US2670176A

US2670176A - Hoist

Info

Publication number: US2670176A
Application number: US253531A
Authority: US
Inventors: Fredrick W Coffing
Original assignee: COFFING HOIST Co
Current assignee: COFFING HOIST Co
Priority date: 1951-10-27
Filing date: 1951-10-27
Publication date: 1954-02-23
Anticipated expiration: 1971-02-23

Description

Fel 23, 1954 F. w. coFr-'ING HOIST 3 Sheets-Sheet 1 Filed Oct. 27, 1951 Feb. 23, 1954 F. w. COFFING 2,670,176

HoIsT Filed Oct. 27, 1951 3 Sheets-Sheet 2 INVEN TOR. FRfoK/av I4( (aff/YG Feb. 23, 1954 F W, COFFING 2,670,176

HOIST Filed Oct. 27, 1951 3 Sheets-Sheet 3 IN1/EN TOR. feine/cr W. (oFF/Na Patented Feb. 23, 1954 HOIST Fredrick W. (loilng, Danville, Ill., assigner to Ceiling Hoist Company, Danville, Ill., a corporation Application Uctober 27, 1951, Serial No. 253,531

7 Claims.

The present invention relates to improvements in hoisting apparatus, and more specically to lever operated chain hoists.

In my co-pending application filed March 15, 1951, bearing Serial No. 215,700 I have shown, described and claimed a lever operated chain hoist wherein the hoisting mechanism may be readily and easily shifted to load raising condition, to load lowering condition or to iree running condition when it is the desire of the operator to establish these conditions.

It is one of the objects oi the present invention to provide a chain hoist having characteristics oi the hoist described and claimed in said application, but which may be more simply constructed, shall have fewer operated parts, and which will have the equivalent load lifting power and which may be embodied in a more compact construction.

For the purpose' of disclosing my invention I have illustrated an embodiment thereof in the accompanying drawings in which:

Fig. 1 is a transverse sectional view o! a hoist embodying my invention,

Fig. 2 is a longitudinal sectional view taken on the line 2-2 oi Fig. 1, and y Fig. 3 is a longitudinal sectional view taken on the line 3--3 at Fig. 1, certain oi' its parts being shown in dotted lines for the purpose ci clarity.

Fig. 4 is a fragmentary view showing parts of the hoist in load raising position.

Fig. 5 is the same as Fig. 4, yshowing them in load lowering position with the holding pawl freed.

Fig. 6 is the same as Fig. 5 showing the parts in load lowering position with the load pawl released.

In the embodiment illustrated I provide a housing lll having a front plate closing member il secured in place by suitable holding screws i2 shown in Fig. 2. The housing is provided with an offset portion I3, which provides a housing for the load chain sheave I4, over which is adapted to ride the 'link chain I5. This chain feeds through suitable openings in the bottom oi the offset I3.

The chain sheave i4 is mounted on a shaft IB, one end of which is mounted in a bearing `i'l in the housing l0. On the opposite side oi' the sheave I4 the shaft I6 is provided with an enlarged portion I8 operating in a bearing I8 supported in a dividing wall of the housing I0. The shaft I8 is extended in reduced diameter, and the opposite end thereof extends into a bearing 2|) in the vcover plate Il. Mounted on the shaft extension is a ratchet wheel 2l which is keyed on the shaft I8 and, therefore, is rotatable With the sheave I4.

The housing is provided at its top with a swivel hook 22. the end 23 (see Fig. 2) of which extends through the housing to be engaged by a holding nut 24 for maintaining the hook against vertical displacement.

The ratchet wheel 2| is operated and controlled respectively by handle pawl 25 (see Fig. 2) and a holding pawl 26. The holding pawl is mounted on a stud 21 extending between the side walls of the housing. The end of the pawl is adapted to engage the teeth 21a of the ratchet wheel 2|. This holding pawl is biased in an engaging direction by coiled spring 29 coiled around the stud 21 and having one end bearing against the inside wall of the housing and the other end hooked over the back of the holding pawl.

The load pawl 25 is disposed between and carried by a pair of arms 28 swingably mounted upon the shaft i6 and disposed on opposite sides of the ratchet wheel 2 I The pawl is pivoted upon a stud 30 fixed between the arms 28 and has its free end biased in a tooth engaging direction by coiled spring 3|. One end of this spring is secured to a pin 32 on the inner face of one of the arms 28, and its opposite end is connected to a pin 33 on the inner edge of the pawl.

