweight 59 directly, rather than by the pulley arrangement of FIGS. 1-3. As can be seen, however, the lowering means is ultimately connected with the barrier members, as by

barrier supporting cables

24 and 26. Consequently, the barrier members 32 are connected with the raising and lowering means so that they move downwardly into the recess means as the counterweight 59 is moved upwardly.

The timing means 55 comprises a hold down means pivotally disposed adjacent at least one of the barrier members for swinging over the barrier member when the barrier members are emplaced in the recess means; retraction means connected with the hold down means for releasing it to allow the barrier members to be raised and effect a closed gate; an inhibit means connected with the retraction means so as to inhibit operation of the retraction means and prevent release of the hold down means for a predetermined period of time after the lowering means is deactivated as by the vehicle or the like rolling therefrom. The retraction means is connected with the lowering means so as to be armed and start a predetermined time interval after the barrier members have been lowered into the recess means. As illustrated, the hold down means comprises a pair of plate means 85 pivotally mounted one at each end of the barrier members 32. The plate means 85 are pivotally mounted ona suitable shaft 87. The shaft 87 is carried by the upright support members 2 and 4. The plate means 85 is suspended from the shaft 87 with its weight eccentric with respect to the shaft 87 so that the plates 85 will swing, under the force of gravity when not otherwise restrained, over the end of the shallow recess means and over the end of the barrier members 32 when emplaced in the recess means. The plate means 85 are connected with the respective retraction means via suitable lineal members 89 so as to pull, or retract, the plate means from over the barrier members after the expiration of a predetermined period of time, and to retain them retracted except when armed or tim- The retraction means illustrated comprises a piston disposed within a cylinder 92 and biased toward its normal position. Specifically, the piston 91 has a piston shaft 93 protruding through one end of the cylinder 92. A spring 95, serving as a biasing means, is disposed about the piston shaft 93 and within the cylinder 92 such that the spring is distorted, as by being compressed, upon lowering of the barrier members 32 and the moving of the piston 91 toward the shaft end of the cylinder 92. Thus, the distorted spring biases the piston toward its normal position. If desired, a compressible fluid chamber 97, shown in dashed lines in FIG. 4, may be employed in conjunction with a compressible fluid on the shaft-spring side of the piston 91. The compressible fluid is compressed to store potential energy and assist the spring in restoring the piston to its normal position. 01' course, the compressible fluid alone may be employed, if desired; although there is a risk that fluid loss would render the retraction means inoperative if the spring 95 is not employed. The piston shaft 93 is connected via a flexible lineal member 99 with a pivotally mounted member 101 that has a notch release means 103. The notch release means 103 is responsively positioned adjacent pin cam 83 sothat as the pin cam 83 moves downwardly inresponse to downward movement of the free end of the approach treadle 79, the pivotally mounted member 81 has its notch release means 103 moved downwardly to pull piston shaft 93 outwardly by way of lineal member 99 over pulley 105. Notch release means 103 has a canted, or angular, approach so that it may be returned to its normal position before the pin cam 83 is returned, yet the pin cam 83 will be guided over the end of the pivotal member 101 and into the notch release means 103 for subsequent arming of the retraction means upon the next approach of a vehicle or the like. The lever extension 81 has sufficient flexibility to allow the pin cam 83 to move over the free end of the member 101 and re-engage the notch release means 103.

The inhibit means comprises fluid 107 in the piston end of the cylinder 92 on the other side of the piston 91 and a flow resistance means 109 that controls the speed the fluid 107 is allowed to flow from the cylinder. If desired, the fluid 107 maybe a liquid flowing from the piston end of the cylinder 92 into a liquid reservoir; or it may be a compressible fluid such as air employing the normal atmosphere as a reservoir. The speed with which the piston 91 is returned to its normal position is controlled by adjustment of the fluid flow resistance means 109, as by turning inwardly on a screw to further obstruct an orifice. If desired, capillaries, or fixed orifices, may be employed instead of an adjustable flow resistance means. Ordinarily, the latter is preferable in order to make the automatic gate more nearly universally acceptable for a variety of vehicles and environments.

As illustrated in FIGS. 4 and 5, a shock absorber 111 is employed to cushion and smooth out operation of the gate, and also minimizing noise. Moreover, as can be seen in FIG. 5, the

respective barrier members

32a and 32b slide along

respective guide members

113 and 115 to facilitate orderly emplacement of the barrier members 32 in the recess means 57. j

The treadle 79 may simply lie along the ground with its end opposite its free end resting on the surface and without any anchoring, or it may be pivotally anchored to the ground. Preferably, where the gate is portable, the treadles are not anchored to the ground, or to the roadway in order to facilitate moving of the automatic gate, as onto oil leases or the like.

