US2581087A - Hoisting apparatus - Google Patents

Description

L. L. EAKIN Jan. I, 1952 HOISTING APPARATUS 3 Sheets-Sheet 1 Filed Dec. 22,' 1947 Jan. 1952 L. EAKIN HOISTING APPARATUS 5 Sheets-Sheet 2 L--- willl h n ELIIFIN LE Filed Dec. 2,2, 194'? Jan. 1, 1952 1.. 1.. EAKIN HOISTING APPARATUS 5 Sheets-Sheet 5 Filed Dec. 22, 1947 ielz'alflju Patented Jan. 1, 1952 UNITED STATES PATENT OFFICE 2,581,087 HOISTIN G APPARATUS Lourie L. Eakin, Ventura, Calif. Application December 22, 1947, Serial No. 793,163

11 Claims.

My invention relates to hoisting apparatus for use in hoisting and moving relatively heavy objects from one location to another. The pres ent invention is concerned with a hoisting apparatus which is embodied in a self-contained unit adapted to be mounted on the platform of a truck, railroad flat-car, the deck of a boat, or any stationary platform upon which objects are to be placed, or from which the objects are to be removed. As a practical application of my invention, the hoisting apparatus may be employed on a transporting vehicle in a manner similar to that disclosed in my pending application for patent on Vehicle Hoisting Apparatus, Serial No. 746,248, filed May 6, 1947.. Specifically, the present invention pertains to a novel and improved power-operated means for actuating the hoisting boom. Y a It is desirable in hoisting apparatus that the hoisting boom be capable of pivoting through an angle of substantially 180 degrees, that is, from one horizontal position to the opposite horizontal position, so that the end of the boom can be lowered to a point close to the ground, or to the object which is to be raised. It is preferable that hydraulic power means be employed for pivoting the boom in order to obtain the power necessary to pivot the boom when relatively heavy objects are being lifted. In such apparatus, it is the usual 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 likewise swings through the same angle, and at the extreme forward and rearward movement of the arm the arm and piston approach alignment, and this has the eiTect to cause a substantially dead- .centerj condition. Due to this condition, a tremendous amount of power is required to obtain the mechanical advantage necessary-to overcome the weight of the boom and its supported load.

' It is an object of this invention to provide "means, actuated by the hydraulic ram at the start of the lifting operation, for increasing the force applied against the boom so as to overcome such a substantially dead-center condition and initially pivot the boom to a position wherein the piston of the hydraulic ram can complete the pivoting of the boom. This object can best be attained by so mounting the actuating ..ram, or hydraulic cylinder, that it is movable, within prescribed limits, toward and away from the boom pivot, such movement of the cylinder being utilized to actuate a cam lever which, in

' means for operating the turn, is operative to initially swing the boom through a predetermined angle, the piston rod of the hydraulic jack then becoming active to complete the pivotal movement of the boom to its maximum extent. By this construction, a single hydraulic jack can be employed for pivoting the boom from one substantially horizontal position to the opposite horizontal position without the aid of auxiliary jacks, or other power means.

Another object is to provide a power-actuated hoisting apparatus in which the boom is pivoted through substantially 90 degrees to an upright in a manner such that the object can be lowered object is best accomplished by providing valve means for regulating the bleeding of the hydraulic fluid from the hydraulic jack which, at this time, serves to control such action of the boom in a manner to positively control the final downward pivotal movement, to ease the boom slowly and safely downward even when large loads are sustained by the boom.

' Another object is to provide a hoisting apparatus of sturdy construction which is embodied in a'self-contained unit capable of being mounted on either a stationary support, such as a freight vehicle. It is within the concept of my inven tion to mount the apparatus on a turntable so that it is capable of lifting objects at one location and deposiing the objects at various other positions.

Further objects of the invention are set forth in the following description and will be apparent from the drawings, which are intended for the purpose of illustration only, and in which:

Fig. l is a side elevational view of my improved hoisting apparatus; 7

Fig. 2 is a plan view hoisting boom;

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

Fig. 4 is a view similar to Fig. 3, but showing the relationship of the parts during the initial pivotal movement of the boom; and,

Fig. 5 is a diagram of the hydraulic circuit for the power-operated mea Referring to the drawings in detail, my imof the power-actuated ating means is similar means is provided viouslyexplained, is slidable in the to be engaged by the inclined edge proved hoisting apparatus is shown as mounted on a stationary platform Iii, by way of example, but it will be understood that the apparatus can be installed on a truck, or other vehicle. The apparatus includes a rectangular base Ii having side rails I2 joined at their ends by end members I3 and I5. Fixed to the side rails I2 of the base I l are tubular bearings i5 in which a tubular axle or pivot member I 3 is adapted to rotate. Welded or otherwise secured to the ends of the tubular axle [5 are the ends of the arms is of a hoisting boom 28, the arms extending parallel to the side rails I2, as shown in Fig. 2. The boom 25 may be of the same general form as disclosed in my pending application, referred to previously, and thus is not described in detail herein. Sufiee it to say that the arms I9 converge at their distal ends, and rotatable at this end of the boom is a.

pulley or sheath 23 over-which a cable 22 passes, the cable having a hook 25 at one end. The other end of the cable is wound around the drum 26 of a power winch, indicated at 21.