The free ends of the arms 28 are connected by a link 34 with an oscillating lever arm 35. To this end, one end of the link 34 is pivotally connected by a pin 36 extending between the free ends of the arms 28, and the opposite end extends between bifurcated ends oi the lever arm S5 and is pivotally connected to the lever arm by a pin 31. This lever arm 35 is a part oi' an oscillating shaft 3B (see Figs. 1 and 2) having one end jcurnalled at 39 in a side wall of the housing, and the other end enlarged as at 4l) and extending through a bearing 4I in the cover plate Il, see Fig. l. The outer end of this eniarged portion 40 has a lever arm receiving opening 42 through which may be passed an operating lever arm 43, and which is adjustably slideable through the opening so that the lever length oi the same may be adjusted or the direction of lever operation may be changed by sliding the lever from one extremity to the other. 43a are retainers to avoid passing lever 43 entirely out of lever arm receiving opening 42. The lever arm 43 is maintained in its adjusted position through the medium of a set screw 44.

For controlling the various positions of the holding pawl 26 and the load pawi 25, I provide a reversing ring 46 (shown in Figs. 1 and v2) which is rotatably mounted on an extension 4E of the bearing for the shaft portion I8. This reversing ring is provided with an operating cam 41 (see Fig. 2) for operating and controlling the position of the holding pawl 25. The holding pawi 25 is provided with a pin 48 which projects into the path of a cam 41 to be engaged by said cam when the reversing ring 45 is moved to a predetermined position by spring I.

A cam 49 oppositely disposed relative to the cam 41 (see Fig. 2) on the reversing ring 45 is adapted to control the position of the load pawl 25. This cam is adapted to engage a pin 5I! on the load pawl 25 which extends through a slot 28a in one of the arms 28 and into the path of the cam 45 to be engaged thereby when the reversing ring is moved to predetermined position by spring 5I.

The reversing ring 45 is biased in a direction to cause the cam 41 to engage the pin 48 by a coiled spring 5i, one end of which is anchored to a pin 52 secured in the casing, and the other end of which is connected to a lug 53 on the reversing ring 45. This spring biases the reversing ring 45 in a counterclockwise direction, looking at Fig. 2. The reversing ring 45 is moved in a clockwise direction through the medium of a cam member 54 which is rotatably mounted on a shaft 55 provided with an operating handle 56 which is exterior of the casing. The cam member 54 is adapted when rotated counterclockwise by the handle 56 to engage an arm 51 on the reversing ring and rotate the reversing ring clockwise thereby insuring the disengagement of the

cani members

41 and 49 from their respective pawls.

In order to give an additional kick to the ring to cause the same to rotate counterclockwise in addition to the influence of the spring 5i when the cam member 54 is disengaged from the arm 51, I provide a spring pressed plunger 58 operating in a cylinder 59 and adapted to be engaged and the spring controlling the same compressed by the lug 53 when the reversing ring is moved in a clockwise direction.

It will be observed that by oscillating the hand lever 43 through shaft 38, the operating lever arm 35 will be oscillated, and in turn will oscillate the load pawl carrying arms 28 through the link 34. Said arms will thereby be caused to oscillate the load pawl about the axis of the sheave I4 relative to the teeth Zia oi the ratchet wheel 2I.

For raising the load, as shown in Fig. 4, the reversing ring 45 has been rotated clockwise by the engagement of the cam 54 with the arm 51 to move the cam member 41 and the cam member 43 out of position to engage the holding pawl 26 or the load pawl 25. Thereupon, these respective pawls are adapted to ratchet on the teeth 2 la of the ratchet wheel 2 I. Under these circumstances the holding pawl 26 will be in engagement with the teeth of the ratchet wheel thereby holding the same against clockwise rotation under the influence of a load carried by the load end of the chain l5. If now the handle lever 43 be raised or moved clockwise to the hoist, this will rotate the lever 35 in a clockwise direction and through the link 34 the arms 28 will be raised, thus causing the pawl 25 to ride the teeth 2Ia.. As soon, however, as the direction of movement of the handle lever 43 is reversed, the arms 2B will be lowered in a counterclockwise direction with the pawl 25 biting into the teeth 2 l a of the ratchet 2l thereby rotating the ratchet and with it the chain sheave elevating the load. During this movement the holding pawl will ratchet over the teeth d being, however, in a condition to lock into the teeth as soon as the load is released by releasing the downward pressure on the handle 43. By repeated oscillations of the handle 43 the load will be raised.