In operation, a vehicle; for example, a pick-up truck pulling an elongated livestock trailer; depresses the free end of the treadle 79. The downward movement is transferred via link 77 to raise the counterweight 59 and lower the barrier members 32. As the free end of the treadle 79 moves downwardly, the pin cam means 83 pivots the pivotal member 101, pulling outwardly on the piston shaft 93 and arming the retraction means. After the barrier members 32 have been lowered into the recess means 57, the retraction means will be fully armed and the plate means 85 allowed to swing over and entrap the barrier members 32 in the recess means 57. As the pin cam means 83 reaches the bottom position of the free end of the pivotal member 101, the pin cam 83 rolls free of the notch release means 103 and starts the timing interval. The timing interval, as indicated, is controlled by the adjustment on the fluid flow resistance means 109 opposing the restoring force of the spring 93. In any event, the spring slowly pushes the piston 91 back to its normal position. In the meantime, the vehicle will have rolled off the exit treadle 79 so there will be a period between the rear wheels of the vehicle and the front wheels of the trailer when there is no weight on the treadle 79. But for the timing means, the barrier members would undesirably be raised upwardly, through the downward falling of the counterweight 59, between the tow vehicle and trailer. The plate means 85, however, hold the barrier members 32 trapped in the recess means 57 until the trailer wheels are on the treadles to hold the gate open. Specifically, the spring 93 slowly moves the piston 91 back towards the fluid flow resistance 109, slowly moving the plate means 85 toward the end of the barrier members 32. The time interval adjustment may be anywhere from one to 60 seconds for the timing means. If there is no trailing vehicle, the plate means 85 will be pulled from over the barrier members 32 at the expiration of the terweight 59 will move downwardly, pulling the barrier members-32 upwardly and restoring the free end of the treadle 79 to its upper position. As the pin cam means 83 moves upwardly, it will cam around the guide surface and over the free end of the pivotal member 101 to come to rest in the notch release means 103 so that a subsequent depression of the free end of the treadle means79 will effect arming of the retraction means by pulling downwardly on the free end of the pivotal member 101.

An automatic gate employing another embodiment of the timing means is illustrated in FIGS. 6-8. Referring to FIG. 6, the gate 49 is in the closed position with the barrier members 32 raised. The counterweight 59 is connected with the barrier members 32 similarly as in FIGS. 5 and 6; namely, via cable 62, small diameter pulley 61, large diameter pulley 63, and barrier support cables 24. The pulleys are connected and supported via shaft 10 journalled in bearing means 8. Likewise, the counterweight 59 is also carried by lever means 65 with its long moment arm 69 intermediate the counterweight 59 and the fulcrum shaft 67 and its short moment arm 71 between the fulcrum shaft 67 and the connection point 73. The connection point 73 is connected with the treadle 79 via links 77 and rigid member 75.

In the embodiment of FIG. 6, the hold down means comprises at least one arcuate member that is pivotally mounted adjacent a slot or volume to be occupied by the top barrier member. The arcuate member 1 15 is pivotally mounted with a protruding bottom portion 117 such that as the top barrier member 32, FIG.

8, is moved into its slot in the recess means 57, the arcuate member 115 is pivoted over the top barrier member, as illustrated in dotted lines. A guide member 119 constrains the top barrier members 32 to move downwardly immediately adjacent the arcuate member 115 so as to contact the protruding lower portion 117 and cause the pivotal movement of the arcuate member 115 over the top of the top barrier member 32. The arcuate member 115 is connected via a lineal rod 121 with a lever portion 123. The lever portion 123 is disposed adjacent one end of the barrier members. In the embodiment of FIGS. 6-8, it is only necessary to have the lever portion 123 and its trigger means at one end of the gate. A pivotally mounted trigger means has a notch 127 that is adapted to engage the lever portion when the lever portion 123 is moved into the hold down position, as illustrated in FIG. 7. The trigger means 125 is pivotally carried via shaft 124 on upright support member 2. The trigger means 125 is biased, as by spring 126 to move the free end of the trigger means 125 toward the center of the gate and hold the lever portion 123 in its hold down position when the retraction means 129 is not pulling the trigger means 125 outwardly into the retracted, or normal, position. The lever portion 123 is movable into an unobtrusive position, substantially flat with the ground, as illustrated in FIG. 6, when the gate is raised into the closed position. The retraction means is substantially the same as that described with respect to the embodiment of FIGS. 4 and 5. Specifically, as illustrated, it is a spring-powered, pneumatic cylinder, piston and shaft arrangement having air as the fluid 107 in the piston end of the cylinder and having an adjustable flow resistance means 109.

