Rear mounted operator restraint bar

Abstract: An operator restraint bar (20) for a working vehicle, specifically for a skid steer loader, is mounted on the rear wall of the cab (10) of the loader and is movable from a restraint position to a raised position with one end adjacent the roof of the cab. The restraint bar is mounted onto brackets (26, 28) that are self contained and include a spring for holding the bar in either its working position or its raised position by arranging the pivot points of the bar and the spring so that they go over center between the working and raised positions. A sensor is used at the pivot for indicating when the restraint bar has reached its working position.

Description: The present invention relates to loader operator restraint bars for mounting in skid steer loader cabs, wherein the bar is mounted on the rear wall and the front cross member moves upwardly to a non-restraint position and then downwardly to a position where it extends across the lap of an operator sitting on the seat. The restraint bar position can be sensed for use with an operating interlock for the loader such that when the restraint bar is raised, operation of at least some function of the loader is prevented. US-A-4397371 illustrates an operator restraint system which has a restraint member that is mounted at the forward side of an operator's cab, and is tied into a control system of the loader. Rear mounted restraint systems also have been utilized, for example, those shown in US-A-5050700 and US-A-5383532 GB-A-2 328 268 discloses a pedal locking device for a loader vehicle, comprising a vehicle body with a cab and a seat and hydraulically operated working implements, eg boom, bucket and attachment, which are controlled via a hydraulic control valve unit operated by respective pedals. A seat bar swings between a lowered position in which an operator is secured to the seat and a raised position in which the operator is released from the seat. The pedals can be locked in the neutral position by detent levers which engage dog plates attached to the pedals and are spring-biassed into the locking position. A Bowden cable interconnects the seat bar and the detent levers so that as the seat bar is lowered the pedals are unlocked and as the seat bar is raised the pedals are locked again. The existing rear mounted restraint bars are relatively complex in mounting, and a simplified, easily installed and easily operated restraint for an operator is desired. It is a further object of the present invention that the operator restraint forms a complete subassembly that can be made separate from the loader cab. These objects of the present invention are fulfilled by the features of claim 1. The dependent claims relate to further preferred embodiments of the present invention. The present invention relates to a rear mounted operator restraint bar or seat bar, that mounts on the rear wall of an operator cab of a skid steer loader, where the mounting is out of the way and leaves the front cab area unobstructed. The restraint bar is a U-shaped member that has a pair of mounting brackets for side legs on the rear wall, each with a self-contained spring. The bracket springs will urge the bar to a restraint position after it has been lowered near such position, and when lifted by the operator, will hold the bar is a release position so that the operator can move in and out of the cab. In the restraint position, one bracket of the restraint bar mounting can mount a sensor that will provide a signal indicating that the restraint bar is in a selected position, and couple the signal into a control system so that the loader drive and operating systems are disabled unless the restraint bar is down. In one aspect of the invention, a rear mounted operator restraint bar for a vehicle cab has a pair of side arms, with each of said side arms being mounted on a separate mounting bracket. A pivot connection is provided between the side arms and the respective separate mounting bracket. The mounting brackets have a mounting wall that is supported on the rear wall of the cab and a spring bracket is attached to at least one arm. A compression coil spring has a first end bearing against a portion of the spring bracket for applying a force at a first location and has an opposite end pivotally mounted on the associated mounting bracket at a pivot off-set from the pivot of an associated restraint bar arm. The pivot of the spring on the associated mounting bracket, the first location and the pivot connection of the associated arm pass over center when the restraint bar is moved from a working position to a raised position so the restraint bar then remains in its raised position. Various other serial interlocks can be used with the restraint bar sensor desired. Reference is made to the drawings in which: Figure 1 is a schematic side view showing a restraint bar made according to the present invention in a raised position in a cab of a skid steer loader and in its working position in dotted lines; Figure 2 is a fragmentary side elevational view of the restraint bar of the present invention in a working position; Figure 3 is a front elevational view of the restraint bar of Figure 2; Figure 4 is an enlarged view of the mounting bracket assembly on the left side of Figure 3; Figure 5 is an enlarged view of the mounting bracket on the right side of Figure 3; Figure 6 is a sectional view taken as on Line 6--6 in Figure 5; Figure 