US2554140A - Hoisting apparatus - Google Patents

Description

May 22, 1951 L. EAKIN HOISTING APPARATUS 3 Sheets--SheefI l Filed Dec. 19, 1947 uer: 10i/1,7201. Elin May 22, 1951 L.. L. EAKIN HoIsTING APPARATUS Filed Deo. 19. 1947 5 Sheets-Sheet 2 May 22, 1951 L. L. EAKIN HoIsTING APPARATUS 3 Sheets-Sheetl 3 Filed Dec. 19. 1947 apup:

lanzada/1w By i ' ,//HWJ/qy` Patented May 22, 1951 UNITED STATES PATENT OFFICE HOISTING APrARA'rI-Js Lourie L Ea'kin, Ventura, Calif. Application December 19, 1947, lserial No. 792,792

8 Claimsl My invention relates to hoisting apparatus, and particularly to an apparatus which is especially suitable for installation on a transporting vehicle, such as a motor truck, land having means for hoisting relatively heavy objects and placing them on removing them from the platform of the truck. The present invention ris ,concerned with a hoisting apparatus of the lgeneral type disclosed in my pending application for patent on vehicle hoisting apparatus, Serial No. 746,248, filed May 6, 1947. The present application embodies novel and improved actuating means for pivoting the hoist forwardly and rearwardly.

One object of my invention is .to provide a hoisting apparatus which includes a boom pivoted on an axis transversely of its platform adjacent one end thereof to adapt it to pivot to an extended position projecting rearwardly from the platform to receive a load which is attached to the end of a ,cable carried by the boom, and to a retracted position toward .the forward end of the platform so that it may be lowered onto the platform. The invention kfurther provides a novel power-actuated means for pivoting the hoisting boom to its different angular positions.

It is -`desirable in hoisting apparatus of this general type that the hoisting boom be adapted to ypivot `througl'i lsubstantially 180 degrees, that is, from a horizontal position extending forwardly from its pivot to a horizontal position projecting rearwardly v.from the truck, or other vehicle on which the apparatus kmight be installed, so that the end of the boom may be lowered to a point close to the ground, Vor to the lObject which is to be raised. Itis preferable that hydraulic power means be employed for pivoting the `looom in order to obtain the power necessary to .pivot the boom when `relatively heavy .objects are being lifted. In such apparatus, it is the nsual practice to operatively connect the piston of a hydraulic actuating jack to a relatively short arm projecting from the pivot of the boom in a downward direction. Since the boom moves through substantially 180 degrees the arm liiewise swings through the same angle, land at the extreme vforward and rearward movement .of the arm the armand piston approach alignment, and this has lthe effect to cause a substantially deadcenter condition. Due to this condition, tremendous amount of vpower is required to obtain the mechanical advantage necessary to overcome the weight ofthe Vboom and its supported load.

It is a further object of this invention to pro-- vide means for augmenting the power yproduced by the usual hydraulic jack at the start of the upward pivoted movement of the boom, so that adequate power is provided for overcoming inertia of the boom and initiating its upward tilting movement. This object can be best accomplished by the provision of auxiliary or secondary fluid-actuated jacks which are operatively connected to the pivotal end of the boom only when the latter is at the forward and rearward extremities of its pivotal movement, these jacks thus functioning to assist the main hydraulic jack in overcoming inertia of the lifting boom. After the boom has been tilted upwardly to a position wherein a greatly improved mechanical advantage exists., sufficient power is derived from the main hydraulic jack to .complete the piv` .v otal movement of the boom, and at this lpoint the operation of the auxiliary vjacks :is arrested. By providing a pair of the auxiliary fluidactuated jacks and locating one forwardly and one rearwardly of the pivot of the boom, they may be ,selectively voperated to assist in initially tilting the boom upwardly from both forward and rearward positions, and this is an important Qbject yof my invention.

is kanother object` of the invention t0 Drovide means for .cushioning the load when lower.- ing the boom, and, in this respect, I make use of .the auxiliary fluid-actuated pistons which limit ,the downward tilting movement of the boom and which maybe actuated in a manner to positively `control the iinal .downward swinging movement, to ease Ithe boom slowly and safely down,- wardly leven when large loads are sustained thereby.