The retraction means 129 is connected with the trigger means 125 via a flexible lineal member 131 that is taut when the gate is. in the closed position, as illustrated in FIG. 6, but that has slack when the gate is in the open position until the retraction meansnears its normal position. In this way, the trigger means 125 retains the lever portion 123 in the hold down position until just before the retraction means returns to its normal position and, thereafter, releases the lever portion 123 to allow the hold down means 115 to be pivoted into the open position and the barrier members 32 to be returned to the raise position.

The retraction means 129 is connected via flexible lineal member 99 with a pivotally mounted member, or lever, 133 that has a somewhat different form from the pivotally mounted member 101 of FIG. 4. The pivotally mounted member 133' is mounted at the fulcrum shaft 67 carried by the upright support member 2. The flexible member 99 has a turnbuckle 135for adjusting the tension and is disposed over a pulley 137 to facilitate horizontal placement of retraction means 129. In order to effect downward movement of the free end 139 of the pivotally mounted member 133, an eccentrically and pivotally mounted cam. means 141 has a recess means 143 that engages the free end 139 during downward movement of the link 77, concomitantly with the downward movement of the free end of the treadle means 79; and release the free end 139 at its lower position. The cam means 141 is retained at'its lower position, as illustrated in FIG. 7, while the free end 139 of the pivotally mounted lever 133 is slowly returned to its normal position by retraction of the retraction means 129 as air is bled out of the flow resistance means 109, timing out a predetermined time interval. The cam means 141 is mounted eccentrically in order that, as the link 77 is returned to its upper position during the closing of the gate, following the expiration of a predetermined interval and the release of the hold down means 115, the cam means 141 may pivot out of the way of the free end 139 and then pivot back into the normal position as shown in FIG. 6. The pivotal direction in which the lower end of the cam means 141 moves toward the center of the gate, is illustrated by the arrow 145.

In operation, a vehicle has its wheels run onto one or more of the treadles 79, pulling the free end of the treadle 79 downwardly. There is concomitant downward movement of the link 77 and the cam means 141, as well as the connection point 73. Consequently, there is simultaneous upward movement of the counterweight 59, lowering barrier members 32 into the recess means 57; and arming of the retraction means by the downward movement of the free end 139 and inward pulling of the piston shaft 93 of the retraction means 129. The barrier members 32 are positioned in the recess means, as illustrated in dotted lines of FIG. 8 and in FIG. 7. The arcuate members 115 are pivoted into position over the top barrier member to retain the counterweight 59 in its elevated position, as illustrated in FIG. 7. The arcuate member 115 is held in position on top of the top barrier member by lever portion 123 entrapped in the notch 127 of the trigger means 125. The spring (not shown) in the retraction means 129, biases the piston toward its normal position and returns it to its normal position as rapidly as the fluid 107 can be expelled from the flow resistance means 109. The flow resistance means 109 is adjusted, as described hereinbefore, to allow the fluid to flow from the piston end over a predetermined interval of time sufficient to hold the gate in the open position until the wheels of a trailed vehicle can impose a force on the treadle means 79. The following events occur if there is no trailed vehicle. The retraction means 129 is slowed by the inhibit means; such as, the flow resistance means 109; so that a predeterminedtime interval elapses before the spring-powered piston inside the cylinder 129 is returned to its normal position. Immediately prior to returning to its normal position, the flexible lineal member 131 grows taut and pulls the free end of the trigger means 125 outwardly, releasing the lever portion 123. The releasing of the lever portion 123, allows the arcuate members to be pivoted upwardly, allowing the top barrier member 32 to escape. Consequently, the counterweight 59 falls downwardly, raising the gate into the closed position. As used herein, the normal position" is the position when the gate is closed with the barrier members 32 raised. As the connection point 73 is moved upwardly, the pivotal cam means 141 has its free end moved pivotally toward the center of the gate so as to pass around the free end 139 of the lever 133. Thereafter, the cam means 141 falls back into the normal position as illustrated in FIG. 6 such that upon subsequent depression of the free end of the treadle means 79, the free end 139 of the lever 133 will be moved downwardly by the cam means 141 to arm the retraction means 129 again and start another timing interval. I

In the embodiments of FIGS. 4-8, if there is a trailed vehicle, the wheels of the trailed vehicle retain the gate in the closed position until the trailed vehicle clears the exit ramp, or treadle 79.

In the event there is to bev a plurality of trailed vehicles, the timing means will be set for a long time interval; such as, forty to sixty seconds; in order to allow all of the trailed vehicles to clear the treadle means before the gate is released to be raised into its closed position.