The hoisting boom is adapted to be pivoted to any of the positions indicated in Fig. 1 by means of a hydraulically-actuated mechanism to be next described. The pivot tube or axle It has av pair of spaced radial arms 30 (Fig. 2) welded thereto, between which is pivotally connected the end of a piston rod 3| of a hydraulic jack 32 by means of a pin 33. 34 which is slidable in the cylinder 35 of the jack 32. The cylinder 35 has ears 35 at its end between which extends a pivot pin 31, the pin projecting through horizontal slots 38 in spaced I3. It 'is. thus seen that the hydraulic cylinder 35 may brackets 39 carried by the end member move longitudinally to an extent limited by the slots 38, and the cylinder is also capable of pivoting on the pin 31.

With the exception of the slidable pivot means, described above, the fluid-actuated boom operto conventional hydraulic mechanisms for pivoting booms, and similar arms. As previously pointed out, it is desirable that the boom be capable of being. pivoted through substantially 180 degrees, but such movement of the boom cannot be readily attained by the use of. such conventional operating. mechanism for the reason that the hydraulic piston rod and the arms 36 of the boom approach a straight line, or dead-centerrelationship, at the opposite extremes of pivotal movement of the boom. Consequently, unless some auxiliary for effecting the initial pivotal movement of the boom, it is impossible for the hydraulic jack to tilt the boom through such an arc. The present invention contemplates means for initially starting the pivotal movement of the boom, such means being constructed and arranged as next described.

Pivoted on a pin AI extending between bracket arms 42 carriedby the end member Id of the base I I is an arm 43. The end of the arm d3 carries a pin 44 on which is pivotally connected one end of a relatively long link 55, the other end of the link being pivotally joined to the pin 31 which, as preslots 38. Carried by tthe pin M is a cam arm t5 having a cam edge 41 which, when the boom is in the inoperative position, ing end of the pin 35 on the arms 35.

Freely pivoted on the pin 31 is a stop ele ment 59 which is provided with a cylindrical follower 5I at one side. The follower 5I is adapted 53 of a slide The rod 3I carries a piston shown in Fig. 3, overlies the projectof the cylinder from the full line to member 56, which is slidable in a guide bracket 55 carried by the end member I3 of the base II. The slide member 54 is adapted to be slid by means of a link or push-bar 58 to which it is connected by a pivot pin 51. The other end of the push-bar is pivotally connected to one of the arms 33 by means of a pin 58.

The hydraulic cylinder 35 is connected in a hydraulic system in the manner indicated in the diagram, lines 60 and BI, extending from the opposite ends of the cylinder to a selector valve 62. The system also includes a reservoir 33, a pump 64, a by-pass valve 55, and a pressureresponsive valve 66.

Assuming that the boom 26 is in the position shown by full lines in Figs. 1 and 3, with the parts of the actuating mechanism assuming the relationship shown in Fig. 3, the boom may be pivoted to the position indicated by dash lines in the manner next explained. By operating the selector valve 52, hydraulic fluid under pressure is caused to be introduced through the line GI into. the right-hand end of the cylinder 35. Since the boom is in lowermost position and offers maximum resistance to sliding movement of the piston 34, the fluid, acting against the righthand end of the cylinder 35, causes the latter to move toward the right with its pin 31 riding in the horizontal slots 38.

During movement of the cylinder 35 in this manner, the link G5 is also shifted toward the right, and, since it is connected to the cam arm 43, 55 by the pin 45, the cam arm is caused to pivot in counterclockwise direction, as viewed in Fig. 4. Consequently, the cam edge 41 acts against the pin 33 to pivot the arms 3 in clockwise direction and thus cause the boom to pivot upwardly. The extent to which the cam edge 41 is capable of pivoting the arms and boom 25 is illustarted in Fig. 4. It is thus seen that when fluid is first introduced into the righthand end of the cylinder 35, the boom 20 is initially pivoted from the position shown in Fig. 3 to that illustrated in Fig. 4.

During pivotal movement of the arms 30 to the position shown in Fig. 4, the push-bar 56 acts to slide the slide member 54 toward the left. Simultaneous with the. sliding movement of the slide member toward the left, the stop element 58 is carried toward the right by reason of its connection with the pin 31, so that its follower 51 engages the inclined edge 53 of the slide member 54, Movement of the stop member and slide member therefore results in pivotal movement of the stop member from the position shown in Fig. 3 to that illustrated in. Fig. 4, so that the end of the stop member is disposed adjacent the end member I3 of the base II.

