US2088648A - Manual loading hoist for trucks - Google Patents

Description

A. E. HANSEN MANUAL LOADING HOIST FOR TRUCKS Aug. 3, 1937.

Filed Aug. 4, 1936 2 sheets -sheet l Aug. 3, 1937. A. E. HANSEN 2,088,643

' MANUAL LOADING HOIST FOR TRUCKS' Filed Aug. 4, 1956 2 Sheets-Sheet 2 Er n gwucm I Arthur E. Hansen qmz'. i

Patented 3', 1937 MANUAL LOADING nors'r FOR muons Arthur E. Hansen, Seattle, Wash, assignor to Young Iron worka'seattle, Wash, 2. corporation of Washington Application August 4, 1936, Serial No. 34,153

3 Claims.

My invention relatesuto load hoists for use on trucks, to lift heavy loads from ground level up to the levelof the floor of the truck, and to lower such loads. My present invention is an improvement upon my Patent No. 1,929,112.

In that patent I disclosed such a hoist which was both power operated and manually operated. In the power operated unit the load is always under control through the hydraulic unit employed. Power units as disclosed in my previous patent are entirely dependable and satisfactory,

but require special installation, and the cost of the hydraulic unit is comparatively large. It is therefore necessary to provide such a hoist with manual operating means for certain installations whereit is impracticable to install power means, either because of the first cost or because of the difiiculty of installing thepower unit.

In the manually operated form it was intended that the load should be controlled through a. ratchet and brake. In practice,,however, it was found that operators would become careless, the

brake would be imperfectly set, and when theratchet dog was thrown out the load would begin to drop and could not be caught by the brake. Furthermore, the crank handle employedjto lift the load would sometimes be left in' place, and when the load started to lower, would begin to rotate rapidly'and would constitute a source of danger to the operator. It is absolutely essential that such a manual hoist have means incorporated in it to prevent the load running away and dropping, for not only is this dangerous to the operator, as pointed out above, but in most instances the load will be damaged or destroyed.

It isa general object of the present invention to provide manual means for hoisting, and lowering such a load in conjunction with a truck body by means of which the load is at all times under perfect control, and can never drop accidentally, being always held automatically at any given elevation or position unless manually operated to raise or lower it, and being then automatically held in any new position.

A further object is to provide mechanism of the general character indicated, which shall be simple, which will make it possible to employ simple spur .gears for power reduction in the hoist, and which can be readily applied as a unit to the truck body, and which will be capable of operation by unskilled operators or truck drivers, and which, moreover, will be rugged and dependable, and of low cost.

My invention comprises the novel parts, and the novel combination and arrangement thereof with respect to a truck body, as shown in the accompanying drawings, described in this specification, and as will be more particularly pointed out by the claims which terminate the same.-

In the accompanying drawings I have shown my invention incorporated in a form which at present is preferred by me.

gure .1 is a. side elevation of the rear end of a truck, showing my invention incorporated therein;

Figure 2 is a rear'elevation of such a truck,

and of my hoist.

Figure 3 is an axial section through the hoist.

Figures 4 and 5 are respectively a detail section and a detail elevationon the respective lines 44 and 5-5 of Figure 3.

The truck body is illustrated at 9 with its'floor level at 90. It is suitably supported upon the chassis SI of the truck, the rear wheel 92 of which-is shown resting upon the ground'at G. A platform 8-is supported at the swinging end of. a. lifting arm I pivotally' mounted at l0 upon the truck body or chassis or preferably upon a framework composed of spaced plates 2 and 20 which house the hoist unit, and which are intended to be secured to the chassis or to the truokbody, or both. The platform 8 is ralsed as the lifting, arm I swings upwardly from the round level G to the level of the floor 90 of the truck body. -It is suitably maintained upright while hoisting, as for example by an upright arm 80,-the platform 8 and arm 80 being pivotally mounted at 8i upon the swinging end of the hoisting arm I, and by a parallel arm 82 which is pivoted at 83 to the upright arm 80, and at the axis of the hand crank C, as will be made clear hereafter. A chain 84 from the upright arm 80 to the platform 8 supports the outer end of the platform and permits the latter to'be swung uD- ward as an endgate when at the level of the floor 90. However, in so far as my hoist unit is con-- cerned, the platform may be of any type and may,

be otherwise supported and guided for movement between its elevated and its lowered position; the presentinvention resides in the manual operating means for installation upon a truck, to

operate any suitable load elevator.

Formed on the lifting arm I or secured thereto,

of the clutch elements and of the gear train winethe clutch elements grip the ratchet wheel. Should the operatorlet goof the crank, the weight operates the clutch element 3, but instead. of the two clutch elements engaging-each other they are arranged to clamp between them a- To effect this clamping action ratchet wheel i. the clutch elements are formed one witha screw element 3i, the other with a nut element 32 threaded on the screw element 3 l, and the clutch element 30 is formed with a hand crank connection 33, whereon the hand crank C. may be. secured, permanently or temporarily. The crank connection 33 is preferably polygonal-in shape,

as indicated in Figure 5, whereby a removable hand crank'may fit thereon, Whenthe crank is turned it will tend to turn-this element 3.0

and the nut 32 formed therewith, relatively to the clutch element 3 andits screw 3L:

when the hand crank connection 38 is turned in a direction to hoist the platform 8 the'eifect of the interengaged nut 32 and screw 3| is to draw the two clutch elements 3 and ill towards each -other. The ratchet wheel I, supported upon and rotatlve about an annular flange 34 of the clutch element 3, is thus clamped between the two clutch elements, and when tightly clamped rotates with them. A ratchet dog ll upon apivot H nxed to one of the plates, and held in engagement at alltimes by a spring 2, permits the ratchet wheel to turn in this direction,- but prevents reverse movement of the ratchet wheel, and consequently of the platform and its load, if any, will tend to reverse the spur gear train, and to rotate the 5 clutch element 3 in a. reverse direction, but the" weight of the crank handle, and indeed the reslstance of the parts,'is ample to effect sufficient relative movement between the screw II and nut 32 to again clamp the ratchet wheel between the 5p clutch elements 3 and 8' and to hold the load in its position, especially as the speed of rotation When'it is desired to lower the load of the gear 15, thus reversed; is high as compared to the speed of rotation of the crank connec-, tion 33.

