"Door Holder"

Technical Field

This invention relates to door holders and in particular to door holders for use in vehicles and the like.

Background Art

In a number of prior art applications/ it has been found desirable to hold a door in an open position notwithstanding substantial forces acting on the door tending to swing it from the open position. One ex¬ ample of such an application is that of the door for a cab of a vehicle, such as an earthworking vehicle.

In the normal use of such earthworking vehi- cles, such as tractors, etc., the cab may be air condi¬ tioned. It has been found, however, that the operator may prefer to operate the vehicle with the air condi¬ tioning apparatus de-energized such as during temper¬ ate weather conditions. At s ^' uch times, the operator may ventilate the cab by opening the cab door and various means have been provided for maintaining the door in the open position during such use.

One excellent example of a. door holding means for such use is illustrated in U. S. Letters Patent 4,035,016 of John S. Ricca, which patent is owned by the assignee hereof. The apparatus for holding the door in the open position includes a crank having a handle and an eccentric arranged to hold the door against a stop. The structure includes a resilient linkage and means for limiting rotation of the crank to allow an over center action whereby the resilience of the linkage provides a firm holding of the door against the stop.

In another form of prior art structure for hold¬ ing a door in an open position, catch mechanisms are provided at ^" che top and bottom of the door. However, at times, relative motion occurs between the cab and the platform so as to cause twisting of the door held by the catches.

Disclosure of Invention

The present invention comprehends an improved means for holding a door in an apparatus, such as a vehicle, which is simple and economical of construc¬ tion and which provides facilitated selective position¬ ing thereof between retracted and door holding disposi¬ tions.

In one more specific aspect of the invention, the door holding means comprises a blocking element which is swingably mounted to the wall means defining the door opening so as to be selectively disposed across the opening to hold the door in the open posi¬ tion, or in a retracted position wherein the element hangs downwardly on the wall means.

In the illustrated embodiment, the elongated door blocking element comprises a rod which is pivot- ally mounted to the door frame by a pivot having a horizontal axis. The portion of the blocking element engaging the door defines a holding means at the op¬ posite end of the blocking element.

The holding means may be pivotally connected to the blocking element so as to be pivotal about a vertical axis when the blocking element is disposed to hold the door open.

The invention further comprehends the provi¬ sion of means spaced from the blocking element for re¬ leasing the holding means to permit the blocking ele¬ ment to return to the retracted position as by gravity.

The holding means may comprise magnetic means and in the illustrated embodiment, comprises electro¬ magnetic means.

Energization of the electromagnetic means may be controlled by one or more switches. In the illus¬ trated embodiment, one of the switches is arranged to be actuated as an incident of operation of the door handle.

A second of the illustrated door switches is arranged to be manually operated as desired.

In the specific illustrative embodiment, an electromagnet is mounted on the door and a magnetic plate is pivotally mounted to the distal end of the blocking element rod. The rod normally hangs down- wardl with the magnetic plate lowermost. When the user wishes to hold the door in the open position, he need merely swing the rod to extend across the door opening so as to bring the plate into engagement with the electromagnet, whereupon energization of the elec- tromagnet retains the blocking element suitably to maintain the door in the open position notwithstanding substantial forces being exerted thereon as in the operation of the vehicle in which the door structure is mounted. in the illustrated embodiment, the switch, oper¬ able as an incident of operation of the door handle, is a proximity switch.

The door holding structure of the present in¬ vention, thusly, is extremely simple and economical of construction while yet providing a positive selective retention of the door in the open position when desired.

Brief Description of the Drawings

FIGURE 1 is a fragmentary side elevation of a vehicle having a cab provided with a door structure

including means for selectively holding the door in an open position embodying the invention;

FIGURE 2 is a fragmentary elevation illustrat¬ ing the arrangement of the door holding means arranged to hold the door in the open position;

FIGURE 3 is a fragmentary elevation of a por¬ tion of the door structure including a portion of the door holding means; and

FIGURE 4 is a schematic wiring diagram of the electrical circuit of the door holding means.

Best Mode for Carrying Out the Invention

In the exemplary embodiment of the invention ^~ as disclosed in the drawing, a door structure gener¬ ally designated 10 is shown to include wall means 11 defining an opening 12, and a door 13. A hinge 14 defines means for mounting the door for swinging move¬ ment between a closed position, as shown in Figure 1 of the drawing, wherein the door extends across the opening 12, and an open position, as shown in Figure 2 of the drawing, wherein the door is arranged to pro¬ vide passage through the opening.

As illustrated in Figure 1, door structure 10 is advantageously adapted for use in a cab generally designated 15 of a vehicle 16, such as an earthworking vehicle or the like. The cab defines an operator's space 17 wherein the operator of the vehicle normally is disposed for effecting operation thereof. As dis¬ cussed above, at times, the operator of the vehicle may wish to open the door and hold it in the open position during operation of the vehicle. The present inven¬ tion comprehends an improved door holding structure generally designated 18 for effecting such door reten¬ tion.

More specifically, as illustrated in Figures

2 and 3, door holding structure 18 includes a blocking element 19 which may comprise an elongated rod having a mounting portion 20 at one end of the rod swingably mounted to a portion 21 of wall means 11 at the side of opening 12 opposite the disposition of hinge 14. In the illustrated embodiment, the mounting portion is pivotally mounted to swing the rod 19 about a hori¬ zontal axis 22 extending perpendicularly outwardly from the wall portion 21 so as to permit swinging of the ^" rod 19 from a vertically downwardly extending retracted disposition, as illustrated in Figure 1, and a hori¬ zontally extending blocking disposition, as shown in Figure 2.

