US20040164288A1

US20040164288A1 - Material handling gate system

Info

Publication number: US20040164288A1
Application number: US10/374,010
Authority: US
Inventors: Michael Williamson
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-02-25
Filing date: 2003-02-25
Publication date: 2004-08-26

Abstract

A barrier system for use with a material storage area comprises a pair of gates having a first closed position spanning a zone of access to the material storage area and a second open position displaced from the zone of access to the material storage area. A fluid, e.g., air or liquid, control system includes a sensor which activates the control system for movement of the gates between the gate positions, the sensor being activated or deactivated by sensing the presence of a material handling device, e.g., a forklift, approaching or withdrawing from the zone of access. The system is particularly useful for placement on mezzanine levels such that the gates at their closed position precludes workers on the mezzanine from accidentally stepping off the mezzanine while allowing for selectable access to the material storage area by material handlers on the ground floor therebelow. The system is adaptable for manual operation.

Description

BACKGROUND OF THE INVENTION

This invention is directed to a material handling gate system and, more particularly, to a gate system responsive to the approach of a material handler so as to provide a safe zone of access of a material storage area.

The attention to worker safety in material handling environments is a burgeoning one. In warehouses, ground floor and mezzanine storage levels may be utilized so as to increase the space for storage. The materials are normally stored on a pallet which allows for the materials to be handled by a forklift or the like.

Thus, a mezzanine storage area must present an unrestricted zone of access to the material handler therebelow. In turn, this free access presents a safety hazard to workers on the mezzanine level as the possibility arises that workers may misstep and fall from the mezzanine. Accordingly, it is desirable to provide a safety barrier along the mezzanine level without restricting forklift access to the materials stored on the mezzanine.

In response thereto I have invented a gate system which regulates access to a material storage area. At least one gate is positioned along a zone of access fronting the material storage area so as to present a barrier therealong. The closed barrier not only precludes access but also precludes a worker from stepping off the mezzanine. Upon a material handler, e.g., a forklift, approaching the zone of access an ultrasonic sensor recognizing the presence of the forklift mast activates an electro-pneumatic control system which pivots the barrier from the closed position to an open position displaced from the zone of access. This open position allows forklift access to place or retrieve pallets in the storage area. Upon forklift withdrawal the sensor, recognizing the absence of the forklift, de-energizes the electro-pneumatic control system pressure so as to allow the gate to return to its closed position. My preferred system preferably employs a pair of gates spanning each zone of access; however, a single gate may be used to span a zone of access when the zone span is shorter than usual. Although an air fluid/pneumatic control system has been disclosed, a liquid fluid/hydraulic system may be used.

It is therefor a general object of this invention to provide a system for regulating access to a material storage area.

Another object of this invention is to provide a system, as aforesaid, which presents a safety barrier across the material storage area when access thereto is not desired.

A further object of this invention is to provide a system, as aforesaid, wherein the barrier is movable from a closed position to an open position upon a desired entry of a material handler into the material storage area.

Still another object of this invention is to provide a system, as aforesaid, wherein a control system regulates barrier movement, the control system being regulated by the presence and absence of a material handler relative to the material storage area.

A further object of this invention is to provide a system, as aforesaid, the control system being responsive to the approach of a material handler in the form of a material handling device, e.g., a forklift or the like.

Another object of this invention is to provide a system, as aforesaid, wherein an alarm warns of barrier movement to the open position.

A particular object of this invention is to provide a system, as aforesaid, which precludes barrier damage during movement.

A still further object of this invention is to provide a system, as aforesaid, which can be adapted for manual operation.

Another particular object of this invention is to provide a system, as aforesaid, which provides a controlled speed and pressure to move the barrier to an open or closed position.

A further object of this invention is to provide a gate system, as aforesaid, which utilizes a plurality of adjacent paired gates for controlling access to a plurality of adjacent material storage areas with adjacent gate pairs being operable by a common control system.

A particular object of this invention is to provide a gate system, as aforesaid, which is adaptable for use along a zone of access of a material storage area whether located on a ground floor or on a mezzanine level or both.

Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings, wherein is set forth by way of illustration and example, a now preferred embodiment of this invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of the system showing a plurality of adjacent gate pairs for controlling access to adjacent material storage areas and diagrammatically illustrating the combination of gate pairs with the alternating master gates and slave gates; [0017]
FIG. 2 is a view on an enlarged scale showing the structure associated with side-by-side master gates as mounted at one master gate station; [0018]
FIG. 3 is a view on an enlarged scale showing the structure associated with side-by-side slave gates as mounted on a slave gate station; [0019]
FIG. 4 is a side view of the FIG. 3 structure showing structure associated with side-by-side slave gates as mounted on a slave gate station. [0020]
FIG. 5 is a block diagram of the electro-pneumatic control system flow. [0021]

DESCRIPTION OF THE PREFERRED EMBODIMENT

Turning more particularly to the drawings, FIG. 1 shows a first closed pair of [0022] gates 100 and an adjacent second open pair of gates 200 along the front edge 1010 of a mezzanine 1000 floor. Each pair of gates spans/fronts the width of a material storage area at the closed, horizontal position, such width being designated as a zone of access to the material storage area beyond the gates. Adjacent to the open gate pair 100 is shown a closed gate pair 200 as well as one closed gate 50 adjacent the open gate pair 100. An open gate 60 is also shown adjacent to closed gates 200. Each adjacent gate pair 100, 200 is controlled by a gate control system 500 mounted on a master support station 502 m as activated by a respective sensor 508, 508′. The control system 500 structure at a master support stand controls the operation of a master gate 100 m and slave gate 100 s of gate pair 100 as well as master gate 200 m and slave gate 200 s of the adjacent gate pair 200. Slave gates are so designated as they are mounted to support stands 502 s which do not have the control system 500 apparatus mounted thereon. Thus, each slave gate 100 s, 200 s is operated along with its master gate 100 m, 200 m. As such, alternating master (m) and slave (s) stations are utilized as diagrammatically shown in FIG. 1.
The master gate stand [0023] 502 m presents framework for support of a portion of the control system 500 apparatus as shown in FIGS. 1 and 2. The system for each gate pair includes sensors 508, a common control box 510, a solenoid control valve 520, a down pressure regulator 530 and two cylinder/piston assemblies 560 a, 560 b. Air line 570 and branches 570 a, 570 b, 572 and branches 572 a and 572 b controlled by a solenoid valve 520, communicate cylinders 560 a, 560 b with an air supply 590. Accordingly, air flow along line 570 and branches 570 a, 570 b communicate air from air supply 590 to the cylinder/piston assemblies 560 a, 560 b so as to extend piston rods 562 a, 562 b from a first retracted to a second extended position. Exhaust air is communicated through branches 572 a, 572 b and air line 572 to solenoid valve 520 to allow the air in cylinders 560 a, 560 b and against one side of piston head 563 to be exhausted to atmosphere 591 allowing for movements of piston rods 562 a, 562 b to this second extended position.
[0024] Line 572, regulator 530, and branches 572 a, 572 b, controlled by a solenoid valve 520, also communicate cylinders 560 a, 560 b with air supply 590. Accordingly, air flow along line 572, through regulator 530 and branches 572 a, 570 b communicate air from air supply 590 to the cylinder/piston assemblies 560 a, 560 b about an opposed side of the piston head 563 so as to move piston rods 562 a, 562 b from a second extended position to their first retracted position. Concurrently, exhaust air is communicated through branches 570 a, 570 b and air line 570 to solenoid valve 520 where displaced cylinder air is exhausted to atmosphere 581.
At a master support station [0025] 502 m, each gate 100 m, 200 m is pivotally mounted about a common shaft 580 horizontally extending through a support strut 592. Likewise, the gates 100 s, 200 s at the adjacent slave support stand 502 s are pivotally mounted about a common shaft 580′ extending through strut 592′.
Operation of the electro-[0026] pneumatic control system 500 for a respective gate pair, e.g., 100, is controlled by sensors 508 m and 508 s which are mounted below the mezzanine edge of the material storage area and below the master 502 m and slave 502 s gate station for the intermediate gate pair. The sensors 508 m and 508 s send out signals which are returned in response to a portion of the material handler, e.g., a telescopic forklift mast, upon fronting the zone of access which contains sensors 508 m and 508 s. Upon sensing the forklift mast the sensor 508 m and/or 508 s initiates gate operation by a signal to the control unit 510 which sends an electrical control signal to the respective solenoid valve 520. Valve 520 which normally exhausts line 570 to atmosphere 591 is energized so as to allow air flow through air inlet line 570 and along the air inlet branches 570 a, 570 b. Concurrently, valve 520 exhausts air flow through branches 572 a, 572 b and lines 572 to atmosphere. As such the pressurized air flow into the respective cylinders 560 a, 560 b against piston head 563 moves the respective piston rods 562 a, 562 b to their extended positions so as to open the gate 100 m, 100 s connected thereto. The open gates allow access to the material storage area. Concurrently, an alarm 568, e.g., flashing light, at support stand 502 m is energized indicating that a gate pair is open. Upon removal of the material laden pallet from the storage area and withdrawal of the forklift mast the sensor, lacking a stimulus, ceases delivery of the control signal to the control unit 510. Lacking a signal the solenoid valve 520 de-energizes and spring returns to its normal position which reverses the air flow paths, i.e., air enters the respective cylinder through air paths 572 a, 572 b with exhausted air flowing from the cylinders through paths 570 a, 570 b. This action returns rods 562 a, 562 b to their retracted position, resulting in movement of the previously open gates 100 m, 100 s to their horizontal closed position.
During gate movement from their open to the closed position, a [0027] pressure regulator valve 530 on air line 572 limits the pressure applied to rod side of 563 a and 563 b. This action allows the gates to close with a limited force such that the gate forces applied atop any objects that may be below the respective closing gate, e.g., boxes, workers, etc., would not be harmful. Two internal cylinder air cushions 599 at the ends of the cylinders further dampen gate opening and closing so as to avoid wear and tear. Bumper posts 578 protect the cylinder assemblies from contact with objects that could cause damage to the cylinder.
Likewise, if the material handler fronts the adjacent storage area controlled by [0028] gates 200, sensor 508 m′ and/or 508 s' sends a signal to the common control box 510 which activates solenoid valve 520′. The subsequent action is indicated by a dotted line path in FIG. 5 which likewise controls gates 200 s, 200 m as control of gates 100 s, 100 m has been above described. Thus, a gate pair will open only when activated by their respective sensors. Thus, controls for two gate pairs may be mounted on one master support stand which reduces the cost of installation as utility termination ports are minimized.
Although an [0029] ulatrasonic sensor 508 producing sound waves to respond to a telescoping forklift mast has been disclosed, other types of sensor may be used for the same purpose such as a photo sensor or proximity sensor. It is preferred that the sensor 508 be located below the elevated mezzanine deck 1000 so as to be responsive to the telescopic mast of the forklift. As such, a sensor 508 will provide a control signal only when the telescopic mast of the forklift has been elevated to the mezzanine level indicative of a desired entry of the forklift into the material storage area. Accordingly a gate pair will open only when the forklift wishes to positively access the elevated material storage area, as indicated by raising the forklift mast, and not by merely driving by the area. Thus, the barrier will remain at its closed safety position when access by the material handler is not desired. Also, the pneumatic means for moving the gates between their closed and open positions may be replaced with equivalent hydraulic means or electric motors which control linkage arms connected to the respective gates 100 m, 100 s. The gates may use equivalent structure so as to be mounted about vertical axis such that the gate movement is a swinging movement other than a pivotal one.
Also, my gate system could be adapted to be a manually assisted gate. For example the [0030] master control system 500 is not required, and the cylinder assemblies 560 a, 560 b are replaced with gas springs for a gate pair adapted for manual assisted operation. Gas springs greatly reduce the manual force required to open or close the gate. The gas springs will open/close automatically when manually moved more than 50% of the desired direction of travel similar to the action of a gas spring assisted hatchback of some automobiles.
Finally, although my system shows a preferred use on the mezzanine level, my system may be used on a ground floor so as to regulate access thereto. [0031]
It is to be understood that while certain forms of this invention have been illustrated and described, it is not limited thereto, except in so far as such limitations are included in the following claims and allowable equivalents thereof. [0032]