As illustrated herein, the raising means comprises a recoil means consisting of a counterweight at each end of the automatic gate such that the potential energy of the counterweight is automatically raised as the barrier members are lowered. It will be appreciated that other recoil means such as a coiled spring or the like, may be employed instead of the counterweight, as long as the potential energy of the recoil means is raised, as the barrier members are lowered, to a value high enough that the barrier members will be automatically raised to effect a closed gate when the barrier members are released.

As illustrated, the barrier members have been shown as discrete members of cylindrical exterior. Preferably, at least five or more barrier members, as illustrated in FIG. 8, are employed with the lower barrier members close enough together to obstruct the exit of smaller animals, when this form is employed. Other forms of barrier members may be employed, if desired. For example, strands of fencing material may comprise the barrier members with suitable interlacing strands providing a closely knit, yet collapsible gate. For example, flexible fencing material such as chainlink fencing or the like may be substituted for or interposed between the barrier members 32 to form a collapsible barrier which will be impervious to small animals such as sheep, goats, swine, dogs, wolves and the like. In such cases, the supporting

cables

24 and 26 may be secured to the top of the barrier members and the bottom of the barrier members may be anchored to the ground. As indicated hereinbefore, the spacing of the fence with respect to the automatic gate will be commensurate with type of animals to be kept in or predators to be kept out.

The

barrier supporting cables

24 and 26 have been illustrated (1) connected only to the top barrier member, and (2) connected with all of the barrier members. This and other equivalent modes of connection may be employed as long as they are connected so as to allow the barrier members to be emplaced closely adjacent each other. The interconnection between the barrier members themselves may be any flexible connection desired that will allow the close emplacement in the collapsed position.

The automatic gate has been illustrated with vertical supporting members. If desired the vertical supporting members may be collapsible also. For example, hydraulically operable concentric sections may be mounted within each other and emplaced to raise and lower the barrier members in response to hydraulic pressure and/or gravity. Ordinarily, such hydraulically operable embodiment is more expensive and is not as nearly universally applicable as the preferred embodiments described and illustrated hereinbefore.

The automatic gate has been illustrated with a shallow trench means defined by shallow recess in the surface of the earth. Preferably, the shallow recess is defined by a means that is an integral part of the gate and that is anchored to the surface of the earth, as by spikes 149, FIG. 7, to prevent lateral displacement as a vehicle rolls onto the treadle means 79. In this way, the gate may be readily lifted onto a vehicle and transported to a new location. Moreover, this embodiment does not require digging of even a shallow trench into the ground and obviates the necessity of having to clean out the shallow trench, or recess'means, dug into the surface of the earth. If desired, the recess means maybe minimal; such as, a space between portions of the treadle means; if the barrier members are not harmed by being run over by the wheels of the vehicle.

The embodiments which have been illustrated hereinbefore employ skeletal treadle means having openings such that they will not be operated by animals; such as, cattle, horses, or hogs. The materials of construction that are ordinarily employed in gates in the outdoors will be employed herein. Ordinarily, the components are formed mostly from metals such as aluminum, iron and steel alloys, or the like. The usual accessories such as cables, bearings, pulleys, and the like may be purchased from hardware stores, since no exotic metallurgical compositions are required.

In suburban areas, the entire operating mechanism may be hidden by beautifying facades such as brick columns emplaced thereabout. In areas where freezing rain or the like is common and in which there is a possibility that the pulleys and other operational parts of the mechanism may become encrusted with ice so as to inhibit ready operation, caps or the like may be emplaced over the pulleys to prevent the freezing of ice thereover.

Thus, it can be seen that the present invention provides an automatic gate having collapsible barrier members, means normally maintaining the barrier members in an erected position and raising and lowering means responsive to the approach of a vehicle or the like for effecting opening and closing of the gate to permit passage of the vehicle, but no passage of livestock thereafter. The automatic gate, in its preferred embodiments, also has a timing means that alleviates problems with the vehicle and a towed vehicle. The invention thereby accomplishes the objects set out hereinbefore, alleviating the objectionable features of the prior art and providing: 1 a gate which does not limit the size of the vehicles which can pass therethrough, since the gate has no top portion extending over the roadway; (2) a gate that is not subject to inadvertent operation because of lights or aircraft broadcasts or the like; (3) a gate that is readily adapted to the predominant type vehicle passing therethrough by providing a timing means to maintain the open position for a predetermined time interval; and (4) a gate that is simple, economical, reliable and requires virtually no maintainence and that may be readily moved to other locations as needed. In fact, the automatic gate of this invention can be installed for less than the cost of a conventional cattle guard.

Although the invention has been described with a certain degree of particularity, it is understood that the present disclosure has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention.