As the center of gravity of the blocking ele- ment is spaced from the pivot portion 20, the blocking element is normally biased to the downwardly extending disposition of Figure 1 by gravitational biasing. As shown in Figure 1, in the retracted disposition, block¬ ing element 19 extends substantially directly down- wardly below a grasping handle 23 fixedly mounted to the wall means 11.

In the door blocking disposition of Figure 2, the blocking element effectively extends across the opening 12 to have the distal portion 24 thereof juxtaposed to the opened door remotely of hinge 14 to effectively block movement of the door from the open position. To maintain the blocking element in the door blocking position, a holding means generally des¬ ignated 25 is provided on the blocking element end por- tion 24 and on the confronting portion 26 of door 13. More specifically, as illustrated in Figures 2 and 3, the holding means includes a clevis 27 defining the distal end of the blocking element, and a support 28 swingably mounted to the clevis by a pivot pin 29. As shown in Figure 2, the axis 30 of pivot pin 29 extends

vertically when the blocking element 19 is arranged in the door blocking position of Figure 2, thus per¬ mitting the support 28 to swing about the vertical axis and suitably position a magnetic plate 31 to have facial engagement with a plate 32 of an electro¬ magnetic device 33 carried by the door portion 26. As illustrated in Figures 2 and 3, the electromagnetic device 33 may be secured to the door portion 26 by suitable screws 34. Door 13 is further provided with a latching mechanism generally designated 35 including an inner operating handle 36, as shown in Figures 2 and 3, and an outer operating handle 37, as shown in Figures 1 and 3. Energization of the electromagnetic device 33 is controlled by a first switch 38 illustratively com¬ prising a proximity switch disposed adjacent inner handle 36, as shown in Figure 3, and a manually oper¬ able switch 39 mounted on door 13 adjacent switch 38. As illustrated in Figure 4, coil 40 of the electro¬ magnetic device 33 is connected in series with the proximity switch 38 and manually operable switch 39. The coil may be connected through an oil pressure switch 41 and a suitable protective fuse 42 to one side of the vehicle battery B, switch 39 being con¬ nected to the other side of the battery through a ground connection G. Thus, energization of coil 40 requires that the engine be running so as to provide positive oil pressure to close switch 41 and concur- rent closing of switches 38 and 39. As discussed above, switch 38 may comprise a proximity switch and is disposed adjacent handle 36 so as to be closed as an incident of movement of the handle to the released disposition of Figure 3. Switch 39 may include an operating handle 43 for selectively closing the single

λr

throw switch, as shown in Figure 4, to complete the circuit for energizing coil 40.

Thus, it may be seen that when it is desired to de-energize the coil so as to release the door hold- ing means, the user selectively may operate the manual¬ ly -.operable switch 39 or may simply manipulate the door handle 36 so as to displace the door, handle from the proximity switch 38 whereby the switches are selec¬ tively opened, upon de-energization of the electro- magnetic device coil 40, the blocking element is free to swing downwardly by its gravitational bias back to the retracted position of Figure 1, thereby immediately permitting passage through the door opening 12 or clos¬ ure of the door 13, as desired. By mounting the pivot 22 on the door frame de¬ fined by wall means 11, the door holding means is ef¬ fectively mounted to the same portion of the cab struc¬ ture as that to which the hinge 14 is mounted, thereby effectively eliminating twisting strains on the hinge by the forces developed through the holding means.

The use of the electromagnetic magnetic hold¬ ing means 25 permits the disposition of the control switch 39 as desired. While the control switch is il¬ lustratively shown as being disposed adjacent the door handle 36, as will be obvious to those skilled in the art, it may be suitably located elsewhere as desired, such as at the instrument console within the operator' s station.

Thus, the improved, selectively blockable door structure of the present invention, as disclosed above, is extremely simple and economical of construction while yet providing an improved means for holding a door, such as the door of a vehicle cab in the open position while effectively preventing twisting stresses as developed by the prior art structures heretofore utilized for such door retention purposes.

Industrial Applicability

The door structure of the present invention is advantageously adapted for a wide range of indus¬ trial uses while being advantageously adapted for use in vehicle cab door structures as discussed above. The door structure advantageously utilizes an electromag¬ netic device for improved control of the door holding function. Thus, the improved door structure is advan¬ tageously adapted for industrial applications wherein remote control of the release of the door holding means may be desired.

The door holding structure of the present in¬ vention is further advantageously adapted for use in industrial applications wherein it is desirable to cause an automatic retraction of the door holding mechanism away from the access opening controlled by the door upon release of the holding mechanism. Such an improved arrangement is advantageously adapted for use in the illustrated vehicle application wherein free ingress and egress through the door opening is highly desirable. At the same time, the retracted disposition of the door holding means in the illus¬ trated embodiment is one wherein the holding mechanism is closely adjacent the door opening for facilitated manipulation by the user to the door blocking disposi¬ tion when desired.

Other aspects, objects and advantages of this invention can be obtained from a study of the drawings, the disclosure and the appended claims. The forego- ing disclosure of specific embodiments is illustrative of the broad inventive concepts comprehended by the invention.