US2596326A - Fabric belt hoist - Google Patents

Description

y 13, 1952 F. w. COFFING 2,596,326

FABRIC BELT HOIST Filed Nov. 27, 1950 BY M H Patented May 13, 1952 UNITED STATES PATENT OFFICE FABRIC BELT HOIST ration Application November 27, 1950, Serial No. 197,774

g 7 Claims. I

The present invention relates to improvements in pulling devices and primarily to pulling devices of the type adapted for use in hoisting and lowering loads. More particularly, the invention relates to that type of pulling device wherein the fabric belt is used as a hoisting and lowering medium.

It is one of the objects of the invention to provide a hoisting device wherein there is provided a drum over which a flexible, relatively inextensible hoisting belt is adapted to pass and be moved thereover by step by step movement imparted to the drum through the medium of a lever.

Another object of the invention is that of providing the brake means for normally holding the drum against rotation under load during the reciprocating release movement of the operating lever.

A further object of the invention is to provide means whereby during the lowering operation the drum is permitted to rotate under the weight of the load being restrained against excessive rotation by the operating lever and means of providing for during this lowering operation releasing the braking means which is normally operative under the weight of the load.

The full nature of the invention will be understood from the accompanying drawings and the following description and claims:

For the purpose of illustrating the invention an embodiment thereof is illustrated in the accompanying drawings in which Fig. 1 is a side elevation of a hoist embodying the invention with certain of the links of the structure removed for the purpose of clarity.

Fig. 2 is a similar view to Fig. 1 showing the operating lever at its lowermost hoisting position.

Fig. 3 is a similar view showing the operating lever in a position to reverse the holding means.

Fig. 4 is a sectional view on the line 44 of Fig. 3.

Fig. 5 is a sectional view on the line 5-5 of Fig. 3.

In the embodiment illustrated there is provided a hoisting drum H3 having its periphery corrugated to provide axially extending grooves II and over this drum there is adapted to pass a hoisting belt or tape I2 which is formed of fabric preferably of the type which is flexible and is relatively inextensible. It has been found that a belt woven of nylon provides a very satisfactory structure as it has extremely long wearing qualities and is extremely flexible while being practically inextensible.

This drum is rotatably mounted upon a 2 shaft [3 which is supported between a pair of side links it. Pivotally mounted on the shaft 15 extending between the upper ends of the side links M is a holding pawl which has somewhat the formation of a bell crank lever and is provided with a holding nose It adapted to engage in the grooves ll of the drum Ill. The outer end of this holding pawl is bifurcated to provide a pair of arms I? between which is mounted a block 58 swingably connected to the shank of a hook l9.

It is to be noted that due to the configuration of the holding pawl and the angular disposition of its shaft l5 with respect to a line passing vertically through the holding hook 19 the weight of the load will bias the nose [8 into the grooves ii of the drum H3 thereby frictionally locking the belt into the grooves and at the same time looking the drum against rotative movement.

For rotating the drum I8 I provide an operating handle or lever 20 pivoted on a shaft 2! extending between a pair of links 22, the lower ends of which are pivotally mounted on the shaft It. This lever is extended beyond the pivot point 2| to provide an engaging nose 23 which through the combined action of swinging the links 22 on the pivot 53 and swinging the lever 21] on the shaft M is adapted to be moved into the grooves ll of the drum Iii.

The arrangement is such that starting at the upward position on the lever as shown in Fig. 1 as the lever is pulled downwardly the nose 23 is forced into a groove of the drum and with a continued downward movement and with it the drum is rotated and with it the belt l2 so that a hoisting action is imparted to one side of the belt. As the lever is swung upwardly after having completed its downward lifting movement the nose 23 is somewhat released from the grooves H riding over the corrugations, but at the same time the nose it of the holding pawl is forced into one of the grooves thereby locking the belt or tape against reverse rotation and holding the belt or tape against movement.

The normal raising and lowering positions of the operating lever 28 is illustrated in Figs. 1 and 2. For lowering the load it is necessary to release and hold in its released position the holding pawl including its engaging nose It and rely on the holding efiect of the lever nose 23 in'the grooves of the drum Ill, the lever engaging the grooves at its lowermost position and gripping the same to hold the fabric belt from slipping and to restrain the same from slipping backwards and the drum from undue rotation as the lever is moved upwardly.