When the cylinder reaches the position shown in Fig. 4, its movement toward, the. right is arrested by reason of the engagement of the pin 31 with the right-hand end of the slots 38. It is apparent, therefore, that further introduction of hydraulic fluid into the right-hand end 35 causes the piston 3 to move toward the left, so that the arms 30 are pivoted the dash line position, shown in Fig. 4, it being understood that movement of the cylinder 35 toward the left is prevented through the engagement of the stop member. with the end member I3. In this manner, the boom 20 is pivoted through the remainder of its movement toward the right so that an object 18 supported by the cable 24 is'lifted at A and deposited at B. As the boom 20 arrives at thecentral position, indicated by the dot-anddash lines in Fig. 1,'it is subjected to the force of gravity and tends to fall. 7 However, the pressureresponsive valve (i6 becomes active, due to increased pressure developed in the line 60, and the valve controls the return of the fluid to the reesrvoir 63 and thus regulates the descent of the boom, so as to ease the load 10 gradually onto a supporting structure, as indicated at B.

While I have herein shown and described the hoisting apparatus as embodied in a preferred construction, by way of example, it will be un-' derstood that various modifications may be made in the structure without departing from the spirit or scope of the invention. Therefore, without limiting myself in this respect, I claim:

1. In a hoisting apparatus: a support; a boom pivoted transversely of said support and adapted tomove through an arc to opposite, substantially horizontal positions and to positions intermediate said opposite positions, said boom having an arm projecting from its pivotal end; cam means pivoted on said support and adapted when pivoted in one direction to engage the free end of said arm so as to pivot the same and said boom through a portion only of said arc; and power means operatively connected to said cam means for pivoting the same, said power means being also connected to said arm and operative in response to the completion of the pivotal movement of said cam means in said one direction to pivot said arm and said boom through the remainder of the said arc. I

2. In a hoisting apparatus: a support; a boom pivoted transversely of said support and adapted to move through'an arc to opposite, substantially horizontal positions and to positions intermediate said opposite positions, said boom having an arm projecting from its pivotal end; cam means carried by and movable on said support and adapted, when moved in one direction, to engage the free end of said arm so as to pivot the same and said boom through a portion only of said arc; and hydraulic means carried by and movable on said support and operatively connected to said cam means for moving the same, said hydraulic means being directly connected to said arm and operative in response to completion of movement of said cam means in said one direction to pivot said arm and said boom through the remainder of said arc.

3. In a hoisting apparatus: a support; a boom pivoted transversely of said support and adapted to move through an arc to opposite, substantially horizontal positions and to positions intermediate said opposite positions, said boom having an arm projecting from its pivotal end; cam means pivoted on said support and adapted to engage the free end of said arm so as to pivot the same and said boom through a portion only of said arc; a hydraulic jack including a cylinder, a piston and a piston rod, said rod being pivotally connected to said arm; means for mounting said jack cylinder for movement toward and away from the pivotal axis of said arm, said cylinder being adapted to be moved in one direction in response to fluid pressure applied between one end of said cylinder and said piston; link means operatively connected between said cylinder and said cam means and adapted to move said cam means in response to movement of said cylinder in said one direction to an operative position; and stop means on said support engageable with said cylinder to retain the same in its operative position so that fluid under pressure thereafter introduced between said end of the cylinder and the piston causes said piston and rod to move in a direction opposite to said one direction so as to pivotsaid boom through the remainder of said arc.

4. In a hoisting apparatus: a support; a boom pivoted transversely of said support and adapted to move throughan arc to opposite, substantially horizontal positions and to positions intermediate said opposite positions, said boom having an arm projecting from its pivotal end; cam means pivoted on said support and adapted to engage the free end of said arm to pivot the same and said boom through a portion only of said arc; a hydraulic jack including a cylinder, a piston and a piston rod, said rod being pivotally connected to said arm; means for mounting said jack cylinder for axial movement toward and away from said arm, said cylinder being adapted to be moved in one direction in response to fluid pressure applied between one end of said cylinder and said piston; link means operatively connected between said cylinder and said cam means and adapted to pivot said cam means in response to movement of said cylinder in said one direction to an operative position; and stop means carried by and movable with said cylinder and engageable with said support for retaining said cylinder in its said operative position so that fluid under pressure thereafter introduced between said'end of the cylinder and the piston causes said piston and rod to move in a direction opposite to said one direction so as to pivot said boom through the remainder of said arc.

