US2911232A - Overhead guard for industrial lift truck - Google Patents

Description

Nov. 3, 1959 R. HASTINGS, JR ETAL 2,

OVERHEAD GUARD FOR INDUSTRIAL LIFT TRUCK Filed April 22, 1957 5 Sheets-Sheet l INVENTORS. g RUSSELL HASTINGS JR. 3', HARRY A. MACKlE JOHN M SQUIER 1959 R. HASTINGS, JR ETAL 2,911,232

OVERHEAD .GUARD FOR INDUSTRIAL LIFT TRUCK Filed A r l 22, 1957 5 Sheets-Sheet 2 INVENTORSS RUSSELL HASTINGS JR. HARRY A. MACKIE JOHN M. SQUIER BY M y ATTY.

1959- RQ HASTINGS, JR ET'AL 2,911,232

OVERHEAD GUARD FOR INDUSTRIAL LIFT TRUCK- Filed April 22, 1957 5 Sheets-Sheet 3 INVENTORS. RUSSELL HASTINGS JR. HARRY A. MACKIE BYJOHN M. SQUIER ATTY.

NOV. 3, 1959 s'n s, JR EI'AL 2,911,232

OVERHEAD GUARD FOR INDUSTRIAL LIFT TRUCK Filed April 22, 1957 5 Sheets-Sheet 4 INVENTORS.

RUSSELL HASTINGS JR.

HARRY A. MACKIE JOHN M. SQUIER BY ATTY.

1959 R. HASTINGS, JR ETAL 2,911,232

OVERHEAD GUARD FOR INDUSTRIAL LIFT TRUCK Filed April 22, 1957 5 Sheets-Sheet 5 INVENTORS. RUSSELL HASTINGS JR.

MACKIE SQUIER HARRY A. JOHN M.

'ATTY.

United States Patent OVERHEAD GUARD For: INDUSTRIAL LIFT TRUCK Russell Hastings, Jr., Battle Creek, Harry A. Mackie, Wayne County, and John M. Squier, Battle Creek,

Mich., assignors to Clark Equipment Company, a cor This inventionrelates to overhead guards for the protection of'opera'tors of industrial lift trucks such as are commonly employed for the handling of materials in factories and elsewhere.

These trucks have a tiltable mast structure ahead of the operator station, and forwardly projecting fork frames or other load handling devices are mounted for vertical movement on the mast structure. The truck may be utilized to transport materials held 'by the load engaging devices, and to stack these materials by-elevating the load handling device on the mast structure in order to put one lot of material on top of another.

v In the manipulation of the truck during such a stacking operation, if a load shifts because of careless handling or "because of a'rough floor or for any other reason, material may fall from the load handling device. Such falling material might injure the operator of the industrial lift truck, and various types of overhead guards have been provided heretofore to prevent injury to the operator by falling objects. p

It is the object of the present invention to provide an improved overhead guard structure for an industrial lift truck which is simple and inexpensive, and applicable to trucks of all types.

Considerable inconvenience has been encountered heretofore by lift truck operators and maintenance men whenever it has become necessary to gain access to the power plant of an industrial lift truck which has mounted thereon an overhead guard. Such inconvenience, as well as an excessive consumption of maintenance time, has primarily resulted from the fact that such guards have-gen-- erally been mounted positively on the truck in such a manner that partial or complete disconnection and re moval thereof from the truck has been necessary to facilitate access to the power plant and/ or to permit dis assembly of the counterweight from the truck.

.It is therefore another object of the present invention to provide an overhead guard structure for an industrial lift truck which is so constructed that it is capable of being disconnected from and reconnected to the rear portion of the truck in a minimum amount of time.

It is still another object of this invention to provide an overhead guard structure for an industrial lift truck which embodies a quick disconnect portion capable of self-energization when disconnected from the truck in order to locate said portion out of the vicinity of the adjacent part of the truck.

Other objects and advantages of our invention will be readily apparent to those skilled in the art from the following detailed description.

In carrying out our invention, we provide a generally inverted L-shaped rigid structure connected to a front portion of the truck and extending over the operators head, and generally downwardly depending leg means pivotally mounted on and resiliently connected to the L-shaped portion and connected to a rear portion of the. truck by quick disconnect means.

For a clearer and more complete understanding of our ICC invention reference should be had to the accompanying drawings wherein:

Figure 1 is a perspective view of an industrial lift truck which discloses one manner of employing our invention;

Figure 2 is a side view in elevation of the overhead guard structure shown in Figure 1;

Figure 3 is a 'rear view in elevation of the structure shown in Figure 2;

Figure 4 is a partial plan view of the guard shown in Figure 2;

Figure 5 is an enlarged sectional side view of the means for connecting and disconnecting the pivotable portion of the overhead guard to the rear portion of the truck;

Figure 6 is a side View of the truck of Figure 1 and illustrates one manner of utilizing our invention in order to facilitate ready maintenance of the truck;

- Figure 7 shows a modified form of our invention; and

Figure 8 illustrates a second operative position of the form of our invention which is shown in Figure 7.