What is claimed is:

1. An automatic gate for blocking a gap in a fence means at a roadway and for automatically opening to allow passage of a vehicle or the like comprising:

a. a plurality of barrier members extending laterally across said roadway, said barrier members being flexibly carried with respect to each other so that said barrier members can be stacked closely adjacent each other when lowered into a recess means;

b. raising means connected with said barrier members so as to raise said barrier members to form said gate; said raising means being self restoring for restoring said gate to its raised position other than when said gate is lowered by a lowering means; said raising means comprising a recoil means that includes a counterweight of sufficient weight to be pulled downwardly by gravity to pull said barrier members upwardly to close said gate; said counterweight being connected with said barrier members via a first pulley so as to move substantially the same distance as the top barrier member;

. lowering means connected ultimately with said barrier members so as to impose a force to effect lowering of said barrier members upon the approach of said vehicle or the like; said lowering means comprising an approach treadle means that is pivotally disposed in the approach to said gate and has its free end connected with a second pulley that is smaller than said first pulley and that is connected with said first pulley such that said first pulley rotates the same number of revolutions that said second pulley is rotated; whereby when said approach treadle is moved downwardly by the weight of said vehicle or the like, said gate is opened by lowering said barrier members and said counterweight is raised; and said gate is closed by raising said barrier members through the downward movement of said counterweight after said vehicle has passed off said approach treadle means; and

. recess means for receiving said barrier members when lowered thereinto in closely stacked relationship.

2. An automatic gate for blocking a gap in a fence means at a roadway and for automatically opening to allow passage of a vehicle or the like comprising:

b. raising means connected with said barrier members so as to raise said barrier members to form said gate; said raising means being self restoring for restoring said gate to its raised position other than when said gate is lowered by a lowering means; said raising means comprising. a recoil means in the form of a counterweight having sufficient weight to be pulled downwardly by gravity to pull said barrier members upwardly to close said gate; said barrier members being connected with one side of a first pulley and said counterweight being connected with the opposite side of'a second pulley that is smaller than said first pulley and that is connected with said first pulley such that said first pulley rotates the same number of revolutions that said second pulley is rotated and such that when said counterweight is moved a first distance in a first direction, said barrier members are moved a greater distance in the opposite direction;

. lowering means connected ultimately with said barrier members so as to impose a forceto effect lowering of said barrier members upon the approach of said vehicle or the like; said lowering means comprising an approach treadle means that is pivotally disposed in the approach to said gate and linkage means connecting said counterweight with the free end of said approach treadle means such that said counterweight is raised as the free end of said approach treadle means is depressed; and

recess means for receiving said barrier members when lowered thereinto in closely stacked relationship.

3. The automatic gate of. claim 2 wherein said counterweight is carried by a pivotally mounted lever means that is also connected with said approach treadle means and has a first moment arm between a fulcrum shaft means and said counterweight and a second moment arm between said fulcrum shaft means and the point of connection of said treadle means.

4. The automatic gate of claim 3 wherein said first moment arm is longer than said second moment arm to obtain a speed advantage whereby said counterweight is moved a greater distance than is said free end of said approach treadle means and in the opposite direction.

5. The automatic gate of claim 3 wherein said plurality of barrier members comprise at least five longitudinal members.

6. The automatic gate of claim 5 wherein the top longitudinal member is a rigid longitudinal member that has sufficient strength to bear the weight of the remaining barrier members and is connected therewith by a flexible lineal member; and is connected ultimately with said raising means and said lowering means.

7. An automatic gate for blocking a gap in a fence means at a roadway and for automatically opening to allow passage of a vehicle or the like, comprising:

a. a plurality of barrier members extending laterally across said roadway, said barrier members being flexibly carrier with respect to each other so that said barrier members can be stacked closely adjacent to each other when lowered into a recess means;

b. raising means connected with said barrier members so as to raise said barrier members to form said gate; said raising means being self restoring for restoring said gate to its raised position other than when said gate is lowered by a lowering means or held down by a timing means; lowering means connected ultimately with said barrier members so as to impose a force to effect lowering of said barrier members upon the approach of said vehicle or the like; timing means connected with said lowering means and operable to inhibit'operation of said raising means for a predetermined period of time after said gate has been opened by lowering said barrier members into a recess means; said timing means comprising:

i. hold down means pivotally disposed adjacent at least one of said barrier members for swinging over said barrier member when said barrier member is emplaced in said recess means;

ii. retraction means connected with said hold down means for releasing it to allow said barrier members to be raised and effect a closed gate; said retraction means being connected with said lowering means so as to be armed and start a predetermined time interval after said barrier members have been lowered into said recess means; and

iii. inhibit means connected with said retraction means so as to inhibit operation of said retraction means and prevent release of said hold down means for a predetermined period of time after said lowering means is deactivated by said vehicle or the like rolling therefrom; and