the crank handle is turned in the reverse direction, tending to unscrew the nut 32 from the screw 3i, and to separate the clutch elements-3 and. The load, however tends to rotate the clutch element 3 '6 faster than the clutch element a is turned, yet

- there is sufiicient unscrewing action to release the clutch elements from the ratchet wheel l, which" is now held against rotation in the dog .40, and to permit this reverse movement, yet theload can c5. never get away from the operator,- for if it shouldtend to turn faster it will cause "the clutch'elh ment 3 to move toward and overtake the clutch element 38, and again to clamp the rawhet wheel 4, which is held in podtionby the dog 40, and

thus the load would be held in. its position.

-"-In order to insure that the clutch element 3 willfollow the clutch element-30 I may provide a lug, as for example the set screw 5, projecting inwardly from the crankv connection 33 or otherwise associated with the clutch ele n 30, and

where the spur gear train described is preferably. I

engageable with a lug 50 carried by a washer 5i keyed to the shaft 16 or an extension thereof, and held in place by the nut 52. If after reverse movement of the crank connection 33, sufficient to engage the lug 5 with the lug 50, the clutch element 8 has not followed the movement of the clutch element to, the engagement of the lugs will insure that the clutch element 3 is moved to follow up the clutch element 36, and in a direction to clamp the ratchet wheel 4.

. A guard 8'5 may be employed to surround the axial portion of the crank C, and this may serve as a pivot support for the arm 82, previously described. This arm may be suitably held upon the guard 85, as for example by the retainer flange 88- (see Figure 3), which is secured to the outer plate 2.

-The entire device is compact, the spur gears are the cheapest and simplestform of gearing to employ, and the entire device may be manufacturedand'installed as a unit, with little or no fitting .to the truck. I

' What I, claim as my invention is -1 Incombination with a truck body hoist having lifting means to elevate a loading platform from; ground level to the level of the truck body floor, a driven shaft coupled to such lifting means,

a dr1vingishaft,'a hand crank therefor, an end of one of said shafts being hollow and the other posed between said two friction plates and mutually clamped thereby, through the action of said threads by rotation of said driving shaft injthe hoisting direction or by rotation of said driven shaft in the lowering directiomfor rotationwith said shafts in the hoisting direction, and

, releasable by-rotation of said driving shaft in the lowering direction; and a dog engaging said ratchet wheel to resist'its rotation in the lowering direction under the influence of the tendency of the driven shaft to be rotated in the lowering direction by the load on said lifting means, after rotation of the driven shaft in the lowering direction has effected clamping of the ratchet wheel between said two friction plates.

2. In combination with a truck body hoist having lifting means to' elevate a loading platform from ground level to the level of the truck body floor, a driven shaft coupled to such lifting means, a driving shaft,'a hand crank. therefonan end of one of said shafts being hollow and the other shaft having an end telescopically received therein, a female thread formed in said hollow shaft end; a male thread cooperating with said female thread and formed on the end of said telescopically received shaft end, a friction plate rigidly fixed to said driven shaft and facing said driving shaft, 8. second friction plate spaced from and facing said first clutch plate and rigidly fixed to said drivingshaft, a ratchet wheel interposed between said two friction plates and mutually clamped :th'ereby, through the action of said threads by rotation of said driving shaft in the hoisting direction or by rotation of said driven shaft in the lowering direction, for rotation with said shafts in the hoisting direction, and releasable by rotation of said driving shaft in the lowering direction, a dog engaging said ratchet wheel .toresist its rotation in the lowering direc-- tion under the influence of the tendency of the driven shaft to be rotated inthe lowering direction by the load on said lifting means, after rotation of the driven shaft in the lowering direction has effected clamping of the ratchet wheel between said two friction plates, an. abutment projecting radially outward from said telescoping shaft end, and a second abutment projecting radially inward from said hollow shaft and engageable with said first abutment upon less than a complete revolution of the driving shaft with respect to the driven shaft in a lowering direction, to effect positive conjoint lowering rotation of said two shafts while the ratchet wheel remains held from such rotation by the dog encaged therewith.

3. In combination with a truck body hoist having lifting means to swing a loading platform from ground level'to the level of the truck body floor, two parallel arms pivotally connected each by one end to such lifting means, a pivot connecting the other end of said lower arm to the truck -body, a gear segment formed on the upper side of said lower arm and-concentric with said lower arm truck body pivot, a pinion coupled with said gear segment, a journal on the truck body for said pinion, pivot means concentric with and surrounding said pinion journal connecting the other end of said upper arm to the truck body, a hoisting and lowering hand crank, a driving member operated thereby and disposed in alignment with said pinion journal, clutch means between said driving member and said pinion operable to transmit lowering and hoisting rotation lowering rotation, and released by lowering rotation of said driving member corresponding to lowering rotation of said driven member.

- ARTHUR E. HANSEN.

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