US3047114A - Hoist construction - Google Patents

Description

Jul 31, 1962 H. c. STEVENS, JR

HOIST CONSTRUCTION 4 Sheets-Sheet 1 INVENTOR. HOWARD C. STEVENS JR BY fla -wag M Filed July 18, 1958 ATTO RNEYS y 1962 H. c. STEVENS, JR 3,047,114

HOIST CONSTRUCTION Filed July 18, 1958 4 Sheets-Sheet 2 INVENTOR. HOWARD C. STEVENS JR.

BY V ZgI w a/ ZjAzv v ATTORNEYS y 1952 H. c. STEVENS, JR 3,047,114

HOIST CONSTRUCTION I Filed July 18, 1958 4 Sheets-Sheet 3 IN VEN TOR.

HOWARD C. STEVENS JR- AT TO RN EYS y 3 1962 H. c. STEVENS, JR 3,047,114

HOIST CONSTRUCTION Filed July 18. 1958 4 Sheets-Sheet 4 FIG.7

INVENTOR. HOWARD C. STEVENS JR ATTO NEYS United States Patent G 3,047,114 HOIST CONSTRUCTION Howard C. Stevens, Jr., Muskegon, Mich., assignor t Manning, Maxwell & Moore, Iuc., Muskegon, Mich, a corporation of New Jersey Filed July 18, 1958, Ser. No. 749,489 7 Claims. (Cl. 192-16) The present invention relates broadly to hoist constructions, and is more particularly concerned with a new and improved lever-operated chain hoist embodying a novel structural arrangement permitting free-Wheeling of the hoist.

One important aim of the present invention is to provide a hoist construction comprised of a minimum number of readily fabricated parts which may be assembled and disassembled with considerable ease. I

Another object of this invention lies in the provision of a lever-operated hoist having a unitary main'body portion which houses therewithin handle and sprocket shafts mounted in general vertical alignment and producing a chain hoist structure characterized by minimum vertical and horizontal outlines.

Another object of the invention is to provide a hoist wherein the pinion shaft is adequately supported at one end without reliance upon bearings mounted in the hoist cover or the use of a split hoist body portion and wherein new and improved means are embodied presenting a substantially continuous thrust surface against which the pinion may operate.

A further object of the present invention lies in the provision of a hoist construction in which the internal parts are effectively sealed against the entrance of deleterious materials, the sealing means further functioning to maintain the hoist handle in alignment upon the hoist body portion. v

A further object of the invention is to provide a hoist embodying novel means for temporarily disabling the lifting mechanism so that the load chain may be pulled through the hoist in either direction by hand, one form of such means being a cam arrangement preventing locking of the hoist in an open brake position and another form a pawl construction formed and arranged to prevent failure of the pawl in the event foreign materials were accidentally lodged between the pawl handle and the hoist frame.

Other objects and advantages of the invention will become more apparent during the course of the following description, particularly when taken in connection with the accompanying drawings.

In the drawings, wherein like numerals are employed to designate like parts throughout the same:

FIGURE 1 is a side elevational View, with parts in section, showing a hoist constructed in accordance with the principles of this invention;

FIGURE 2 is a vertical sectional view taken substantially along the line IIlI of FIGURE 1;

' FIGURE 3 is a vertical sectional view takensubstantially along the line III-III of FIGURE 1;

FIGURE 4 is detail sectional view of a preferred form of thrust washer employed with the pinion shaft of the new and improved hoist;

FIGURE 5 is an end view, with parts broken away, to show the action of the ratchet wheel pawl and load brake pawl during freewheeling;

FIGURE 6 is afragmentary sectional view of a modified form of hoist freewheeling construction; and

FIGURE 7 is an end view, with parts broken away, of the hoist parts of FIGURE 6.

Referring now to the drawings, there is shown in FIG- URE 1 a hoist designated generally by the legend A and constructed to include a one-piece housing or main frame 16 closed at one end by a cover member 11 and at its opposite end by a hand lever assembly 12 with which is associated a hand wheel 13. Supporting the hoist is a suitable hook 14 received in a swivel connection 15 provided in the upper portion of the housing or main frame 10.