8. The automatic gate of claim 7 wherein said hold down means comprises a pair of plate means pivotally mounted one at each end of said barrier members for swinging over each end of said barrier members emplaced in said recess means; and wherein said retraction means is connected with said plate means for pulling said plate means from over each end of said barrier members; wherein said retraction means is connected with said lowering means so as to allow said plate means to be positioned over said ends of said barrier members after said barrier members have been lowered into said recess means; and wherein said inhibit means prevents retraction of said plate means for a predetermined period of time.

9. The automatic gate of claim 8 wherein said retraction means comprises a spring powered piston disposed within a cylinder with said spring on one side of said piston, and a piston shaft extends from said piston exteriorly of said cylinder for connection with said plate means and ultimately with said lowering means; said spring being distorted upon lowering of said barrier members so as to bias said piston toward its normal position; and wherein said inhibit means comprises fluid in said cylinder on the other side of said piston and a fluid flow resistance controlling the speed said fluid is allowed to flow from said cylinder.

10. The automatic gate of claim 9 wherein said lowering means includes an approach treadle means that is moved downwardly in response to weight of said vehicle or the like; a compressible fluid is contained in said cylinder with said spring and a compressible fluid chamber is also connected via a conduit and an adjustable valve means with the end of said cylinder containing said spring and said compressible fluid so that said compressible fluid is flowed into said compressible fluid chamber at super atmospheric pressure to store energy to help said spring restore said piston to its normal position.

11. The automatic gate of claim 10 wherein said piston shaft is also connected with a pivotally mounted member that has a notch release means that is responsively positioned adjacent a cam means that moves responsive to movement of said lowering means, said cam means moving in a first direction in response to downward movement of said approach treadle means and in a second direction in response to upward movement of said approach treadle means, said pivotally mounted member being movable so as to emplace said plate means over said barrier members in said notch release means in response to movement of said cam means in said first direction and disengagement of said cam means; and returning to its normal position after expiration of said predetermined interval of time; said cam means being semi-flexibly mounted so as to slide over the free end of said pivotally mounted member to return to its normal position engaging said notch release means after said pivotally mounted member has returned to its normal position.

12. The automatic gate of claim 7 wherein said hold down means comprises at least one arcuate member that is pivotally mounted adjacent a slot portion of said recess means that is to be occupied by the top barrier member in the open position and is pivotally mounted with a protruding bottom portion such that as said top barrier member is moved into said recess means, said arcuate member is pivoted over said top barrier member; said arcuate member being connected via a lineal rod with a lever portion, said lever portion being disposed adjacent one end of said barrier members; a pivotally mounted and biased trigger means that is adapted to engage said lever portion when said lever portion is moved into said hold down position; said lever portion being moved into an unobtrusive position when said gate is raised into the closed position; and wherein said retraction means is connected with said trigger means for disengaging said trigger means from said lever portion upon the expiration of said predetermined time interval.

13. The automatic gate of claim 25 wherein said lowering means comprise a treadle means, a rigid member connected with said treadle means, a link means connected with said rigid member and ultimately connected with said raising means, wherein said link means is connected with an eccentric, pivotally mounted cam means having a recess means for engaging a free end of a pivotally mounted lever; wherein said pivotally mounted lever is connected with a support means via a fulcrum shaft and is connected at its end opposite its free end by a flexible lineal member with a retraction means so as to arm said retraction means when the free end of said pivotal lever is moved downwardly by said pivotally mounted eccentric cam means on said link means; said eccentric, pivotally mounted cam means being mounted so that its free end pivots inwardly and around the free end of said pivotally mounted lever means for returning to its normal position after said lever means has returned to its normal position to emplace said cam means in its normal position operable to move the free end of said pivotally mounted lever means downwardly in response to downward movement of the lowering means.

