US1862331A

US1862331A - Automatic reverse ratcheting hoist

Info

Publication number: US1862331A
Application number: US389956A
Authority: US
Inventors: Fredrick W Coffing
Original assignee: Individual
Current assignee: Individual
Priority date: 1929-09-03
Filing date: 1929-09-03
Publication date: 1932-06-07
Anticipated expiration: 1949-06-07

Description

June 7, 1932.

F. W. COFFLNG AUTOMATIC REVERSE RATCHETING HOIST Filed Sept. 3, 1929 2 Sheets-Sheet l INVENTOR. F/tzf'DR/CK m Cor-nus.

A TTORNEYS.

June 7, 1932. F. w COFFING AUTOMATIC REVERSE RATCHETING HOIST Filed Sept. 5, 1929 2 Sheets-Sheet INVENTOR. FkflJ/il [K (OFF/N6,

A TTORNEYJ- Patented June 7, 1932 UNITED STATES FREDRICK W. GOFFING, OF PERRYSVILLE, INDIANA AUTOMATIC REVERSE v RATCHETING HOIST Application filed September 3, 1929. Serial No. 389,956.

sociated with a load supporting chain and the actuating and locking means for said sprocket which permits the chain to advance or retire step by step, or permits the free movement of the chain for a quick and approximate positioning when there is but little or no weight on the chain.

Another feature'of the invention consists go in the automatic step by step load lowering movement of the hoist if the load is not excessive and the hoist is conditioned for reversing or lowering movement.

A third feature of the invention consists in providing parts of the mechanism in duplicate such that the actuating handle or lever may be positioned at either side and function satisfactorily, said lever for safety purposes being prevented from complete rotation by a suitable stop. A fourth feature of the invention consists in an improved stop for the chain and the method of making and mounting same.

The full nature of the invention will be 36 understood from the accompanying drawings and the following description and claims:

In the drawings Fig. 1 is an elevational view of the sprocket, chain and half of the housing included in the hoist. Fig. 2 is an elevational view of the locking or control portion of the hoist with the actuating lever and associated mechanism removed. Fig. 3 is an elevational view similar to Fig. 1 showing the main locking pawl in neutral or free chain position. Fig. 4 is a view similar to gential to the sprocket so that the load is Fig. 2 but with the parts in another position. Fig. 5 is a sectional view of the hoist taken on line 55 of Fig. 1 and in the direction of the arrows. Fig. 6 is an elevational view of the rear of the lever handle and lever supported mechanism. Fig. 7 is a transverse section thru the stop and end link of the chain. Fig. 8 is a plan View of the stork in the process of forming the stop.

Fig. 9 is a perspective View of the eccentric shaft.

Fig. 10 is a sectional View taken on line 1010 of Fig. 5, with parts shown in ele-' vation, to show pin 59 of the pawl 31 engaging the surface of one cam pawl 54., and associated parts.

In the drawings 10 indicates the bodyportion of the hoist which is formed of two substantially similar but complementary, preferably malleable iron, half portions, secured together as by riveting or the like. The housing or body portion thus formed includes two inclined channels 11 and 12 which simultaneously communicate with each other and chamber 13. Pivotally mounted in the bearings 14 and 15 in the housing is a spindle 16 which extends through the body housing and mounts in chamber 13 an integral sprocket gear 17, the teeth of which project into the channels at the meeting location and mesh with the links 18 of the load supporting chain. positioned in said channels.

A stop 19 at one end of the chain prevents complete withdrawal of the chain through the hoist by preventing a sprocket tooth from seating in the link space occupied by the stop. The other end of the chain is provided with a suitable load supporting link, hook or the like. The housing 10 swivelably supports at 21 a similar anchoring hook 2O opposite therefrom.

The channel 12 and swivel axis of hook 20 are in longitudinal alignment and are tantaken by the sprocket as a tangential load and is in line with the two hooks.

