Low profile vehicle restraint

Details Low profile vehicle restraint Low profile vehicle restraint

2000-02-23

2001-11-27

Bratlie, Steven A. (Department: 3652)

Material or article handling

Load-transporting type vehicle and external means...

Means serves to align wheeled vehicle and load receiving or...

Reexamination Certificate

active

06322311

ABSTRACT:

I. BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an improved system for restraining a vehicle such as a transport truck or trailer which is to be restrained from movement at a loading dock. This invention is also related to a sensing system for use with such a vehicle restraint.
2. Prior Art
A variety of techniques are known by which a vehicle is mechanically secured to prevent movement by using the ICC bar as the means to engage the truck or trailer. U.S. Pat. No. 4,127,856 Bickel describes the use of electrical switches to sense the engagement of the vehicle restraint with a bar mounted on the rear of a vehicle. The commercial use of locking devices is now well known in the art. For example, the Rite-Hite “Dok-Lok”, Serco “VR” and Kelley “Truk Stop” and “Star” all have models that contact a vehicle ICC bar and constrain the truck from movement. Models of those systems generate signals to indicate that engagement has occurred so that personnel at the loading dock have an audible/visual indication of locking.
These techniques are mentioned or described in many U.S. Patents including, U.S. Pat. Nos. 4,267,748; 4,282,621; 4,488,325; 4,553,895; 4,692,755; 4,695,216; 4,759,678; 4,830,563; 4,843,373; 4,938,647; and 4,946,330.
One characteristic of previous ICC bar engagement devices is that the system had limits of engagement known as an “operating envelop”. The ICC bar, by previous Governmental regulation could not be higher than 30 inches off the ground. This formed the upper limit of the operating envelop. The lower limit is not defined by regulation but determined as a function of trailer manufacturer (as is the case of the shape of the ICC barrier itself) and the degree of float of the truck as it is loaded and unloaded. Typically the lower limit was approximately 15 inches. Consequently, the operating envelop required that the vehicle restraint not only capture the ICC bar within that range but also have the ability to follow vertical movement as the vehicle “floated” during loading operations to maintain engagement. Moreover, the restraint has to lower and disengage from the ICC bar when the bar itself is at the lower end of the envelop or else the vehicle will remain constrained while loaded and ready to depart from the dock.
Contemporary designs for trailers are lowering the ICC bar clearance from the ground to about 10 inches. Prior systems due to mechanical configuration cannot operate within an envelop from 10 to 30 inches. The configuration of the devices even in the lowermost position project above 10 inches, whether track mounted or surface mounted. This will not allow them to engage, restrain and disengage a vehicle ICC within the totality of the contemporary operating envelop.
Thus a need currently exists for a vehicle restraint having the desirable characteristics of commercial devices but with an extended operating range.
Systems in use have electrical switches which generate a signal by the presence or absence of physical contact with a moving part. A switch senses a change in the position of a component of the restraining device. The switch does not directly sense the presence or absence of the bar mounted on the rear of a vehicle. While such systems generally function well, and provide useful information to the control system, there are two major deficiencies in all of the previous systems. First, the loading dock area and the rear end of trailers can be very harsh environment as a result of rain, snow, ice, road salt and other materials present at a loading dock. These devices use mechanical limit switches which have moving parts which can become corroded or made inoperative by ice, dirt or other debris. Even if the limit switch is an inductive proximity switch, it is still activated by the motion of a mechanical component of the restraining device, and are therefore is subject to malfunction or false signal if one of the moving components should become broken or stick from corrosion or other foreign matter. Consequently a need still exists in the art for improved sensing techniques, especially as the operating range of the restraint increases.
II. SUMMARY OF THE INVENTION
This invention, in a first preferred embodiment is directed to a low profile vehicle restraint. This invention employs the essential linkage of previous designs to enable the restraining hook to move in a vertical direction thus minimizing the degree to which the vehicle may move away from the loading dock. This embodiment however represents a departure by not fixing the geometry of the linkage so that the operating range may be extended.
In accordance with this invention the vehicle restraint comprises a frame mountable relative to a dock face and a linkage mounted to the frame about one pin. The linkage has a member movable with respect to the frame at a position spaced from the pin. The linkage moves a restraining structure in a vertical manner between a stored position and a restraining position as the member shifts position relative to said frame.
The frame further comprises a ramp surface and the member comprises a roller moving on the ramp surface. Sliding contact may also be employed if the frictional forces are not significant.
The linkage comprises a first arm pivotally connected to the frame, a second arm pivotally connected to the first arm and having the member, rolling or sliding, attached at a first end movable with respect to the frame. A second end is pivotally coupled to the restraining structure, and a third arm couples the first arm to the restraining structure to maintain the restraining structure in a generally vertical orientation. The second arm further comprises a flange section forming a top cover for the housing when said restraint is in a lowered stored position.
A gas spring biases the linkage in an upward position. Also, a powered mechanism may be employed to raise and lower said linkage and said restraining structure.
The vehicle restraint may also employ a sensor carried by the restraining structure to determine engagement with a vehicle. The restraining structure comprises a vertical member coupled to the second arm, and a horizontal member pivotally coupled to vertical member. The sensor comprises a proximity switch carried by said horizontal member.
The vehicle restraint of this invention may also use a restraining structure comprising a rigid hook and said sensor is embedded in said hook. Thus, in accordance with another preferred embodiment of this invention the sensor structure is completely embedded within a sensor bar that moves in response to contact with the vehicle. As a result issues of cost of multiple sensors, sensitivity and placement of the sensors are eliminated. Further, in accordance with the broader aspects of this invention exposure and potential damage of the sensors or plates is also eliminated.
This invention will be described in greater detail by reference to the attached drawing and the description of the preferred embodiments that follow.


REFERENCES:
patent: 4674941 (1987-06-01), Hageman
patent: 4915568 (1990-04-01), West
patent: 5203663 (1993-04-01), Ruppe
patent: 5346353 (1994-09-01), Alexander

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