14. An automatic gate for blocking a gap in a fence means at a roadway and for automatically opening to allow passage of a vehicle or the like, comprising:

a. upright support means disposed on each side of said roadway; a plurality of barrier members extending laterally across said roadway and having their ends disposed adjacent said upright support means, said barrier members being joined together vertically by flexible lineal members so that said barrier members can be lowered into a recess means;

0. raising means connected with said barrier members so as to raise said barrier members to form said gate; said raising means comprising a source of potential energy sufficient to be self restoring so as to restore said gate to its raised position other than when said gate is lowered by a lowering means or retained in its lowered position by a timing means;

d. lowering means connected with said barrier members via said raising means and operable to effect lowering of said barrier members by increasing the potential energy of said raising means; said lowering means including a pivotal approach treadle means that has its free end movable downwardly in response to weight of said vehicle or the like thereon, said lowering means also having a link means carrying a cam means that moves upwardly and downwardly concomitantly with the free end of said approach treadle means;

e. timing means connected with said lowering means and operable to inhibit operation of said raising means for a predetermined period of time after said gate has been opened by lowering said barrier members into a recess means and after said vehicle or the like rolls from on said approach treadle means; said timing means including:

i. hold down means pivotally disposed adjacent at least one of said barrier members for swinging over said barrier member when said barrier member is emplaced in a recess means;

ii. retraction means connected with said hold down means for releasing it to allow said barrier members to be raised into a normal position; said retraction means being connected with a pivotally mounted member that is responsively positioned adjacent said cam means for arming said retraction'means in response to downward movement of said cam means; said pivotally mounted member effecting arming of said retraction means by increasing the potential energy therein in response to downward movement of said cam means; said cam means being flexibly mounted so as to allow upward movement of the free end of said pivotally mounted member and subsequent movement of said cam means to its normal position over said free end of said pivotally mounted member; and

iii. inhibit means connected with said retraction means so as to inhibit operation of said retraction means and prevent release of said hold down means for a predetermined time interval after said lowering means is deactivated by said vehicle or the like rolling therefrom; and

f. recess means for receiving said barrier members when lowered thereinto in closely stacked relationship.

15. The automatic gate of claim 14 wherein said retraction means comprises a piston and piston shaft disposed, respectively, within and partially within a cylinder with a bias means on one side of said piston; and said inhibit means comprises a fluid on the other side of said piston and a fluid flow resistance that is adjustable for adjustment of the predetermined time interval.

16. The automatic gate of claim 14 wherein said raising means comprises a weight that is mounted on a lever that is pivotally carried by said upright support means at a first fulcrum point, said weight also being connected with a second pulley that is drivingly connected with a first pulley that is larger in diameter than said second pulley for effecting a speed advantage such that at least a top barrier member which is connected with said first pulley is lowered more rapidly than said counterweight is raised; said lever arms having a first moment arm from said weight to said fulcrum point that is greater than a second moment arm from said fulcrum point to a point of connection with said approach treadle means so as to effect a speed advantage in raising said counterweight when the free end of said approach treadle means is depressed downwardly.

17. The automatic gate of claim 16 wherein said pivotally mounted lever carrying said counterweight is also connected with said upright support means via a shock absorber means to effect smooth transition from a position of low potential energy to a position of higher potential energy and vice versa.

Claims

1. An automatic gate for blocking a gap in a fence means at a roadway and for automatically opening to allow passage of a vehicle or the like comprising: a. a plurality of barrier members extending laterally across said roadway, said barrier members being flexibly carried with respect to each other so that said barrier members can be stacked closely adjacent each other when lowered into a recess means; b. raising means connected with said barrier members so as to raise said barrier members to form said gate; said raising means being self restoring for restoring said gate to its raised position other than when said gate is lowered by a lowering means; said raising means comprising a recoil means that includes a counterweight of sufficient weight to be pulled downwardly by gravity to pull said barrier members upwardly to close said gate; said counterweight being connected with said barrier members via a first pulley so as to move substantially the same distance as the top barrier member; c. lowering means connected ultimately with said barrier members so as to impose a force to effect lowering of said barrier members upon the approach of said vehicle or the like; said lowering means comprising an approach treadle means that is pivotally disposed in the approach to said gate and has its free end connected with a second pulley that is smaller than said first pulley and that is connected with said first pulley such that said first pulley rotates the same number of revolutions that said second pulley is rotated; whereby when said approach treadle is moved downwardly by the weight of said vehicle or the like, said gate is opened by lowering said barrier members and said counterweight is raised; and said gate is closed by raising said barrier members through the downward movement of said counterweight after said vehicle has passed off said approach treadle means; and d. recess means for receiving said barrier members when lowered thereinto in closely stacked relationship.