7 is a perspective view of the bracket on the left hand side of Figure 8; and Figure 8 is a perspective view of an assembled restraint bar made according to the present invention ready for installation as a unit into a skid steer loader; A cab 10 of a skid steer loader is of conventional design, and the skid steer loader on which it goes is also of conventional design. The cab, as shown, has the windows removed, but has the front end 12, and a rear wall 14. An operator's seat 16 is made for an operator, who will sit and operate controls of conventional design. An operator restraint bar or seat bar indicated generally at 20 as shown, is mounted onto the rear wall 14, so that it extends forwardly. The bar 20 is a generally U-shaped bar that has a forward cross member 21 that extends laterally across the lap of an operator sitting on the seat 16, and fore and aft extending side arms 23. The side arms 23 are bent and have generally uprightly inclined portions 24 that are mounted onto separate mounting bracket assemblies 26 and 28, respectively. Referring to Figures 3, 4 and 5, it can be seen that the bracket assemblies 26 and 28 are essentially the same, except being adapted for the right and left sides and the mounting bases can be interchanged. The mounting for the restraint bar itself is slightly different for the right and left sides. Each of the bracket assemblies has a generally U-shaped channel base 30 that is formed as a unitary channel having spaced apart legs 32 and 34, that extend forwardly from a base wall 36. A downwardly extending support tongue or wall 38 is integral with the base wall 36 (see Figure 7, for example) and is formed to provide a planar offset stop wall portion 40, and a leg 42 that is bent back toward the cab rear wall 14 and rests against the wall 14 when the bracket assemblies 26 and 28 are fastened in place with suitable bolts or cap screws indicated at 44, in Figures 1 and 2, for example. The laterally extending restraint bar cross member 21, the restraint bar side arms 23, and the lower parts 24 of the vertical or upright sections of the restraint bar are tubular, and are selected to be capable of absorbing energy from loads exerted when the operator tends to be moved under inertial forces. The operator also will use a conventional lap belt, which is not shown. The arm portions 24 are joined to flat bar pivot arms 48 that are used for pivotally mounting the restraint bar to the respective bracket assemblies 26 and 28 on pivot pins 49 that extend between the individual legs 32 and 34 of each of the bases 30. This can be seen in Figures 4 and 5, which show the difference in mounting for the right and left-hand bracket assemblies 26 and 28. In Figure 4 the pivot arm 48 is broken away to show that the pivot arms 48 have a large pivot opening that fits onto a bushing 50 that has a thrust flange 52 that rides against the leg 32 of the bracket assembly 28 on that side of the cab. A spacer 54 is used in connection with another bushing 56 to hold that pivot arm 48 against the leg 32 of the base 30. The spacers will positively position the pivoting section 48 of the restraint bar. A bushing 50 is also used on the pivot arm 48 shown in Figure 5, but the pivot arm on that side of the cab is held adjacent leg 34 of base bracket 30. Both pivot arms 48 are held adjacent the inside leg of their respective bases 30. A spring assembly 60 is mounted on each of the bracket assemblies. The spring assemblies include compression springs 60 having first ends supported on inwardly bent legs 62A and 64A on shield brackets 62 and 64 on the respective sides of the restraint bar. The compression springs 66 are mounted over sliding rods 68 using suitable bushings 70 at the opposite ends of the springs. The bushings 70 at the first ends of the springs 66 are supported on legs 62A and 64A. Each rod 68 has a clevis 72 at the respective second end, and each clevis is pinned with a pin 74 to one of the legs of the bases 30 of bracket assemblies 26 and 28. As shown in Figure 4, the clevis 72 for the spring 66 on that side of the restraint bar is mounted on the bracket leg 34, and as shown in Figure 5, the clevis 72 for the bracket assembly 26 is mounted on the leg 32 of that bracket 30. The upper bushing 70 of each adjacent the clevis 72 is anchored to the rod 68 so the spring force acts against respective leg 62A or 64A. The springs 66 are of length so that they will exert a force against the legs 62A or 64A tending to pivot the restraint base about the pivot pins 49. The shield brackets 62 and 64 are welded onto the respective pivot arm 48, and the position of the pin 74 for the clevis, the openings through which the rods 68 pass on the legs 62A and 64A, and the position of pivot pins 49 for the pivot arms 48 will determine how the loading from the springs will effect the pivoting of the operator restraint bar. The brackets 62 and 64 have stop flanges 79 bent down from the legs 62A and 64A and extending generally parallel to walls 40 of the bases 30 with the restraint bar in its lowered position. When the restraint bar is in the lowered position shown in Figure 2, the springs 66 will urge the operator restraint bar and stop flanges 79 joined to the inner ends of legs 62A and 64A of the shield brackets against a stop cushion 80 that is mounted on the offset stop wall 40 of the respective formed base 30. A stopped working position is assured. The operator restraint bar 20 is thus positively