Referring now to the drawings, the numeral 10 indicates generally an industrial lift truck. This vehicle includes a body portion indicated generally by the numeral 12 which is mounted on four wheels in the usual manner. In the industrial truck illustrated, the front wheels 14 are drive wheels and are operated by prime mover means, such as an internal combustion engine 15, ,located within the body portion 12 and a hood portion 16. The rear wheels 18 are dirigible wheels and are connected to an operators steering wheel 20 by means of a con ventional linkage for steering the vehicle. The operators station, of which the steering wheel 20 is a part, includes also a seat 22, and a cowl portion 24 mounted at theforward portion of the body 12 and including an operators instrument panel 26. p

At the front end of the body portion of the truck is located a vertically disposed telescopic mast structure indicated generally by the numeral 28. This mast is pivotally mounted at its lower end by trunnion means to the housing of the drive axle to which wheels 14 are connected, and is arranged to be tilted forwardly and rearwardly by'conventional means (not shown). The mast structure 28 includes an outer guide way formed by a pair of channel members 30 and an inner channel construction 32 which telescopes within .the outer guide structure 30, 30.

I A load supporting carriage 34 is arranged to move upwardly and downwardly on the inner construction 32. The load supporting carriage, as illustrated herein, is pro.- vided with a pair of forwardly projecting fork tines 36 which are adapted to engage beneath the load to be transported and raised. Such raising action is produced in a conventional manner by an hydraulic motor 38 comprising an outer cylinder and an inner piston which is arranged to raise and lower the load supporting carriage 34 and the fork tines 36 through a chain and sprocket mechanism. The chains which form a portion of this mechanism are indicated by the numeral 40.

Mounted at the operators station and adjacent to the steering wheel 20 and the cowl section 24 are a plurality of control levers and pedals which enable the operator to variously control the forward and rearward motion of the truck, and the elevation and tilt of the carriage 34 and of the fork tines 36.

The truck 10 also includes at the rear end thereof a counterweight 42 which ordinarily is made of metal and is removably secured to the rear end of the truck to counterbalance loads which are carried on the fork tine at the front of the truck, a

wardly extending hollow rigid members 52 which are parallel to each other and which are secured, as by bolts 54, to opposite sides of the cowl section 24. A pair of transversely extending structure strengthening members 56 extend between the members 52 and a pair of longitudinally extending strengthening members 57 extend between the members 56, all said strengthening members being adapted to support a screen 58 which is suitably connected, as by welding, along the side margins thereof to the members 52 and along the front and rear margins thereof to adjacent members 56. The screen 58 is adapted, of course, to prevent any object which might fall from above from striking the operator.

Secured to each of the rearwardly extending end portions of the members 52 is a bifurcated bracket member 60 to which is pivotally connected by means of pins 62 the upper widened ends 64 of a generally Y-shaped guard portion 66. The leg portion of each bracket member 60 is constructed to register with the opening in each member 52 and is secured in telescoping relation thereto, as best shown in Figure 2. The pivot pins 62 are clevis pins, and are held in position in a well known manner by spring clamps 74. The guard portion 66 includes a pair of diverging tubular members 68 which are suitably secured in telescoping relation at the converging ends thereof to a forked portion 70 of a tubular member 72 and at the diverging ends thereof to a pair of bracket members 64. Adjacent end portions of members 70 and 72 are secured together by means of an annular weld 75 (Figure The member 72 has formed in the center portion thereof an annular groove 76 in which is mounted a ring 78 of rectangular cross-section. The lower end portion of member 72 extends further downwardly on one side thereof than on the other so as to form a downwardly projecting portion 80 which is machined inwardly thereof to form a socket 82, which preferably has the shape of a spherical segment. Secured to the member 72 adjacent the ring 78 is another annular member 84 which provides an abutment for the fixed end of a compression spring 86. Member 72 functions as a guide for spring 86. The opposite and movable end of spring 86 abuts the one end of a cylindrical member 88 which is slidable upwardly along the member 72 from the position shown in Figure 5 The outer peripheral surfaces of annular members 84 and 88 together provide guide means for cylindrical sleeve 90 which encloses the spring 86 and which has inwardly extending lip portions 92' and 94 at opposite ends thereof. The lip portion 92 engages ring 78, as shown in Figure 5, in order to limit the lowermost position of the sleeve relative to member 72, whereas lip portion 94 is engageable with the lower end of member 88 when the sleeve is urged upwardly as by the truck operator, to actuate the member 88 upwardly on member 72 and against the force of spring 86 to a position above the downwardly extending side 80 of member 72.