2. An automatic gate for blocking a gap in a fence means at a roadway and for automatically opening to allow passage of a vehicle or the like comprising: a. a plurality of barrier members extending laterally across said roadway, said barrier members being flexibly carried with respect to each other so that said barrier members can be stacked closely adjacent each other when lowered into a recess means; b. raising means connected with said barrier members so as to raise said barrier members to form said gate; said raising means being self restoring for restoring said gate to its raised position other than when said gate is lowered by a lowering means; said raising means comprising a recoil means in the form of a counterweight having sufficient weight to be pulled downwardly by gravity to pull said barrier members upwardly to close said gate; said barrier members being connected with one side of a first pulley and said counterweight being connected with the opposite side of a second pulley that is smaller than said first pulley and that is connected with said first pulley such that said first pulley rotates the same number of revolutions that said second pulley is rotated and such that when said counterweight is moved a first distance in a first direction, said barrier members are moved a greater distance in the opposite direction; c. lowering means connected ultimately with said barrier members so as to impose a force to effect lowering of said barrier members upon the approach of said vehicle or the like; said lowering means comprising an approach treadle means that is pivotally disposed in the approach to said gate and linkage means connecting said counterweight with the free end of said approach treadle means sUch that said counterweight is raised as the free end of said approach treadle means is depressed; and d. recess means for receiving said barrier members when lowered thereinto in closely stacked relationship.

3. The automatic gate of claim 2 wherein said counterweight is carried by a pivotally mounted lever means that is also connected with said approach treadle means and has a first moment arm between a fulcrum shaft means and said counterweight and a second moment arm between said fulcrum shaft means and the point of connection of said treadle means.

7. An automatic gate for blocking a gap in a fence means at a roadway and for automatically opening to allow passage of a vehicle or the like, comprising: a. a plurality of barrier members extending laterally across said roadway, said barrier members being flexibly carrier with respect to each other so that said barrier members can be stacked closely adjacent to each other when lowered into a recess means; b. raising means connected with said barrier members so as to raise said barrier members to form said gate; said raising means being self restoring for restoring said gate to its raised position other than when said gate is lowered by a lowering means or held down by a timing means; c. lowering means connected ultimately with said barrier members so as to impose a force to effect lowering of said barrier members upon the approach of said vehicle or the like; d. timing means connected with said lowering means and operable to inhibit operation of said raising means for a predetermined period of time after said gate has been opened by lowering said barrier members into a recess means; said timing means comprising: i. hold down means pivotally disposed adjacent at least one of said barrier members for swinging over said barrier member when said barrier member is emplaced in said recess means; ii. retraction means connected with said hold down means for releasing it to allow said barrier members to be raised and effect a closed gate; said retraction means being connected with said lowering means so as to be armed and start a predetermined time interval after said barrier members have been lowered into said recess means; and iii. inhibit means connected with said retraction means so as to inhibit operation of said retraction means and prevent release of said hold down means for a predetermined period of time after said lowering means is deactivated by said vehicle or the like rolling therefrom; and e. recess means for receiving said barrier members when lowered thereinto in closely stacked relationship.

14. An automatic gate for blocking a gap in a fence means at a roadway and for automatically opening to allow passage of a vehicle or the like, comprising: a. upright support means disposed on each side of said roadway; b. a plurality of barrier members extending laterally across said roadway and having their ends disposed adjacent said upright support means, said barrier members being joined together vertically by flexible lineal members so that said barrier members can be lowered into a recess means; c. raising means connected with said barrier members so as to raise said barrier members to form said gate; said raising means comprising a source of potential energy sufficient to be self restoring so as to restore said gate to its raised position other than when said gate is lowered by a lowering means or retained in its lowered position by a timing means; d. lowering means connected with said barrier members via said raising means and operable to effect lowering of said barrier members by increasing the potential energy of said raising means; said lowering means including a pivotal approach treadle means that has its free end movable downwardly in response to weight of said vehicle or the like thereon, said lowering means also having a link means carrying a cam means that moves upwardly and downwardly concomitantly with the free end of said approach treadle means; e. timing means connected with said lowering means and operable to inhibit operation of said raising means for a predetermined period of time after said gate has been opened by lowering said barrier members into a recess means and after said vehicle or the like rolls from on said approach treadle means; said timing means including: i. hold down means pivotally disposed adjacent at least one of said barrier members for swinging over said barrier member when said barrier member is emplaced in a recess means; ii. retraction means connected with said hold down means for releasing it to allow said barrier members to be raised into a normal position; said retraction means being connected with a pivotally mounted member that is responsively positioned adjacent said cam means for arming said retraction means in response to downward movement of said cam means; said pivotally mounted member effecting arming of said retraction means by increasing the potential energy therein in response to downward movement of said cam means; said cam means being flexibly mounted so as to allow upward movement of the free end of said pivotally mounted member and subsequent movement of said cam means to its normal position over said free end of said pivotally mounted member; and iii. inhibit means connected with said retraction means so as to inhibit operation of said retraction means and prevent release of said hold down means for a predetermined time interval after said lowering means is deactivated by said vehicle or the like rolling therefrom; and f. recess means for receiving said barrier members when lowered thereinto in closely stacked relationship.