A particular advantage of the one-piece main frame is that the shaft and other structure housed therewithin is maintained in correct alignment at all times. Such structure includes a load sprocket or lifting member 16b having a shaft portion 16 rotatably supported in bearings 17, the sprocket being shaped to accommodate a suitable load chain 18. The lifting member is located within a downwardly opening recess or pocket 19 through which the chain 13 depends, and said chain is provided at its load carrying end with the conventional load hook (not shown). Attachment of the chain to the hoist structure is efiected by a chain anchor designated generally at 20 and to be described in detail later.

Formed integrally with the load sprocket shaft 16 are gear teeth 21 meshing with a pinion '22 integral with a load brake or pinion shaft 23 mounted for rotation in bearings 24 and 25. It may be noted that all load carrying bearings are supported by the housing or main frame 10, and particular reference is now made to the bearing 24. Said bearing is of semi-circular shape, and as appears in FIGURE 3, is received within a bore 26 machined or otherwise formed in the frame structure 10. The bearing 24- protrudes from the partial bore 26 and is maintained against rotation by lugs 27 formed interiorly of the cover 11. The cover further prevents axial movement of the bearing 24 and a boss 28 provided on the cover 11 restricts axial displacement of the load brake shaft 23. It may be seen that by relieving the bearing 24 in the area designated by the numeral 29 that space requirements are substantially reduced, and since the forces produced by the gear action are exerted generally radially outwardly of the relieved portion 29, satisfactory results are obtained therefrom. In addition minimizing the space requirements, the bearing 24 provides outboard support for the pinion shaft 23 without the necessity of a bearing in the cover 11. The bearing 24 may be located in the position shown after the pinion 22 and shaft 23 are positioned in the hoist body 10, and further, adequate shaft support is obtained without resort to a split main hoist frame.

The load or pinion shaft 23 is adapted to be driven by a rotatable and axially movable driving member or load brake nut 30 cooperating with friction discs or washers 31 and '32 positioned against opposed surfaces of a loosely mounted ratchet wheel 33. Secured to the shaft 23 is a brake flange 34. A preferred manner of preventing axial and rotational movement of the flange relative to the shaft is by use of diametrally opposed flattened areas on the shaft engaging a similarly flattened hole in the flange. To permit axial movement of the driving member 30 with respect to the shaft 23, the driving member 30 is provided with an internally threaded bore 35 cooperating-with helically formed threads 36 on the shaft 23. It may thus be seen that when the member 30 is rotated in a load lifting direction, it screws along the threads 36 on the load shaft 23 compressing the friction washers 31 and 32 against the brake flange or thrust disc 34 until its axial movement is blocked, whereupon it rotates the shaft in a direction effective to raise the load carrying end of the chain 18.

Substantial thrust is exerted upon the load shaft 23 during operation of the hoist A, and novel means in the form of a continuous thrust surface has been provided against which the pinion 22 may operate. Referring particularly to FIGURES l and 4, there is included a thrust washer and shield assembly 37 located in a bore 38 in 3 the housing and axially inwardly of the bearing 24 supporting one end of the shaft 23. The thrust washer is comprised of two sections 39 as shown in FIGURE 4 constructed to be separably connected by a tongue and groove arrangement. identical, only one is illustrated. Each section 39 is formed of three washers a, b and c initially cut across their diameters and then assembled and welded or otherwise secured together in a manner that the radial edges of the Washers a and c overlap the washer b to provide on each section 39 a tongue d and a groove e. According the tongue d of one section into the groove e of the other section, and the tongue of the other section'in the groove of the first section. This set permits the thrust washer and shield assembly 37 to be assembled on the shaft 23 before said shaft is inserted or positioned in the hoist body or frame 10. The thrust washer fits relatively loosely in the bore 38 of the housing, whereby by reason of a limited clearance on the shaft 23 and a limited clearance in the housing bore 38, in combination with the novel washer construction, no substantial relative movement of the two sections 39 of the washer 37 can occur after assembly. In addition to substantial assembly advantages, the thrust washer 37 provides an essentially continuous thrust surface against which the pinion 22 may operate during use of the hoist A of this invention.