5. In a hoisting apparatus: a support; a boom pivoted transversely of said support and adapted to move through an arc to opposite, substantially horizontal positions and to positions intermediate said opposite positions, said boom having an arm projecting from its pivotal end; cam means pivoted on said support and adapted to engage the free end of said arm so as to pivot the same and said boom through a portion only of said arc; a hydraulic jack including a cylinder, a piston and a piston rod, said rod being pivotally connected to said arm; means for mounting said jack cylinder for axial movement toward and away from said arm, said cylinder being adapted to be moved in one direction in response to fluid pressure applied between one end of said cylinder and said piston; link means operatively connected between said cylinder and said cam means and adapted to pivot said cam means in response to movement of said cylinder in said one direction to an operative position; stop means pivotally mounted on said movable cylinder and adapted to bepivoted into engagement with said support to retain said cylinder in its said operative position so that fluid pressure thereafter introduced between said end of the cylinder and the piston causes said piston and rod to move in a direction opposite to said one direction so as to pivot said boom through the remainder of said arc; and means for pivoting said stop means.

6. In a hoisting apparatus: a support; a boom pivoted transversely of said support and adapted to move through an arc to opposite, substantially horizontal positions and to positions intermediate said opposite positions, said boom having an arm projecting from its pivotal end; cam means pivoted on said support and adapted to engage the free end of said arm so as to pivot the same and said boom through a portion only of said arc; a hydraulic jack including a cylinder, a piston and a piston rod, said rod being pivotally connected 7,. tcrsaid; arm; means formountingsaid jack. cylinder: for axial. movement toward and away from said. arm, said cylinder being adapted to be moved one direction. in response to fluid pressure applied between one end of said cylinder and said. piston; link means operatively connected between said cylinder and said cam means and adapted to pivot. said cam means in response tomovement of said cylinder in said one direction .to an operativeposition; stop means pivotally mounted on said movable cylinder and adapted to bepivoted into engagement with said support to retain said cylinder in its operative position so that fluid pressure thereafter introduced. between said end of the: cylinder and the piston causes said piston and. rod to move in a direction opposite to said onedirection so as to pivot saidbocmthrough the remainder of said are; and. means operatively connected to and operated: by said arm during. thepivotal movementbf said arm through. said portion of said are. for: pivoting, said: stop means.

7. In a hoisting apparatus: a support; a boom pivoted'transversely of said support and adapted tomovethrough an arc to" opposite, substantially horizontal. positions, and to positions intermediate said? opposite positions, said boom having an arm projecting from its pivotal end; cam meanspivoted on said support and adapted to engage; the free end of said arm so as to pivot thesame. and said boom through a portion only of saidarc; a hydraulic jack including a cylinder, a. pistonslidable in the cylinder, and a piston rod pivotally connected to said arm; means for slidably mounting said. cylinder on said. support to adapt; it to slide'axially in a direction toward the pivotal. axis; of said arm to an operative po sition; a first: stop means fast on said cylinder and engageable with said support to limit sliding movement of" said cylinder. in said direction; a link. connected between said cylinder and said carrrmeans and adapted toimove said cam means iniresponse to movement of said cylinder'to said operative position, said cylinder being movable in response; to fluid pressure applied between an end thereof and said piston; a second stop means pivotedon said cylinder and adapted, when pivotedr to: one position, to engage. said support to retain said. cylinder in. its-operative position; a

slide member. adaptedwhen slid in. one direction, to pivot saidsecond stop means to: said position; and. a push-baroperatively connected between said slide member and. said arm and. operative in response topivotal movementv of saidv arm through saidportion of said arc toactuate said slidemember, fluidpressure introduced between said end of the cylinder and said pistonjsubsequent to movement of the cylinder to said. opera.- tive position causing said pistonandrod tomove in a direction away from. the pivotal axisrof said arm so that said boom is pivoted through. the remainder of said are.-

8. An apparatus as defined'in; claim 7, including bracket arms on said support,- said cylinder being pivotally and-slidablyconnected. between said bracket arms.

9. An apparatus as defined in. claim '1, including bracket. arms on said support, saidarms having slots, and. a pin on said cylinder pivotally and slidably arranged in said slots, one end, of said slots constituting said first stop. means.

10. An apparatus as defined in claim '7, in which said second stop means consists of an. arm pivoted to said cylinder and having a follower, and in which saidslide member has an inclined end engageable with said follower to pivot said arm.

11. An apparatus as defined in. claim '7, in which said hydraulic jack is adapted to pivot said boom to a substantially vertical position, pivotal movement beyondsaid vertical position being augmented by the force of gravity, and in.- cluding a hydraulic system. in which said hydrauliccylinder is disposed, and apressure-responsive valve in said system for controllingthe exhaust of fluidfrom said cylinder so as to con: trol the rate of descent of said boomi LOURIEL. EAKIN".

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

UNITED STATES PATENTS Number Name Date 2,353,655 Day July 18,1944 2,360,654. Day Oct. 17,..1944 2,433,598 Chadwick Dec. 30,1947

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