Another object is to provide, in a hoisting apparatus .of the character referred to, a hoisting boom of novel construction, capable `of sustaining great loads, and one which, when in its forward linoperative position, will not interfere with objects located on the truck platform Vor other parts of the vehicle.V Preferably, the `boom is of angular shape so that its distal end isadapted to either Yoverlie the ca b of the truck', in close Proximity thereto, ,or to be disposed Closely advjacent the ,rear side .of the cab when the boom is in Kits vforward inoperative position, thus avoid- .ing the possibility Yof the `boom projecting above the truck to a height where it might interferev with the driving of the vehicle and v,where it might strike trees, wires, bridges, and other overhead objects- ,Further objects of ithe invention are set forth .in ,the ,fellowing specification which describes several preferred embodiments thereof, by way of example, as illustrated by the accompanying drawings. In the drawings:

Fig. 1 is a side elevational view of a motor truck equipped with one form of hoisting apparatus, in accordance with my invention;

Fig. 2 is a plan view of the rearward end of the truck, with the platform thereof removed to disclose the fluid-actuated means for operating the hoisting boom;

Fig. 3 is a longitudinal sectional view, taken substantially on line 3 3 of Fig. 2, and showing the relationship of the parts of the actuating means when the boom is in its forward retracted position;

Fig. 4 is a view similar to Fig. 3, but illustrating the relationship of the parts when the boom is in its rearmost, extended position; and,

Fig. 5 is a diagram of the hydraulic circuit for the several lifting jacks.

Referring to the drawings in detail, my improved hoisting apparatus is shown, by way of example,v as installed on a conventional motor truck IIJ, which is provided with a platform for supporting various objects during transportation, and a drivers cab I2 mounted on the chassis I3. Fixed to the side rails |4 of the chassis I3 are tubular bearings l5 which are adapted to receive a tubular axle or pivot member i6 to adapt the latter to rotate on an axis extending transversely of the truck, beneath its platform II. Welded or otherwise secured to the ends of the tubular axle I6 are the ends of the arms I9 of a hoisting boom 26. The arms |9 extend parallel to the lateral edges of the platform I At a suitable distance forwardly of the axle |6 they are inclined upwardly and inwardly, and then extend substantially horizontally so that their convergent ends meet. Through this construction the distal end of the boom is disposed above the cab I2 of the truck in relatively close relation thereto, to provide compactness and prevent the end from projecting upwardly to an extent where it might strike overhead wires, trees, and the like. At the point of joinder of the arms I9, a V-shaped element is secured, this element being adapted to rotatably support a grooved pulley or sheath 23. A cable 24 passes over the sheath 23 and has a hook 25 at one end. The other end of the cable 24 is wound around the drum 26 of a power winch, indicated at 21, such means not being herein shown in detailas they may be of any suitable type generally employed in hoisting equipment.

A second pulley or sheath 2| is rotatably mounted between the arms I9 of the boom at a point substantially midway between their ends, and the cable 24 may extend around this pulley instead of the pulley 23, if desired, as indicated by the heavy dot-and-dash lines in Fig. 1, so that the effective length of the boom is decreased. This is advantageous when lifting certain kinds of objects.

The hoisting boom is adapted to be pivoted to any of the positions indicated in Figi. 1 by means of fluid-actuated devices, to be next described. The pivot tube or axle |6 has a pair of spaced radial arms 3l) Welded thereto between which is connected the end of a piston rod 3| of a main hydraulic jack 32, the rod 3| being pivotally connected to the arms 36 by a pin 33. The rod 3| carries a piston 34 at its forward end, the piston being slidable in a hydraulic cylinder 35 which is pivotally connected to a bracket 36 carried by a cross-member 31 of the vehicle chassis I3. The end of the cylinder 35 is connected by hydraulic lines 64 and 5I which lead to a manually-operable valve 38 (Fig. 5), which may be actuated to selectively introduce fluid under pressure into either end of the cylinder to actuate its piston 34 which acts through its rod 3| and the arms 30 to turn the pivot tube or axle I6 in either direction to swing the boom 26 between its two extents of movement, illustrated by full lines and dot-and-dash lines in Fig. 1. While the main hydraulic jack 32 functions to move the boom 2|! through the major portion of its pivotal movement, the movement of the boom at the extreme forward and rearward ends of its movement is controlled by auxiliary fluid-actuated means, to be presently described.

It Will be observed by reference to Figs. 3 and 4 that, when the boom is at th-e extent of its for- Ward and rearward movement, the arms 3U extend nearly horizontal, and an almost deadcenter relation exists between the arms 36 and the piston rod 3|. Because of this very unfavorable leverage condition, and due to the fact that the great inertia caused by the heavy boom and the weight supported thereby must be overcome, torque of great magnitude must be applied to the axle I6, and, since the moment arm 36 is relatively short, it is apparent that tremendous power is required to produce such force. For this reason it is very desirable, and quite essential, that the main hydraulic-actuating means be assisted during the start of the pivotal movement of the boom upwardly from its extended and retracted horizontal positions. In the present invention this assisting means consists of auxiliary or secondary fluid-actuated means to be next described.