In the form of the invention presently being described,

. peripheral teeth 41 on the ratchet wheel 33 are engaged by a pawl 42 resiliently urged by spring means 43 movable within a sleeve 44 carried within a bore 86 in the housing 10. During the load raising action, the pawl 42 moves freely over the teeth Men the ratchet wheel 33, the pawl oscillating vertically in the sleeve 44. However, as soon as the raising action is stopped, the pawl engages the ratchet teeth and thereby maintains the ratchet wheel 33 stationary with respect to theframe or body 10. The pressure which is then developed due to the load torque and transmitted through the helical threads 36 on the shaft 2 2, creates friction between the discs. 31 and 32 and the driving member and brake flange 34.

The driving member or loadbrake nut 30 is provided with peripheral teeth 45 for engagement with a pawl 46 carried upon a shaft 47 received in bearings 48 supported in bore 49 of the handle assembly 12. As appears also in FIGURE 5, the pawl 46 is acted upon on opposite side surfaces by spring means 50, preferably of thehairpin-type shown through rotation of a hand lever 51 associated with a cam 52. The lever 51 controls reversal of the handle ratchet mechanism and may take either an up or down position as shown.

To temporarily render the load brake nut 30 ineffec tive in order that the chain 18 may be pulled through the hoist in either direction by hand, there is provided a cam member 53 secured to the shaft 23 closely adjacent the driving member or load brake nut 30. As is shown in FIGURE 2, the cam 53 is provided with a generally centrally located bore 54 having spaced at 90 degrees therealong key slots 55 permitting adjustment of the cam with respect to the shaft 23 and locking thereon.

Four positions of adjustment are thereby provided, and

additional four point adjustment is obtained by reversal Since the sections are essentially ingly, the thrust washer 37 may be assembled by insertof the cam 53 to utilize detent notches 56 provided on the cam circumference. Engageable with the detent notches 56 is ball means or the like 57 resiliently urged by spring means 58 movable within. a housing 59 of general U-shape in cross-section secured to the load brake nut 30 by screws or similarrmeans 66. While the element 57 is shown as a ball, any suitably shaped detent means may be employed, as for example, anon-rotatable pin of round, square or other desired cross-section. Carried also upon the circumference of the cam 53 is :1 lug 61 preventing locking of the load brake nut in an open brake position. Specifically, the lug 61 is so spaced upon'the cam 53 that should a sudden acceleration be applied to the handle A bk 12 in lowering direction, the load brake nut cannot back away rapidly and lock in the open brake position. Stop means for the lug is provided by one of the screws 60 holding the bracket or, housing 59 upon the load brake nut face.

The cam 53 is rigidly connected to the hand wheel: 13 by means of a pin or the like 62 received in a hole or opening 63 in said cam and passing through a thrust washer 64 abutting said hand Wheel. A generally domeshaped bearing 65 is located between the handle assembly 12 and the hand wheel 13, and this bearing has been found effective in combination with a ring bearing 66 radially outwardly of the load brake nut 30 to hold the handle assembly '12 in proper alignment with respect to the frame or body housing 10, and also as effective means to prevent the entrance of deleterious substances into a the operating mechanism of the hoist A. It isto be noted that the ring bearing 66is positioned in part between a collar portion 67 on the handle assembly 12 and a rim portion 68 on the body housing. A circumferential groove 69 is formed along the inner diameter of the bearing 66 providing a lip 70 at approximately the corner of the bearing. A material found preferable to comprise the bearing 66 is a plastic of the nylon or Teflon I character, and the function of the lip 70 is to provide a very effective seal against the cylindrical surface 67 of the handle assembly.

A feature of the particular cam, hand wheel and re lated structure disclosed is ease of assembly and disassembly. Specifically, the cam 53 is first positioned'upon the shaft 23 in one of the eight adjustable positions described, and the thrust washer 64 also placed over the shaft. The handle assembly 1 2 is then moved axially of the shaft to locate the cylindrical collar 67 inwardlyof the bearing 66 and upon the shaft 23. The pin means 62 is then driven tightly into the hand wheel 13, and as so located protrudes in order that when the hand wheel is next placed upon the shaft and through its external beartive motion between the shaft 23' and hand wheel 13 is efie'ctively prevented by the pin 62, and the cam 53, and the key (not shown) located in the key slot therein. 7

