M y 1949- I E. H. PETTLE'R 2,468,999
LIFTING DEvicE Filed 001;. 18, 1946 INVENTOR j Z 3/ BY ATTORNEY Patented May 3, 1949 IIIFTING DEVICE EugeneH-s vRettle1:;,Beazver; Ba;
Application October 18, 1946; SerialiN'o. 7.04; 1,03
This invention relates to" lift trucks ofthe type utilizing: a hoisting fork adapted for manipulation ofthe loa'd 'on the floor'a-nd for stacking or placement purposes.
It' is among the objects of theinvention to provide an improved form oflifting' fork which shall lie-capable of engagingg lifting and stacking or placing loads'=oonsisting-"of a;- plurality of units, such as brick; containersand'--' the like, without any-bottom" supports;
further object of the invention is the provision of* a lifting hoist employinga plurality of gripping devices operable from a; common source, includingmeans-forlocking the gripping elements to the=load by their ownpressure.-
A\ furtiien object of the invention is the provision of a special lifting' device consisting of a pluralityofspaceet for-k members having reinforcing means constituting. pressure abutments which shall be" movably' mounted to facilitate placement. of.- the lifting. device; around? the? load to be handled.
These and other objects. of the. invention will become more'apparent ftom a consideration of the accompanying drawing;.constituting: as part hereon, in whichlike reference; characters. d'esi'gnate likaparts andinwhichi Figs; 1? and 2 aretop plaman'diside elevational views,v respectively, of a lifting; truck; utilizing hoist mechanism embodying the principles of this invention;
Fig. 3 a side elevational view of a hoist;
Fig. 4 a front elevational view thereof, illustrating its position relative to a load to be lifted;
Fig. 5 a top plan view of the hoist; and
Fig. 6 a cross sectional view of one form of a pneumatic type of gripping element.
In the drawing the numeral 1 designates a lift truck of a conventional design used in industrial plants for lifting articles in production lines, the truck being no part of the present invention. In the particular lift trucks to which the invention apper-tains. a hoist in the shape of a elescoping frome member 2 is mounted on the front end of the truck, the particular shape of frame, or whether it be hydraulically or otherwise operated, being of no significance to the present invcntion.
The movable element of the hoist is a frame member 3, Fig. 5, on which are mounted forks 4 that support and lift the load. These forks are usually in the shape of skids or sleds which may be placed under a loading platform on which the articles to be handled are loaded. In accordance with the present invention the forks are not placed beneath the load but around the side of the load and are providedwithside framesii'i of oliannel shape as-shown'in-Fig? 5'.- The forks are adjustable towidth by a splice bar t at; the rear having-- pinholes T for receiving a pin 8 whereby the*-for-kss may bespace'd for'load's of different width withintheli'mits of their' adjustment. A siinil'arbar s, having fiangedends iii, is disposed in the channel of the vertical uprights 5'. It is likewise a splice bar, as shown, having pin holes M for receiving the-anchorbolt' 12 sothat the front-bar 9' canbe adjusted tothe same width asthe-rear bar As shown in Figs. 3' and 4; the bar 9' is suspended by cables l3 extending over guide wheels M that are-Wound by'a= shaft lithat' ispreferably motor driven, there being two suspension cablesas shown in Fig: 4 to-ba1ance therod 9 in. it's-vertical sliding movement inchannels 5-.
The fork element's fiareprovidedwith hydraulic jacks l6 connected to-a' source of pressure fluid at. I]; Figs; 3. and 4; there being four sets of jackssliown, although any desired number may heutili'zeddepending upon the character of the load t'oibe handled.
The forks-:4 are preferably I-' beams in which the jacks I6? are. mounted, and in theform of grippingsdeviceeshown imEig; 6 an inflatable tube I8 is employed in place=of-"tlie jacks- IS,- the tube running: the: full length ofit-h'e 1- beams and being connected to the pressure fluid source I! to exert a gripping action on the load when inflated, such tube being protected by the flanges of the I beam.
In the drawing, brick l9, such as fire clay brick, is illustrated as the load to be handled, there being four rows of brick seven brick high, as shown in Figs. 4 and 5. The improved form of lifting hoist may also be employed for handling boxes in food factories or in industrial plants where the product is packaged for shipment.