To this end I provide a pair of releasing and holding links 26 which are so disposed that during the hoisting movement of the lever 20 the holding pawl will be normally operative but when the lever '20 is moved beyond a predetermined lowermost position these links are thrown into a position to move and hold the holding pawl out of eifective wposition. .For operating these links there isiprov ided onopposite sidesa pair of operating plates 2'! which are oscillatingly mounted on the shaft I3. One of the ends of the links 26' is pivotally connected as at 28 to this plate andthe opposite ends of the links are pivotally=connected as at 29 to the lower end, or noseend, ofathe holding pawl. The angle of these links is such that when the plate 21' is locked to its uppermost position the links will be ineffective to hold the pawl member out of operative position.

To permit the normal oscillation of-the'lever 20 for elevating the loa'dor rotating th drum Iii in clockwise direction, these plates at their outer ends are slotted as at 30 to receive side pins 3! on the links 22 connected to the lever 23. During normal raising operation this pin oscil- -lates in the slot 38 from the position illustrated in Fig. l to the position illustrated in liig. 2 and durrotate .th drum i iiin a counter-01ockwise-direc- -tion under the control of the lever gdthe lever is "moved to its extreme downward position, the ,}30Sll7l011 illustrated i n Fig. 3,-and' as the leveris mo-vedj past thepredetermined lowermost I point indicated at Figt-"thepins ti willengage Jthe hbO-ttOlTirBlldS of the 'slotsSiJ rocking'the plates'in r a clockwise direction on'the shaft l3 and thereby .moving the lower fend: of the 'linksiit to a cam- ;ming position, or the position illustrated in Fig.3,

wherein the links are moving practically past dead center'and maintain the holding pawl in its releasedposition. At the same time, however,

*the nose of theleverrzii engages the drum holding the drumagain'st rotationexcept as the operator ;permits the lever to move upwardly.

=-As th lever moves upwardly to "the limit' of its movement as ShOWnl in'Fig l, the pins=3l will 'engagecthe' to wall ofthe' slot iii rocking the plates l'zl in' an opposite direction to move the links into'neutral position.

n the next downward stroke of the leven'and 'due to its pivotal connectionat 2 I' this downward 'strokemay'be taken without engaging the same with th drum. with the lever: moving to its extreme downward position 'and then swing 'into en- .ggagem'ent with the szdrum. Another controlled -'clockwise movement'of the-drum may bepermittedtunderlthe weight oflthe' load.

l'Ihe inventionclaimed is: *lflln a pulling device in combination :a pefiiphera'lly: corrugated rotatable drum, a, shaft for said drum, a I pair of .links between which i said ehaftfis fmounted, a supporting -holding "pawl piv'otally supported'between said links and havdug-a holding nose bi-ase'd into brakin T engagement -with the 'corrugations of said drum by the weight of the load, a relativelyinextensible flex- Lible' hoisting belt'carried' by said drum, a, pair of links pivoted on said drum shaft, an operating lever pivotally mounted between said links having a nose engageable with the corrugations of said drum and effecting a rotation of said drum in a hoisting direction by the downward rocking of said lever to a predetermined point, and

means operating by a downwardimovement of saidllever beyond said predetermined: point for ineffective,- said: means being movable out :of its iixed'holdingposition by the rocking of .thezlever upwardly beyondsaid predetermined point.

maintaining said pawl holding means ineffective during the oscillation of said lever below said predetermined point.

2."In= a pulling device in combination a peripherally corrugated rotatable drum, a shaft for said drum, =a ipairzofzlinks between which said shaft is mounted, :a-Lsupporting holding pawl pivotally supported between said links and having an en- "g'aging'nose'biased into holding engagement with the corrugations of said drum by the weight of the load, a relatively jinextensible flexible hoisting belt carried by said drum, apair otrlinks 'drum and effecting a rotation of, said drum in a hoisting direction by the downward .rooking'j-of said level-to a predetermined pointand'means operating by a downward movement of said lever beyond said predetermined point.for" maintaining said pawl holding meansineffectiveldur'ing the oscillation of said lever below said predetermined point, saidmeans being operable to render said holding means-effective when the leveris moved above said predetermined point.