Pivotally connected to a pin 39 held in a bracket 40 carried by a cross-strut 4| of the frame I3 is one end of a rst auxiliary hydraulic cylinder 42 in which a piston 43 is slidable. The piston 43 has a rod 44 which extends rearwardly and is connected to a pin 45 carried between the ends of a pair of arms 46, which are pivoted on a short shaft 41 pivotally mounted in a pair of brackets 4B welded to a cross-member 49 of the frame I3 (Fig. 2). The pin 33l has its ends projecting from the sides of the arms 3D, and a finger 56 on the pivot shaft 41 is adapted to engage one of the projecting ends in the manner to be later explained. The cylinder 42 is of the single acting type and, as shown in Fig. 5, has only one end connected by a single line 5|a to the selector valve 38. When hydraulic fluid is introduced into the cylinder 42, the piston 43 is moved rearwardly, and thus the arm 46 and the nger 56 are pivoted from the position shown by full lines to the position indicated by dash-lines in Fig. 3, and, conversely, when the fluid is permitted to escape from the cylinder, the arm and finger move from the dash-line position to the full line position.

'Ihe boom-actuating means also includes a second auxiliary cylinder 55 which is pivoted on a pin 56 carried by a bracket 51 welded to the crossmember 49 (Fig. 2). Slidable in the cylinder 55 is a piston 58 which has a rod 59 extending forwardly and pivotally connected to a pin 66 carried between a pair of arms 6| mounted on a shaft 62 carried by the bracket 4|). A finger 63 is rotatable With the shaft 62 and adapted to engage the other projecting end of the pin 33. When the pison 58 is slid forwardly, the arm 6| and nger 63 are pivoted from the position indicated by double dot-dash line'to that shownl by full lines in Fig. 3, and, conversely, when the piston is slid rearwardly the arm and nger are returned to the first mentioned position. The cylinder 55 is also of the single acting type, having a single port connected by a line 64a to the selector valve 38 (Fig. 5).

The hydraulic system shown in Fig. includes, in addition to the elements already described, a reservoir 35, a pump 55, a by-pass valve 61, and a pressure-responsive valve 68, connected in the circuit as shown.

Assuming that the boom 2|) is in the position shown by full lines in Figs. l, 2, and 3, with the parts of the actuating mechanism assumingthe relationship shown in Fig. 3, the boom may be pivoted to the rearward extended position indicated by dot-and-dash lines in Fig. l, and full lines in Fig. 4, in the manner next explained. By operating the selector valve 38, hydraulic uid under pressure is caused to be introduced into the right-hand or near end of the main cylinder 35 through the line 5| so that the piston rod 3| tends to pivot the arms 3G and boom 20 in clockwise direction. However, due to the fact that at this time an almost dead-center relation exists between the arms 33 and the piston rod 3|, and because of the fact that the great inertia caused by the heavy boom, and any object supported thereby, must be overcome, torque of great magnitude must be applied to the axle I5. Since the moment arm 30 is relatively short, tremendous power is required to produce the initial force. In accordance with the present invention, the'main hydraulic-actuating means is assisted during the start of the upward pivotal movement of the boom. To effect such assistance, hydraulic uid is introduced into the auxiliary cylinder 42 so that its piston rod 44, acting through the varm 46 and shaft 47|, functions to pivot the arm and finger 50 from the position shown by full lines to the position indicated by dash lines in Fig. y3. Inn this manner, the nger 50 acts against the pin 33 and thus assists the piston rod 3| in swingingthe arm 35 in clockwise direction to move the boom to the position indicated by dash lines in Fig. 3. The movement of the finger 5U is limited, however, by the extent of sliding movement of the piston rod 44 so that it can move only to the position indicated by dash lines in Fig. 3. However, due to the fact that the -boom 20 is now approaching a vertical position, less effort or force is required to move the same, and this force is readily applied by the main cylinder 35 which now acts independently.

During the continued rearward pivotal movement, the boom 20 passes across an imaginary vertical center line drawn through the axle l5. At this juncture, force applied by the main cylinder 35 is augmented by a gravitational force, and, unless these forces are checked, the boom would rapidly and violently descend. The valve 53 is employed for the purpose of controlling such downward pivotal movement of the boom. the valve being operative, in response to a sudden increase in pressure to decelerate the rate of sliding movement of the piston rod 3|, so as to control the descent of the boom.