Whenever sleeve 90 and member 88 are thus moved, the area adjacent downwardly extending portion 80 is no longer bounded by members 88 and 90, and the socket may be engaged with or disengaged from a ball hitch member 96 which is secured to a plate 98. The plate 98 is secured to the upper surface of counterweight 42 as by bolts 100.

Secured to the inner side of each member 52 and extending inwardly thereof is a spring anchor bracket 102 which has an opening therein for the reception of a hooked end of a tension spring 104. The opposite end of each such tension spring is engaged in the groove of an inwardly extending clevis pin 106, which is preferably located substantially in the horizontal plane of 'pivot pin 62 whenever the socket 82 engages the ball hitch 96.

The horizontal plane of brackets 102 is preferably slightly elevated above the plane of pins 62 and 106 thereby causing the axis of spring 104 to be slightly displaced above the axis of pivot pin 62, whereby the springs 104 provide a slight moment force which acts in a clockwise direction about pin 62, as viewed in Figure 2, and which tends to rotate upwardly portion 66 of the overhead guard. When the sleeve is raised against the pressure of spring 86 the socket 82 may be disengaged from the ball hitch 96 by rotating the entire guard portion 66 in a counter-clockwise direction (as viewed in Figure 1). The construction is such that when this action occurs the resultant moment of force of springs 104 about pins 62 increases somewhat; i.e., it increases as a result ofthe increase in length of moment arm between the axes of 'pivot pins 62 and the axes of springs 104 which occurs during such rotation of clevis pins 106 about pins 62. The enlarged end member 64 of each tubular; member 68 is, of course, rotatable within the pockets of'the bifurcated members 60. When the guard portion 66 is thus rotated about pivot pin 62, the resulting moment force of springs 104 is suflicient to maintain said guard portion in a rearwardly extending position and at a relatively small inclination to the plane of the upper leg portions of members 52.

' Figure 6 illustrates the above described operative position of the guard, and clearly shows how the guard is utilized to permit rearward pivoting movement of the hood 16 for ready access tothe power plant 15 and without dismantling the guard 50 from the truck.

To reengage the socket 82 with the ball hitch 96 it is, of course, only necessary to pivot the guard portion 66 downwardly against the force of spring 104 and to lift the sleeve 90 on member 72 so that the ball hitch may enter the socket, whereafter the sleeve 90 is released to permit the spring 86 to actuate said sleeve downwardly to the position shown in the figures, thereby to positively hold the overhead guard portion 66 in the normal locked position thereof.

It will now be apparent that whenever it is desired to remove the counterweight 42 or to service the power plant or steering mechanism adjacent the inner portion of the counterweight, it is simply necessary to actuate the rear portion 66 of the overhead guard upwardly about pivot 62, as above described, and then removethe counterweight or lift the hood, as desired. Thus, the full advantage of protection for the operator is realized by the use of our overhead guard, without the disadvantages heretofore inherent in the use of such guards.

In the modified arrangement which is shown in Figures 7 and 8, like numerals have been applied to parts which are the same as or similar to corresponding parts above described with reference to Figures 1 through 6.

In this second embodiment of our invention, a pair of downwardly depending legs 110 and 112 are independently pivotably and resiliently. connected to opposite ones of the members 52, as above described with reference to Figures 16; these legs have been substituted for the Y- shaped guard portion 66 of the first described embodiment in order to facilitate the mounting, replacement and use of a generally cylindrical tank 113 having a hinged swinging cover plate member 114 for use inindustrial trucks which utilize, for example, liquefied petroleum gas. In this modified arrangement the legs 110 and 112 are separately attachable to and detachable from a pair of laterally spaced ball hitches 96 which are mounted upon the counterweight adjacent opposite sides thereof.

Although only two embodiments of ourinvention have been illustrated and described, it will be apparent to those skilled in the art that various changes in the form and relative arrangement of the parts may be made to suit requirements without departing from' the scope of the invention. V j Y We claim:

1. For use with industrial jlift trucks having a front portion, a rear portion, an upright mast structure located forwardly of the front portion and an operators .Stat on located between said portions, an overhead guard comprising generally inverted L-shaped means secured rigidly to the front portion and extending rearwardly over the operators station, and other means pivotally connected to the rearwardly extending end of said inverted L-shaped means and detachably connected to said rear portion, said detachable connection including ballhitch means mounted on the rear portion and adapted to be alternately and selectively engaged with and disengaged from the said other means, said other means being pivotable about the connections thereof to the inverted L-shaped means when disengaged from said ball-hitch means.