An additional structural feature of the present invention is the means for effecting securement of the second part of the load chain 18 to the hoist housing or frame 10. The chain anchor 20comprises a yoke .74 supported upon a pin or its equivalent passing entirely through the yoke 74 and last link of the load chainwit-hin bored openings 76 a'nd.77 within the hoist main body. Screw means 78 prevents axial dislodgment of the pin 75. Adequate support for the pin 75 is provided by the hoist frame in the manner disclosed, and by forming saidpin of a harda point between the inner wall of the hoist frame and the outer edge of the yoke 74.. It is now readily apparent that provision of the yoke arnanged in the manner disclosed avoids the necessity of closing the frame casting" in at this point to nearly fit the chain. This is disadvantageous from a production standpoint, but notwithstanding this, the frame is normally constructed of aluminum and experience has shown that weaknesses develop therein even before the full strength of the chain is developed.

The operation of the disclosed hoist A may be sum- V marized .as follows. During a raising action, thehand V lever 51 is'moved to the up position engaging the pawl 46 with the teeth 45 on the driving member 30. When the handle assembly 12 is moved in a counter-clockwise direction, the driving member or load brake nut 30 screws along the threads 36 on the load shaft 23, compressing the friction washers 31 and 32 against the thrust disc or flange 34 until its axial movement is blocked, whereupon the driving member rotates the shaft 23 in a direction effective to raise the load carrying end of the chain 18. During the lowering action, the hand lever is moved to the down position, and upon clockwise rotation of the handle assembly 12, the pawl remains fully engaged with the ratchet wheel teeth 41, but since the motion is reversed, the driving member 30 moves axially away from the friction surfaces 31 and 32. This allows the shaft 23 to rotate, permitting rotation of the sprocket 16b in a lowering direction until the load brake nut returns to its engagement with the friction surfaces. This would occur if handle movement was stopped, since the torque exerted by the load is transmitted through the shaft 23 to move the load brake nut into engagement with the friction surfaces.

To free wheel the hoist, that is to temporarily render the load brake nut 30 ineffective so that the chain 18 may be pulled through the hoist in either direction by hand, the thumb lever 51 is first placed in a down position which engages the pawl 46 with the ratchet teeth 45 on the load brake nut 30. The hand wheel 13 is thereupon rotated a minor amount either clockwise or counterclockwise to cause axial movement of the load brake nut 30 from the friction discs 31 and 32 and the ratchet wheel 33. The ball means 57 will then engage a detent notch or surface 56 on the cam 53 thereby locking the load brake nut 30 to the cam 53 and thereby to the shaft 23. The parts named will thereupon rotate in unison, and since the ratchet wheel 41 and pawl 42 are in engagement continuously, no braking action will occur until a load greater than normal chain movement is imposed upon the hoist. Should this occur, the detent ball 57 will be forced out of the detent surface 56 to release the engagement between the cam 53 and the load brake nut 30 to place the latter again in operation. To prevent a rapid backing away of the load brake nut, the ing 61 has been provided and engages with one of the screws 60 of the pawl bracket 59 in the event that a sudden and rapid acceleration was applied to the handle assembly.

A modified arrangement for accomplishing freewheeling of the hoist is shown in FIGURES 6 and 7, and reference is now made thereto. In general, this form of the invention features a disengageable pawl for the ratchet wheel functioning without the use of the earlier described hand wheel 13 and cam 53 to temporarily render the load brake ineffective so that the chain may be pulled through the hoist in either direction by hand. Specifically, in the form of FIGURES 6 and 7, the housing 101: is bored at 86a to receive a sleeve 44a housing a spring 43a resiliently urging a pawl 42a downwardly into contact with teeth 41a on the ratchet wheel 33a. During the raising operation, the spring 43a actuates when the pawl 42a is reciprocating over the ratchet wheel 33a, while during lowering the spring 43a forces the pawl into the ratchet wheel to prevent rotation of said wheel and thereby put the load brake in operation. Connecting with the pawl 42a is a control handle 79 of general right angular shape having a slot 80 adjacent one end thereof receiving a pin 81 carried by the pawl 42a. Bottoming at opposite ends on the sleeve 45a and control handle 79 is a spring 82 functioning to hold the handle 79 in a position of engagement or disengagement. Upwardly of the sleeve .5a the housing a is formed with a slotted opening 83 providing a handle engaging surface 84 for receiving the handle when the same is raised and rotated into a retracted position removing the pawl 42a from engagement with the sprocket wheel teeth 41a.