When the boom 20 arrives at the position indicated by dot-and-dash lines in Fig. 3, the pin 33 carried by the arm 30 engages against the iinger 63 which is, at this time, held in the position shown by dotted lines in Fig. 3 by reason of the piston rod 58 being in extended position. At this point the selector valve 38 is manipulated to permit fluid to bleed from-the cylinder 55, so that the nger 63 and arm 6| move to the position indicated by double dotdash lines in Fig. 3 to permit the boom 20 to descend to its fully extended position, as represented by double dot-dash lines in Fig. 3 and dotand-dash lines in Fig. l. The boom 20 is then in position to deposit an object 'IU supported thereby at a considerable distance from the rear end of the truck Hl, and the object can be lowered by operating the Winch 21. It is thus seen that the present boom-operating means maintains positive control over the boom at all times, and by operating the selector valve 38 the boom may be stopped at any desired angle.

To pivot the boom 20 from the fully extended to the fully retracted positions represented by the respective dot-and-dash and full lines in Fig. 1, the operation explained above is reversed. That is to say, the main cylinder or jack 32l and the auxiliary jack cylinder 55 are simultaneously energized so that the iinger 53 functions to depress the pin 33 and thus move the boom 20 upwardly from the position indicated by full lines to that represented by dot-and-dash lines in Fig. 4, at which time the auxiliary cylinder 55 becomes inactive due to the fact that its piston rod 59 is fully extended. From this point on the main cylinder 32 operates alone to swing the boom 2|) forwardly until the latter reaches the position shown by dash lines in Fig. 4, the valve 58 functioning to control such movement as the boom passes a vertical position.

Upon reaching the dash-line position in Fig. 4, the pin 33 engages the finger 50 of the arm 46, which is maintained in the position shown by full lines in Fig. 4 by the fully extended piston rod 43. To lower the boom 20 to the position shown by double dot-dash lines in Fig. 4, the piston rod di is retracted into the auxiliary cylinder l2 so that the finger 5i! is pivoted to the position indicated by double dot-dash lines in Fig. It will be understood that by manipulating the valve 33 the boom 25 can be brought to rest at any point intermediate its extended and retracted positions, such as the position indicated by the dash lines in Fig. l, so that the object 'l0 can be lowered onto the truck platform at any desired location While the object Hl herein shown is one which may be set upon the platform, it will be apparent that the boom 25 is capable of lifting and supporting other objects, such as poles, in upright position, to permit them to be erected in holes in the ground. The hoisting apparatus may thus be said to be universal in its application to use, and may be advantageously employed on transportation and con-struction vehicles. Moreover, the hoisting equipment may be readily applied to existing trucks with minimum change in their structures.

While I have herein shown and described the improved hoisting apparatus, as embodied in a preferred form of construction and applied to use with a particular type of vehicle, by way of example, it will be apparent that the construction of the apparatus and its application to use may be varied in certain respects, in association with a vehicle, or other means or mechanisms, without departing from the spirit or scope of the invention. Therefore, without limiting myself in this respect, I claim:

l. In an apparatus of the class described, comprising: a support; a boom pivoted transversely a pivot pin; primary actuating means connected to said pin and operable to pivot said arm and said boom through the major portion of their movement in either direction; a pair of fingers movable forwardly and rearwardly of the pivot of Said boom and adapted to engage and move said pivot pin lwhen moved so as to pivot said boom; and a pair of secondary actuating means pivoted on said support forwardly and rearwardly of the pivot of said boom and operatively connected to said fingers so as to pivot the same during the initial actuation of said primary actuating means so as to assist said primary actuating means in raising said boom.

2. In an apparatus of the class described, comprising: a support; a boom pivoted transversely of the support to adapt it to pivot to a forward position overlying the support, to a rearward position projecting rearwardly from the support, and to position intermediate said forward and rearward positions said boom having an arm projecting from its pivotal end and provided with a pivot pin; primary fluid-actuating means connected to said pin and operable to pivot said arm and said boom through the major portion of their movement in either direction; and a pair of secondary fluid-actuating means pivoted on said support forwardly and rearwardly of the pvot of said boom and adapted to engage and move said pivot pin during the initial actuation of said primary actuating means so as to assist said primary actuating means in raising said boom.