If, however, it be desired to lower the load, the handle 5E is moved to the position illustrated in Fig. 5, reversing the position of cam 54 relative to the arm 51, and the coiled spring 5I will bias the reversing ring in a counterclockwise direction, or in a direction to cause the pawl member 41 to engage the pin 4S. With the parts illustrated in Figs. 2 and 6, the holding pawl 2G has taken the load, being in engagement with one of the teeth 2id of the ratchet Wheel 2| and the reversing ring has been biased to the position illustrated in said figures. With the parts in this position, by elevating the handle 43 and, accordingly, rocking the pawl carrying arms 28 upwardly, the pawl 25 being free from the load drag, and due to the position of the cam member 49, will ride thereover out of engagement with the teeth 2 la.

Due to the fact that the pin 53 in load pawl 25 has ridden onto the top of the cam 49, the reversing ring is free to be moved further in a counterclockwise direction to cause the cam 41 to lift the pin 4B on holding pawl 26, as shown in Fig. 5. The lever 43 having been raised, a slight downward movement thereof will eiect. a corresponding slight downward movement of the arms 28. The load pawl will then be cammed forwardly to engage the next tooth of the ratchet and by slightly taking the load 01T the holding paal 25 by this reverse movement. said holding pawl will be kicked out oi tooth engagement by the cam member 41 engaging pin 48. Upon again raising lever 43, with the pawl 25 in engagement with the teeth 2 I a, the load may be lowered thereby, the lowering action being controlled by the lever 43 and pawl 25. Accordingly, by continued operation of the lever 43 in ratchet style, the load may be controlledly lowered step by step.

For permitting the ratchet wheel 2| to rotate freely and thereby permit free chaining of the hoist with no load thereon, I provided a throwout means operable from the exterior o the casing to throw out the handle pawl 25, as shown in Fig. 3. This throw-out means comprises a spring arm 58a iixedly secured by an eye to the pin 59a and biased by its inherent resiliency into an inoperative position. The spring arm extends downwardly past the pin 5I) and its lower end is adapted to be engaged by an operating lever mounted interiorly of the casing on the inner end of a rotatable shaft 5I. This shaft extends to the exterior of the casing and carries an operating handle E2. Therefore, when the operating handle 62 is operated in a counterclockwise direction it overcomes the bias of the spring arm 58a and moves the same against the pin 5U. However, when the operating lever is moved in the opposite direction, the natural bias of the spring arm 58a will cause its movement in a direction to release pin 50 and the load pawl 25.

Thus, for the free chaining operation, with no load on the hoist and with lever 43 in any position, but with handle 5B in load lowering position, the handle 62 may be swung in counterclockwise direction. This rotates lever 6i) to force the spring 58a clockwise about pin 59a to operating engagement with pin 50 of pawl 25. This action will lift pawl 25 free of engagement with the ratchet teeth 2Ia. Thus, with the holding pawll awaits maintamed in disengaged'position by the cam 41 and the load pawl 25 maintained in disengaged position by the spring arm 58a, the load chain is free to move in either direction.

The invention claimed is:

1. A lever operated chain hoist including in combination a chain sheave, a rotatable ratchet wheel controlling the rotation of said sheave, means for restraining said Wheel from rotating in one direction, a load patvl carrying arm oscillatable about an axis coincident with the axis of said ratchet wheel, a load pawl pivotally mounted on said arm and engageable with the teeth of said ratchet wheel, a pivotally mounted operating lever arm, a link connecting the free end of said operating lever arm with the free end of said load pawl carrying arm, and means for oscillating said operating lever arm.

2. A lever operated chain hoist including in combination a chain sheave. a shaft on which said sheave is mounted, a ratchet wheel mounted on said shaft, a pivotally mounted holding pawl engageable with the teeth of said ratchet wheel, means for biasing said holding pawl into engagement with said ratchet wheel, a load pawl carrylng arm oscillatably mounted on said shaft, a load pawl pivotally mounted on said carrying arm, means for biasing said load pawl into engagement with said ratchet Wheel, an operating lever arm for oscillating said load pawl carrying arm, means for pivotally mounting one end of said operating lever arm, a link connecting the opposite end of said operating lever arm with the free end of said load pawl carrying arm, a handle carried by the pivotal mounting means of said operating lever arm for oscillating said operating lever arm, and a reversing ring oscillatable about the axis of said shaft for controlling the effectiveness of the biasing means oi said pawls.

3. In combination. a load suporting wheel having ratchet teeth, a holding pawl engageable with said teeth, a load pawl engageable with said teeth and oscillatable about the axis of said wheel for controlling the rotation thereof. means for normally biasing said pawls in rachet tooth engaging direction, a movable cam member normally biased to holding pawl engagement for maintaining said holding pawl in non-engaging position, a manually operable member for locking said cam against its bias engagement with said holding pawl, a pivotally mounted spring arm mounted for engagement with said load pawl, and a manually operable lever connected with said spring arm for moving said arm into engagement with said load pawl in a direction to move the same out of engaging position with respect to said ratchet teeth.