The operation of the above described lifting hoist is briefly as follows. The locking bar 9, Figs. 3 and 4, is raised from the position shown in Fig. 3 where it is in substantial register with the longitudinal axis of the forked members 4 o to the upper limit of its travel which is at the top of the channels 5, the winch or motor driven shaft l5 being actuated for that purpose. When it has reached the upper limit of its travel in the channel frames 5, the forks 4 and side frames 5 are separated by a space which may be termed the loading space that has been previously determined by adjustment of the locking bar 9 and the rear bar 6 to suit the width of the load to be handled.
In case of the brick l9, as shown in the drawings, the fork arms 4 have been adjusted to embrace rows of brick with sufficient clearance to clear the jacks 16 when the lifting truck is maneuvered to the position of the pile. The truck is advanced to the position where the forks l have been aligned with the stacked brick, as shown in Fig. 5, with the jacks IS in substantial center of each transverse row of brick. When in this position the winch shaft [5 is operated in the reverse direction to lower the locking bar 9 to the position shown in Fig. 3, and pressure fluid through the source connection IT is then applied to the hydraulic jacks l6 which exert the necessary gripping pressure against the faces of the bottom row of the brick as shown in Fig. 4. The gripping pressure of the hydraulic jacks l6 reacts against the heads ID of the tie bar 9 so that the I beam shaped forks 4 are rigidly secured against lateral displacement which would otherwise result from the pressure of the hydraulic jacks abutting against the faces of the brick.
When so engaged the load of brick is rigidly held and adapted to be lifted as shown in Fig. 4 to any desired height within the limits of travel of the telescoping frames 2. The truck then transports the load to wherever it is desired, such as a truck bed for hauling or a stock pile for stacking. When the load has been brought to rest to its new position, the hydraulic pressure of the jacks I6 is released and the front tie bar 9 is again raised by the winch shaft I6 to its upper position to clear the top of the load of brick, in which position the hoist truck is free to back away, leaving the load in place.
Where a flexible tube, such as the member l8 of Fig. 6 is employed in place of the jacks I6, the application of pressure fluid eifects a firm gripping action of the forks with the load to be hoisted because the flexible tube l8 will lay itself on any surface with which it comes in contact.
The gripping fork type of hoist, as herein disclosed, may obviously be usefully employed in handling rectangular containers, such as boxes or packages containing food products or the like, and may be utilized for lifting any objects having parallel fiat faces, either as single units when of a large size, and in multiple units as in the case of the bricks herein illustrated.
Although one embodiment of the invention has 4 been herein illustrated and described, it will be evident to those skilled in the art that various modifications may be made in the details of construction without departing from the principles herein set forth.
1. In a lifting hoist, a pair of gripping forks comprising a plurality of substantially rectangular frames in parallel alignment, the front uprights of which are channel members for receiving a tie rod that is slidable vertically therein, a tie rod disposed in said channels, the ends of which are adapted to interact vnth said channel to prevent displacement of the tie bar therein, means for raising and lowering said tie bar, and means mounted on the lower horizontal frames of said forks for exerting a gripping pressure on a load disposed between said forks whereby the load is supported on said forks from pressure exerted on the side of the load.
2. A lifting device for truck hoists comprising a pair of I beams having an adjustable spacer bar at the rear thereof to vary the space between the I beams, gripping elements mounted on the inner channels of the I beams, a channel joined to the ends of said I beams and extending vertically a distance in excess of the height of the load to be hoisted, a tie bar movably mounted in said channel members, hoist mechanism for raising and lowering said tie bar to clear the load when the I beams are brought into parallel alignment with the side faces of the load and to secure the I beams against lateral displacement when the gripping means are actuated, and means for energizing said load gripping means to simultaneously subject them to gripping force when brought into engagement with the load.
EUGENE H. PETTLER.
REFERENCES CITED The following references are of record in the file oi this patent:
UNITED STATES PATENTS Number Name Date 2,213,629 Fontaine Sept. 3, 1940 2,308,648 De Vry et al Jan. 19, 1943 2,323,810 Fontaine July 6, 1943 2,403,356 Francis July 2, 1946