Claims

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. For use with a material storage area having a material support surface presenting a zone of access for passage of the material therethrough, a barrier system for the material storage area comprising:

at least one gate having a length adapted for spanning a length of the zone of access;

means for mounting said at least one gate in movement between a first closed position adapted for spanning a length of the zone of access and a second open position, said at least one gate first position precluding passage of the material through the zone of access and said second open position displaced from the zone of access to allow passage of the material through the zone of access;

means for automatically moving said at least one gate from said first to said second position upon sensing a desired entry of a material handler through the zone of access and a moving of said at least one gate from said second to said first position upon sensing a withdrawal of the material handler from the zone of access.

2. The system as claimed in claim 1 wherein said mounting means comprises:

support structure extending from the support surface;

means for fastening said at least one gate to said support structure in said movement between said first and second positions.

3. The system as claimed in claim 2 wherein said at least one gate movement is a pivotal movement between said first and second gate positions about an axis extending through the support structure.

4. The system as claimed in claim 1 wherein the material handler is a mast of a forklift fronting the zone of access.

5. The system as claimed in claim 1 wherein said moving means includes:

a piston rod having a first end and a second end, said second end attached to said at least one gate;

means for reciprocating said rod in movement between first and second positions, said rod at said first position urging said at least one gate connected thereto to said first closed position with said rod at said second position urging said at least one gate connected thereto to said second open position.