4. A lever operated chain hoist including in combination a chain sheave, a rotatable ratchet wheel controlling the rotation of said sheave, a pivotally mounted holding pawl normally biased into engagement Awith the teeth of said ratchet wheel, a load pawl carrying arm pivotally mounted about the axis of said sheave and extending radially therefrom, a load pawl pivotally mounted on said arm and engageable with the teeth of said ratchet wheel, a handle operated lever arm pivotally mounted adjacent the periphery of said sheave and said pawl carrying arm, a link connecting the free ends of said lever arm and pawl carrying arrn, whereby said pawl carrying arm will be oscillated about the axis of said sheave upon oscillation of said lever arm about an axis adjacent thereto, and a spring connecting said load pawl and pawl carrying arm for normal- 6 1y biasingfsaid load pawl m ratchet tootli engagement.

5. A lever operated chain hoist including a chain sheave, a housing mounting said sheave for rotation therein, a rotatable ratchet tooth wheel rotatable with and oifset axially of said sheave within said housing, a holding pawl pivotally mounted in said housing normally biased into ratchet tooth engagement for restraining said wheel from rotation in on-e direction. a load pawl carrying ann pivotally mounted axially of said ratchet wheel and adjacent thereto to extend radially therefrom and oscillate thereabout within said housing, a load pawl pivotally mounted on said arm normally biased into ratchet tooth engagement, a handle operated lever arm pivotally mounted Within said housing closely adjacent said ratchet wheel and pawl carrying arm, and a, link mounted within said housing connecting the free end of said lever arm with the free end of said load pawl carrying arm, whereby oscillation of said lever arm Within said housing will effect oscillation of said pawl carrying arm and load pawl about the axis of said sheave.

6. A lever operated chain hoist including a chain sheave, a housing mounting said sheave for rotation therein, a rotatable ratchet tooth wheel rotatable with and offset axially of said sheave Within said housing, a holding pawl pivotally mounted in said housing normally biased into ratchet tooth engagement for restraining said wheel from rotation in one direction, a load pawl carrying arm pivotally mounted axially of said ratchet wheel and adjacent thereto to extend radially therefrom and oscillate thereabout within said housing, a load pawl pivotally mounted on said arm normally biased into ratchet tooth engagement, a reversing ring mounted for concentric movement about the axis of said sheave having opposed cam lobes, a spring for biasing said ring under tension in a direction for camming engagement with said pawls to alternately move them out of ratchet tooth engagement, a manually operated control member for locking said ring in inoperative position against spring tension, a handle operated lever arm pivotally mounted within said housing closely adjacent said ratchet wheel and pawl carrying arm, and a link mounted within said housing connecting the free end of said lever arm with the free end of said load pawl carrying arm, whereby oscillation of said lever arm within said housing will effect oscillation of said pawl carrying arm and load pawl about the axis of said sheave.

7. A lever operated chain hoist including a chain sheave, a housing mounting said sheave for rotation therein, a rotatable ratchet tooth wheel rotatable with and offset axially of said sheave within said housing, a holding pawl pivotally mounted in said housing normally biased into ratchet tooth engagement for restraining said wheel from rotation in one direction. a load pawl carrying arm pivotally mounted axially of said ratchet wheel and adjacent thereto to extend radially therefrom and oscillate thereabout within said housing, a load pawl pivotally mounted on said arm normally biased into ratchet tooth engagement, a reversing ring mounted for concentric movement about the axis of said sheave having opposed cam lobes, a spring for biasing said ring under tension in a direction for camming engagement with said pawls to alternately move them out of ratchet tooth engagement, a manually operated control member for locking said ring in inoperative position against spring tension. a

kickback spring element operably associated with said reversing ring for additionally urging it in the direction of its spring bias upon release thereof by said manually operated control, a handle operated lever arm pivotally mounted within said housing closely adjacent said ratchet Wheel and pawl carrying arm, and s. link mounted within said housing connecting the free end of said lever arm with the free end of said load pawl carrying arm, whereby oscillation of said lever arm Within lo said housing will effect oscillation of said pawl carrying arm and load pawl about the axis of said sheave.

FREDRICK W. COFFING.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 552,044 Crocker Dec. 24, 1895 1,862,331 Cofiing June 7, 1932 2,480,303 Pennell Aug. 30, 1949