located in its working position. The force from the springs 66 urging the outer laterally expending portion 21 downwardly will result in the need for a lifting force at the outer end of the restraint bar, as indicated by the arrow 82 in Figures 1 and 2, of approximately 25 pounds, so that the restraint bar 20 will be held down in working position unless a positive force is used to lift the restraint bar so it pivots about its pivot pins 49. When the restraint bar 20 is in its raised position as shown in Figure 1, the effective mounting points of springs 66 have gone over center, and the clevis pin 74 is below the line between the pivot pin 49 for the restraint bar and the openings for rods 68 in the legs 62A and 64A that support the springs, so the springs 66 also act to hold the restraint bar 20 in its raised position. The springs 66 are selected so that the downward force to pull the restraint bar down from its raised position shown in Figure 1 is less than that needed to lift the bar, and it would be about 15 pounds. The brackets 62A and 64A have forward walls 62B and 64B that shield the springs 66 substantially, as shown in Figures 4 and 5, and protects them from damage, as well as shielding them from exterior members. It should be noted that the clevis pins 74 are supported on shouldered bushings 84 that have a flange that rides against the respective legs 32 or 34 of the bracket 30, and have a large diameter outer sleeve section that passes through a large opening in the respective bracket leg 32 or 34 to provide a greater surface area for pivoting and to support the springs on the relatively narrow legs 32 and 34 of the bases 30. The bushings 84 provide a larger surface area for operation, and are similar to the use of the bushing 50 for the pivoting arms 48. The bracket assembly 26 includes components for sensing the position of the operator restraint bar when it is in its lowered position, to provide an interlock signal that will enable operation of the loader only when the restraint bar is down. If the restraint bar is not in its lowered position, the loader cannot be operated. As can be seen in Figure 6, a Hall Effect sensor assembly 100 is mounted onto the leg or wall 32 of the base 30 forming part of the bracket assembly 26, and includes a part annular support frame 102 spaced from a rotating bushing 108 that rotates with the restraint bar about pivot pin 49. The frame 102 supports a circuit board 104 at a lower side, and the circuit board 104 has a Hall Effect sensor 106 that is positioned adjacent to the rotating bushing 108. The bushing 108 also serves as a spacer to bear on flange 52 for the bushing 50 on bracket assembly 26. The pivoting arm 48 on bracket assembly 26 is thus held adjacent leg 34 of that base 30. The bushing 108 is keyed so it will turn with the pivot arm 48 on that side of the restraint bar. The bushing mounts a pair of magnets 110 that will move arcuately as the restraint bar pivots to its raised position, so the magnets 110 become spaced a greater distance from the Hall Effect sensor 106 than when the bar is in its lowered position as shown in Figure 6. When the restraint bar 20 is in the lowered position, the magnets 110 will affect the Hall Effect sensor 106 in a known manner and a signal will be provided to an interlock circuit 112. The signal that the restraint bar is in its lowered position will arm the interlock circuit with a signal indicating that at least one of the conditions for operation of the loader has been met. If there are other inputs to the interlock circuit, such as a sensor to sense that an operator is seated in the seat 16, those signals also have to be in the proper state for operation of the loader. When the restraint bar is raised, however, the magnets 110 are spaced from the Hall Effect sensor 106 and the lack of a signal to the interlock circuit 112 will lock up the loader operational functions so that the loader cannot be moved, and the boom or bucket or whatever other implement is on the loader cannot be operated until the restraint bar is moved to its working, lowered position. Additional inputs to the interlock circuit can also be an operator energized switch that would have to be pushed after the operator was sitting in the seat, or similar interlock functions. The individual bracket assemblies 26 and 28 can be preassembled onto the operator restraint pivot bars 48, and thus the operator restraint forms a complete sub-assembly that can be made separate from the loader cab and other portions of the loader, as shown in Figure 6, and then merely bolted in place on the loader as a unit. Figure 8 shows the finished sub assembly wherein the restraint bar 20 is covered with a suitable foam padding indicated at 120. The foam padding also will cover the shields or flanges 64B and 62B of the spring brackets 62 and 64. Thus, the bracket assemblies are easily made, and provide positive positioning of the restraint bar in raised and lowered positions, as well as ensuring that the installation is done with a minimum of time by having the ability to pre-assemble the brackets and the seat bar. The use of a mechanical (coil) spring and the formed spring mounting bracket makes the operation very reliable. It should also be noted that a single bracket can be used if the restraint bar has one reasonably extending arm on one side of a cross or lap bar, so the restraint is L-shaped. Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.