2. For use with industrial lift trucks having a forwardly located cowl section, a rearwardly located counterweight and an operators station located therebetween, an overhead guardcomprising a pair of inverted substantially L-shaped members connected to opposite sides of the cowl section and extending generally upwardly and rearwardly from said connections and over the operators station, pivot means mounted at the rearwardly extending end of each said L-shaped members, Y-shaped means having the diverging ends thereof connected to said pivot means and having a spring loaded sliding sleeve disconnect member mounted adjacent the one end of the common leg of said Y-shaped member, hitching means secured to said counterweight and adapted for engagement by said sleeve disconnect member, and resilient means connecting the pivoted ends of the diverging legs of said Y-shaped member to respective ends of said L-shaped members in such a manner that said Y-shaped member may be maintained in a raised position following disconnection thereof from said hitching means and upward pivoting movement about said pivot means.

3. An overhead guard as claimed in claim 2 wherein said hitching means is a ball-hitch secured to an upper surface of the counterweight substantially on the longitudinal axis of the truck, and said sleeve disconnect member and common leg of said Y-shaped member together provide a pocket adapted to receive the ball hitch therein.

4. An overhead guard as claimed in claim 3 wherein the common leg of the Y-shaped member is of tubular form and said sleeve disconnect member is of similar form and is of such diameter as to provide an elongated annulus between the outer and inner peripheries of the common leg and of the disconnect member, respectively, and spring means surrounding said common leg and located within said annulus for urging the disconnect member in a hitch engaging direction.

5. For use with industrial lift trucks having a forwardly located cowl section, a rearwardly located counterweight, an operators station located therebetween and an upright mast assembly located forwardly of the cowl section, an overhead guard comprising a pair of inverted substantially L-shaped members rigidly connected to opposite sides of the cowl section and extending generally upwardly and rearwardly from said connections over the operators station, pivot meansmounted at the rearwardly extending end of each of said L-shaped members, a normally downwardly depending leg connected at the one end thereof to each of said pivot means and having a spring loaded sliding sleeve disconnect member mounted adjacent the opposite end thereofya hitching means secured to said counterweight adjacent each opposite side thereof and adapted for engagement by a corresponding" one of said sleeve disconnect members, and resilient means connecting the pivoted end of each of said legs to respective ends of said L-shaped members in such a manner that each said downwardly depending legs may be maintained in a raised position following disconnection thereof from the corresponding hitching means and upward pivoting. movement about the respective pivot means.

6. An overhead guard as claimed in claim 5 wherein each said hitching means is a ball-hitch secured to an up per surface of the counterweight adjacent one side of the truck, and each said sleeve disconnect member and corresponding leg together provide a pocket adapted to re ceive the adjacent ball-hitch therein.

7. For use with industrial lift trucks having transversely extending body means located adjacent the forward end of the truck, an upright mast assembly located forwardly of the body means and counterweight means located adjacent the rear end of the truck, an overhead guard comprising a pair of rigid frame members rigidly connected at their one ends to opposite sides of said body means and extending generally upwardly and then rearwardly from the connected ends thereof, means pivotally connected to the rearwardly extending ends of said frame members and detachably secured to said counterweight, said detachable connection between said latter means and the counterweight including hitching means secured to the counterweight and slidable means associated with the said latter means for alternately engaging and disengaging the said latter means from the hitching means, and resilient means connecting the .said latter means to said frame member for urging such latter means upwardly about the pivotal connections thereof with said frame members when such latter means is detached from said counterweight.

8. An overhead guard as claimed in claim 7 wherein said resilient means comprises elongated tension springs means, the axes of which lie substantially in the plane of the pivot connections between the said latter means and the ends of said frame members when the said latter means is attached to the counterweight, whereby said resilient means is substantially ineffective to urge the said latter means in either direction about the pivoted connections thereof when same is attached to said counterweight.

9. An overhead guard as claimed in claim 7 wherein said hitching means comprising a ball-hitch, and said slidable means comprises a sleeve member mounted in radially spaced relation to a portion of the said latter means, and yieldable means mounted between said sleeve member and said latter means for urging said sleeve member toward one end of the said latter means.

References Cited in the file of this patent UNITED STATES PATENTS 2,263,981 Dalecke et al Nov. 25, 1941 2,349,353 Johnson May 23, 1944 2,548,492 Rivard et al Apr. 10, 1951 2,805,887 Selby Sept. 10, 1957 FOREIGN PATENTS 975,118 France Oct. 11, 1950

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