3. Ina pulling device incombination mentherally; corrugated rotatable drum-,la. shaft iforisaid drum, a'pair of links between-whichsaidshaft is mounted, a supporting holding pawl: pivotally supported between said links and having aholding. nose biased into holding i engagement :With

thecorrugationsof said drum by theweiighttof the load, a relatively.inextensible.fiexibleehoisting belt carried by said drum,-a pairoflinks pivoted on said'drum shaft; an operatinglever pivotally mounted between-saidjlinks. having a nose engageable with the corrugations'of said drum and effecting a. rotation of-said-dr um in-a hoisting direction-by the downward rocking of.

erally corrugated rotatable drum, a shaft for-said drum, a pair of links between .which-said-shaft mountedyasupporting holding pawl'pivotally 'supported'betwe'en said links and having aholding nose biasing into holding'engagement with the corrugations-of said drum :by-the weight .of

the load,'a relatively inextensible flexibleh'oisting belt'carried by said drum, a pair of links pivoted on 'said'drum shaft,- an operating lever pivotally mounted between said links having 'a nose-'engageable with'the pockets-0f said-drum and'effecting arotation of said drum in a' hoisting direction by the downward rocking ofisa-id lever to :a predetermined point, and means operated by the downward movement ofsaid lever beyond a predetermined point andmovable-into a fixed position for render-ing*saidholdingpawl 5. In a pulling device in combinatiomla'pe'ripherally corrugated rotatable drum, a'shaft for said drum, a pair of links between which said shaft is mounted, a supporting pawl supported between said links and having a holding nose biased into braking engagement with the corrugations of said drum by the weight of a load, a flexible relatively inextensible hoisting belt carried by said drum, a pair of links pivoted on said drum shaft, an operating lever pivotally mounted by the said links having a nose engageable with the pockets of said drum and effecting a rotation of said drum in a hoisting direction by the downward rocking of said lever, rocking plates mounted on said drum shaft, means operated by the rockin of said plates in one direction for moving and holding said holding pawl in disengaged position and means operated by said lever for operating said rocking plates.

6. In a pulling device in combination, a peripherally corrugated rotatable drum, a shaft for said drum, a pair of links between which said shaft is mounted, a supporting pawl pivotally supported by the said links and having a holding nose biased into braking engagement with the corrugations of said drum by the weight of the load, a flexible relatively inextensible hoisting belt carried by said drum, a pair of links pivotally mounted on said drum shaft and an operating lever pivotally mounted between said links having an engaging nose movable into engagement with the pockets of said drum, operating links connected to the holding nose of said holding pawl and movable in one direction for moving said holding nose out of engaging position relatively to the corrugations of said drum, rocking plates for swinging said links into operative position operated by said lever and a lost motion connection between said lever and said rocking plates.

7. In a pulling device in combination, a peripherally corrugated rotatable drum, a shaft for said drum, a pair of links between which said shaft is mounted, a supporting holding pawl pivotally supported by the said links and having a holding nose biased into holding engagement with the corrugations of said drum by the weight of a load, a flexible relatively inextensible hoisting belt carried by said drum, a pair of links pivotally connected to said hoisting drum shaft and an operating lever pivotally connected between the ends of said links and having a nose swingable into and out of engagement with the corrugations of said drum, rocking plates mounted on said drum shaft, operating links extending between said rocking plates and the nose of said holding pawl, and means carried by said lever having a lost motion connection with said rocking plates for rocking the plates in one direction to move the links past dead center to raise the holding nose out of engagement with said drum and maintaining the same in said position and movable in an opposite direction to move one end of the links past dead center to release said holding drum.

FREDRICK W. COFFING.

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

UNITED STATES PATENTS Number Name Date 328,023 Glashan Oct. 13, 1885 1,100,956 Davies et a1 June 23, 1914

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