Claims: A rear mounted operator restraint bar (20) for a vehicle cab (10) having a rear wall (14), the restraint bar (20) being U-shaped and having a pair of side arms (23), each of said arms (23) being adapted to be pivotally mounted relative to a cab (10), a pivot (49) for pivotally mounting the arms (23) relative to the cab (10), a spring (66) pivotally mounted between the cab (10) and the restraint bar (20) at pivot points (74, 62A, 64B) positioned such that one spring pivot (62A,62B) passes over center when the restraint bar (20) is moved from a working position to a raised position, to provide a force urging the restraint bar (20) to remain in the working position and also remain in the raised position, respectively, after raising the restraint bar (20) a selected amount, characterized by mounting brackets (26, 28) and having a mounting wall (36), and the restraint bar (20) being pivotally mounted on a respective mounting bracket (26, 28), and the spring (66) being pivotally mounted at one end at a first spring pivot (74) to one of the mounting brackets (26, 28), and at an opposite end (62A, 62B) to the restraint bar (20). The rear mounted operator restraint bar of claim 1 further characterized by the spring (66) comprising a compression coil spring (66), and the pivot connection (62A,62B) to the restraint bar (20) supporting the compression coil spring (66). The rear mounted restraint bar of either of claims 1 or 2, further characterized by each of said mounting brackets (26,28) comprising channel shaped-brackets having side legs (32,34) and the mounting wall (36) of each bracket (26,28)comprising a base wall (36)that rests against the rear wall (14) of the loader cab (10), each of the mounting brackets (26,28) having a first side leg (32,34) that is positioned toward an adjacent lateral side of the loader cab (10), and a second side leg (32,34) spaced inwardly from the first leg (32,34), and the arms (23) of the restraint bar (20) being pivotally mounted to the second leg (32,34) of the respective mounting bracket (26,28). The rear mounted restraint bar of claim 3, further characterized by the pivotal connection (74) of the spring (66) to the associated mounting bracket (26,28) is a connection to the first leg (32,34) of the associated mounting bracket (26,28). The rear mounted restraint bar of any of the preceding claims, further characterized by at least one of the restraint bar arms (23) having a sensor (100) for sensing a position of the restraint bar (20). The rear mounted restraint bar of any of claims 1-5, further characterized by said mounting walls (36) of the mounting brackets (26,28) extend in direction along portions of the arms (23) of the restraint bar (20), and stop members (40) formed on said mounting wall (36) for engaging the arms (23) of the restraint bar (20) when the restraint bar (20) is in a working position. The rear mounted restraint bar of claim 5 or 6, further characterized by said sensor (100) comprising a Hall Effect sensor including a first portion (106) and a second portion (110), the first portion (106) being mounted on a sensor bracket (102) adjacent the pivot (49) of the at least one operator restraint bar arm (23) and the other portion (110) of the Hall Effect sensor being mounted for movement about the pivot (49) of the at least one restraint bar arm (23) when the restraint bar (20) is pivoted. The rear mounted restraint bar of any one of claims 1-7 further characterized by a restraint bar sub-assembly formed with the mounting brackets (26,28), springs (66), stop members (40) and restraint bar (20), said sub assembly being adapted to be installed directly on the rear wall (14) of the cab (10).

Inventors: BARES MARK F, BARES, MARK F.
Applicants: CLARK EQUIPMENT CO
Application year: 2000
Main classification: B60R21
IPC codes: B66F9, E02F9, B60R21