6. The system as claimed in claim 5 wherein said reciprocating means comprises:

a cylinder including said first piston rod end therein;

air delivery means for controlling delivery of air relative to said cylinder, a delivery of said air to said cylinder urging said rod to said first or second positions.

7. The system as claimed in claim 5 wherein said at least one gate comprises first and second gates spanning the length of the zone of access and said moving means includes:

a pair of piston rods each having a first end and second end, said second end of each rod attached to a respective gate;

means for reciprocating said rods in movement between first and second positions, said rods at said first position urging said connected gates to said first closed position with said rods at said second position urging said connected gates to said second open position.

8. The system as claimed in claim 6 wherein said air delivery means comprises:

an air source;

first and second air flow paths between said source and said cylinder;

valve means movable first and second positions for alternating an air flow through said first or second air paths and into said cylinder, said valve at said second position allowing an air flow through said second air path for moving said rod to said second position with said valve at said first position allowing air flow through said first air flow path for moving said rod to said first position;

means for controlling said positions of said valve means, said valve control means responsive to the desired entry of a material handler through the zone of access to move said valve means to said second position and a withdrawal of the material handler from the zone of access to move said valve means to said first position.

9. The system as claimed in claim 8 wherein said valve control means includes at least one sensor, said at least one sensor moving said valve to said second position upon a material handler fronting the zone of access and said first position upon a withdrawal of the material handler from the zone of access.

10. The system as claimed in claim 9 wherein said valve means comprises:

a solenoid valve responsive to a control signal to allow for flow of said air through said first air path and into said cylinder while allowing exhausting air in said cylinder through said second air flow path, said valve responsive to a lack of said control signal to reverse flow of said fluid through said first and second air flow paths and allow an air flow through said second air flow path into said cylinder and exhaust of air from said cylinder along said first air flow path and wherein said control means for said valve means comprises:

sensor means for producing said control signal to said valve, said sensor means responsive to the desired entry of the material handler to the zone of access to produce said control signal and ceasing the control signal upon the withdrawal of the material handler from the zone of access.

11. The system as claimed in claim 1 wherein the material support surface is a raised mezzanine surface displaced from a ground floor surface, the zone of access along a front of the mezzanine, said moving means positioned under the mezzanine deck and sensing the desired entry and withdrawal of the material handler on the ground floor therebelow.

12. For use with a material storage area having a material support surface presenting a zone of access, the zone of access for insertion and withdrawal of the material therefrom, a barrier system for the material storage area comprising:

means for mounting said gate in movement between a first closed position precluding passage through the zone of access and a second open position for allowing passage through the zone of access;

control means including a sensor for automatically moving said at least one gate to said second open position upon said sensor identifying a presence of a material handling device adjacent the zone of access and to said first position upon said sensor identifying a withdrawal of the material handling device from the zone of access, said at least one gate first position further precluding passage of a material handler beyond the material storage area.

13. The system as claimed in claim 12 wherein said at least one gate movement is a pivotal movement between said first and second positions.

14. The system as claimed in claim 12 wherein the material support area is a mezzanine surface elevated from a ground floor surface with said sensor below said mezzanine surface, said zone of access being a front of the mezzanine elevated from said ground surface, said sensor of said control means adapted for response to the material handling device on the ground floor below the elevated mezzanine.

15. The system as claimed in claim 14 wherein the material handling device is a forklift, said sensor of said control means sensing the presence and absence of a portion of the forklift below the mezzanine front.

16. The system as claimed in claim 12 wherein the material storage area comprises a plurality of laterally adjacent material storage areas, each area having said barrier system thereon.

17. For use with a material storage area on a mezzanine having a raised material support surface relative to a ground floor and presenting an elevated edge, a barrier for precluding passage beyond the mezzanine edge comprising:

at least one gate;

means for mounting said at least one gate between a first closed position wherein said at least one gate spans a length of the mezzanine edge and a second open position displacing said at least one gate from the mezzanine edge;

means for moving said at least one gate by a material handler on the ground floor between said first position restricting passage beyond the mezzanine edge and said second open position allowing passage of material from beyond the mezzanine edge and into the material storage area.

18. The system as claimed in claim 17 wherein said at least one gate comprises a pair of gates, said pair of gates at said first position combining to span the entire length of the edge.

19. The system as claimed in claim 17 wherein said movement of said at least one gate is a pivotal movement between said first and second positions.

20. The system as claimed in claim 17 wherein said mounting means includes automatic control means for moving said at least one gate to said open position upon a material handling device being sensed adjacent the zone of access and to said closed position upon sensing a displacement of the device from the zone of access.