During a raising or lowering operation the control handle 79 is in a downward position disengaged from the housing surface 84. Accordingly, by means of negative rake on the ratchet wheel teeth 41a, the pawl oscillates vertically against said teeth during a raising operation, and said pawl 42a is pressed by the spring 43a into locking engagement with the teeth during a lowering operation to thereby put the load brake in operation. Movement of the load brake nut 30a and its cooperation with the friction discs 31a and 32a and the thrust disc 34a is essentially the same as earlier described in connection with the first embodiment of the invention.

To free wheel the hoist, however, the hand lever 51a is placed in a neutral position whereby the pawl 46a is out of engagement with the teeth 45a on the load brake nut 30a. The operating control handle 79 is thereupon raised and engaged with the housing surface 83 and the pawl 42a thereby removed from an engaging position with the ratchet wheel teeth 41a. By provision of negative rake on the ratchet wheel teeth, inadvertent manual disengagement of the pawl is prevented unless the operator deliberately raises the load slightly before lifting the control handle 79.

An important advantage of the pawl lift arrangement described is that foreign objects accidentally lodged between the pawl handle and the frame cannot cause failure of the pawl. To explain, the pawl lever 79 does not oscillate axially in its bore as the ratchet wheel 33a is rotating during either a raising or lowering operation. Although the pawl itself oscillates, the spring 82 is of sufiicient strength to hold the knob or handle 79 stationary against the engagement surface 83 on the frame body. Provision of the slot 80 in the handle 79 of a proper and predetermined length assures the freedom of movement required to accomplish this function. It may thereby be seen that the load brake cannot be rendered inoperative during either a raising or lowering operation should a foreign object become lodged between the handle and the frame since the handle is vertically stationary during oscillation of the pawl and said pawl will function as intended to engage the ratchet wheel teeth during raising or lowering to actuate the load brake nut and stop drive shaft rotation when the hand lever assembly 12:: is halted. As appears in the drawings, the hand lever 12a is a unitary assembly, and is secured to the shaft 23a by lock means 85.

It may be seen from the foregoing that applicant has provided a new and improved hoist construction formed of a one-piece main frame maintaining the shafts therewithin in correct alignment. The hoist is of minimum outline both vertically and horizontally, achieved by locating the sprocket shaft in vertical alignment with the drive or pinion shaft, and thereby the hoist is of greater utility in applications providing limited working space. Malfunctions of the hoist by reason of entrance of foreign objects into the operating mechanism are essentially remote, and free wheeling of the hoist is accomplished utilizing a minimum number of readily fabricated parts characterized by extreme reliability. By-provision of the novel bearing 24 and thrust washer and shield assembly 37, the shafts 16 and 23 and related parts may be located in the frame housing 10 prior to the positioning of said bearing 24'and thrust washer 37 in contact with the pinion shaft 23.

It is to be understood that the forms of the invention herein shown and described are to be taken as preferred shaft, a load brake including a ratchet wheel freely supported upon the load shaft, detent means connected to the driving member, means on said load shaft and rotatable therewith forming a detent receiving surface for bore in opposite directions in continuous engagement with the ratchet wheel during a raising or lowering or free-wheeling operation, a hand lever assembly for rotating the load shaft and moving the driving member axially away from the load brake to disengage the same, and a, lever reversal mechanism comprising a rotatable control member mounted on said lever assembly, resilient means arranged for expansion by said member, and 'a pawl supported by the lever assembly and rotatable upon movement of the control member clockwise or counter-clockwise into locking contact with the driving member to permit reversal of the lever assembly during raising or lowering of the hoist.