3. In an apparatus of the class described, comprising: a support; a boom pivoted transversely of the support to adapt it to pivot to `a forward position overlying the support, to a rearward position projecting rearwardly from the support, and to positions intermediate said forward and rearward positions, said boom having an arm projecting from its pivotal end and provided with a pivot pin; primary fiuid-actuating means connected to said pin and operable to pivot said arm and said boom through the major portion of their movement in either direction; a pair of fingers movable forwardly and rearwardly of the pivot of said boom and adapted to engage and move said pivot pin when moved so as to pivot said boom; and a pair of secondary uid-actuating means pivoted on said support forwardly and rearwardly of the pivot of said boom and operatively connected to said fingers so as to pivot the same during the initial actuation of said primary actuating means so as to assist said primary actuating means in raising said boom.

4. In an apparatus of the class described, comprising: a support; a boom pivoted transversely of the support to adapt it to pivot to a forward position overlying the support, to a rearward position projecting rearwardly from the support, and to positions intermediate said forward and rearward positions, Asaid boom having an arm projecting from its pivotal end and provided with a pivot pin; primary actuating means connected to said pin and operable to pivot said arm and said boom through the major portion of their movement in either direction; a pair of fingers pivotally mounted forwardly and rearwardly of the pivot of said boom and adapted to engage and move said pivot pin, upon pivotal movement, so as to pivot said boom; and a pair of secondary actuating means pivoted on said support forwardly and rearwardly of the pivot of said boom and operatively connected, respectively, to said fingers pivoted rearwardly and forwardly of said pivot of said boom so as to pivot the finger during the initial actuation of said primary actuating means so as to assist said primary actuating means in raising said boom.

5. In an apparatus of the class described, comprising: a support; a boom pivoted transversely of the support to adapt it to pivot to a forward position overlying the support, to a rearward position projecting rearwardly from the support, and to positions intermediate said forward and rearward positions, said boom having an arm projecting from its pivotal end and provided with a pivot pin; primary actuating means connected to said pin and operable to pivot said arm and said boom through the major portion of their movement in either direction; shafts pivoted forwardly and rearwardly of the pivot of said boom; fingers carried by each of said shafts and adapted to engage and move said pivot pin, upon pivotal movement of each of said shafts, so as to pivot said boom; secondary actuating means pivoted on said support; and arms carried by said shafts and connected to said secondary actuating means so that said shaft and said fingers` are pivoted during the initial actuation of said primary actuating means to assist said primary actuating means in raising said boom.

6. A hoisting means as dened in claim 2, and including: a fluid system for said fluid-actuating means, said system having pressure-inducing means, selector valve means, for controlling the introduction into and discharge of fluid from each of said actuating means, and pressure-responsive valve means automatically operative, when said boom passes a vertical position during its pivotal movement in a forward or rearward direction, to control the rate of flow of fluid into and from said primary actuating means so as to prevent a rate of pivotal movement of said boom in excess of a predetermined rate.

' 7. In an apparatus of the class described, having: a support; a boom pivoted transversely of the support to adapt it to pivot to a forward position overlying the support, to a rearward position projecting rearwardly from the support, and to positions intermediate said forward and rearward positions, said boom having an arm projecting from its pivotal end and provided with a pivotpin; a primary fluid-actuated cylinder pivotally mounted forwardly of the pivot of said boom and connected to said pin so as to pivot said arm and said boom through the major portion of their movement in either direction; a pair of secondary fluid-actuated cylinders pivoted forwardly and rearwardly of said boom pivot and adapted to engage and move said pivot pin during the initial actuation of said primary actuating cylinder so as to assist said primary actuating cylinder in raisng said boom: a fluid system for all of said actuating cylinders; and valve means in said system for controlling the actuation of all of said actuating cylinders in a manner such that simultaneous actuation of said primary actuating cylinder and either of said secondary actuating cylinders is effected.

8. In an apparatus of the class described, comprising: a support; a boom pivoted transversely of the support to adapt it to pivot to a forward position overlying the support, to a rearward 9 position projecting rearwardly from the support, and to positions intermediate said forward and rearward positions, said boom having Aan arm projecting from its pivotal end and provided with a pivot pin; primary actuating means connected 5 to said pin and operable to pivot said arm and said boom through the major portion of their movement in either direction; and a secondary actuating means spaced from the pivot of said koom 4and pivoted on said support, said secondary actuating means being adapted to engage and move fsaid pivot pin during initial actuation of said primary actuating means so as to assist said primary actuating means in raising said boom.

LOURIE L. EAKIN.

10 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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