2. A hoist construction comprising, a relatively narrow body portion, a sprocket shaft and load shaft arranged in general vertical alignment within said body portion, bearing means entirely within said body portion supporting the shafts for rotation therein, one of said bearing means comprising a ring member formed with a flat face along the outer diameter received in a bore in the hoist body portion, a cover member secured to the body portion and shaped to prevent rotative movement of the ring member, a driving member mounted for rotation upon the load shaft, a load brake including aratchet wheel freely supported upon the load shaft, a pawl located within a' bore in the body portion and resiliently urged axially in said bore in opposite directions in'continuous engagement with the ratchet wheel 'dur-inga raising or lowering operation, means rotating the loadshaft and moving the driving member axially away from the load brake to disengage the same, said pawl lockably engaging the ratchet wheel when rotation of the load shaft has stopped and the load brake rendered effective, and stop means .on said load shaft and on said driving member to prevent a rapid backing away of the load brake when said means for rotating the load shaft is suddenly and rapidly accelerated.

3. A hoist construction comprising, a relatively narrow body portion provided with a chain receiving opening therein, pin means at one end of said, opening supported by the body portion, a chain anchor carried by the pin means, a sprocket shaft and load shaft supported in .general vertical alignment within the body portion and spaced upwardly from the chain anchor, a driving member mounted for rotation upon the load shaft, a load brake including a ratchet wheel freely supported .upon

the'loa d shaft, detent means connected to the driving a the driving member axially away from the load brake to disengage the same, said pawl lockably engaging the ratchet wheelwhen rotation of the load shaft has stopped and the load brake rendered effective.

4. In a hoist construction comprising a load shaft carrying a rotatable driving member effective to actuate a'load brake and prevent shaft rotation, the improve 8 ment which comprises a cam member supported by the shaft for rotation therewith and having a plurality of cam surfaces along its circumference, a radially extending lug between the cam surfaces preventing unrestrained rotation of said shaft, a resiliently urged detent element located for engagement with one of the cam surfaces, and a hand wheel carried by the shaft and connected to the cam member, the detent element moving radially inwardly into engagement with one of the cam surfaces upon a minor amount of shaft rotation by the hand wheel to operatively connect the cam member to the driving member and prevent actuation of the load brake during normal free wheeling of the hoist.

5. In a hoist construction comprising a load shaft carrying a'rotatable driving member efiective to actuate a load brake and prevent shaft rotation, the improvement which comprises a cam member supported by the shaft" for rotation therewith and having a plurality of cam surfaces along its circumference, said cam member being provided with a plurality of spaced key slots along its inner diameter permitting adjustment upon the shaft,-a' radially extending lug between the cam surfaces preventing unrestrained rotation thereof, and a resiliently urged rotatable ball element located for engagement with one of the cam surfaces, said element being pressed inwardly supporting a load shaft carrying a rotatable driving member effective to actuate a load brake and associated ratchet wheel on the shaft to prevent rotation thereof, the improvement which comprises a housing member supported by the frame, a pawl resiliently urged in an axial direction into 'engageable relation with the ratchet wheel, and

a control handle resiliently urged against'th e main f ame and connecting with the pawl and'essentially axially immovable during oscillation of the pawl whereby said pawl may move into engagement with the ratchet. wheel in the presence of a force restraining axial movement of the pawl control handle.

7. In a hoist construction comprising a main frame supporting a load shaft carrying a rotatable driving mem-' ber effective to actuate a load brake and associated ratchet wheel on the shaft to prevent rotation thereof, the improvement which comprises a housing member supported by the frame, a pawl axially movable within the housing member, spring means surrounding said pawl and maintaining said pawl in riding contact with the ratchet wheel, a control handle connecting with the pawl for raising the same during free wheeling of the hoist, and spring means maintaining the control handle against the main frame, said control handle being essentially axially immovable during oscillation of the, pawl whereby said pawl may move into engagement with the ratchet wheel in the presence of a force restraining axial movement of the pawl control handle.

, References Cited in the file of this patent UNITED STATES PATENTS 1,903,218

Knight Mar. 28, 1933 2,243,361 Stahl May 27, 1941 2,318,569 Camp et a1 May 4, 1943 2,687,196 Camp Aug. 24, 1954 2,736,408 Cofling Feb. 28, 1956 2,878,910

Gunkel Mar. 24, 1959

Images