In chamber 13 there is pivotally mounted a locking pawl 23. Shaft 22 which supports said pawl extends through the body wall 10 and projects into the lever handle housing 7. The pawl 23 is maintained in looking position to prevent lowering of the weight and the chain by a multiple spring including a coiled spring 24 having one end connected to the pawl and its other end connected to a flat spring 25 which in turn has its other end socured to the frame 10 by rivet 125. The load is elevated by the clock-wise rotation, reference being had to Figs. 1 and 3 of sprocket pinion 17 through the lever handle 29, hereinafter to be described, which raises the chain 18 and elevates the load. In this movement the pawl 23 automatically ratchets over and seats itself behind each successively presented sprocket tooth to prevent reverse movement of the sprocket while the actuating portion including the lever handle is being reversed for further rotation.

The mounting of the lever handle 29 is shown particularly in Fig. -.5 and the lever handle itself is shown in Fig. 6. The spindle 16 in addition to being provided with a sprocket gear includes an integral ground cylindrical portion 27 having ratchet teeth 28 cut therein, the cylindrical portion being rotatably supported in the bearing 15. A smaller cylindrical portion 9 is receivable by a cylindrical portion 8 of the housing portion 7 of the handle which is provided with the elongated extension or handle portion 29.

A washer 66 and a'bolt 67 are mounted by threading the latter into the threaded portion of chamber 68, the latter having an outlet 168 for lubrication, which is supplied thereto by removing the bolt 67 filling chamber 68 with cup grease and replacing bolt 67.

Pivotally supported at 30 on the handle is a pawl 31 which mounts a pin 59 that is an actuating member and also serves as a stop or anchorage for a spring 32. The other end of the spring engaging a wall portion 7 of the handle, and the spring 32 is coiled about the pivot 30. The pawl 31 includes an angular flat spring extension 34 which is apertured as at 36 to receive the off-set end of a rod 35. Rod 35 is reciprocated by a finger lever 37 pivotally supported adjacent the end of the handle lever in the ears 40. Lever 37 includes an arm 39 which is associated with the angular end 38 of the rod so that when the member 37 is depressed toward the handle, the rod 35 will be projected toward bearing 8, whereupon the off-set portion at the end of the rod 35 adjacent the spring aperture 36 will bend the spring before tilting occurs of the pawl 31 counter-clockwise or radially outward from the ratchet teeth 28, provided there is load upon said pawl. Therefore this arrangement prevents dropping of load so that the handle control is fool-proof. If no load is on the ratchet, then pawl 31 is relieved from it by the actuation of rod 35 since spring 34 is slightly stronger than spring 32. It is to be remembered, however, that movement of the pawl 31 also moves theactuating pin 59 and reference thereto will be made later.

By referring to Figs. 2 and 4 it will be noted that the top plate 48 includes an abutment, face or ledge 56 and substantially opposite therefrom there is pivotally supported (by the so-called reversing ring construction) as at 52 a cam pawl having the camming portion 54 and the rear face 50, said pawl being normally projected outwardly, that is with its face 50 extended beyond the plate as shown in Fig. 4 and by means of the fiat spring 49. The pin 59 carried by the handle pawl 31, see Fig. 6, is adapted to either engage the flat face 50 of the pawl, or

the face 56 of ring 48 for clockwise movement of the reversing. ring construction, reference being had to Figs. 2 and 4, which is counterclockwise rotation with reference to Figs. 1

and 3.

the sprocket and the load is carried by the,

handle through the ratchet and is elevated in the rotation of the ratchet and sprocket by the chain.

The handle as shown in Fig. 6 is provided with an opening 100 so that it may be hung upon a linemans belt and the like since this puller-hoist weighs in the neighborhood of from 12 to 25 pounds. The opening 100, Fig. 6, also may receive a wire or rope for actuating the handle at a distance, i. e." from the cross arm to the ground. The handle may be positioned for oscillating movement upon either side of the longitudinal plane through the chain and hooks. The handle will operate just as effectively when positioned upon either side. Stop 33 tion of the handle.

The locking pawl shaft 22 extends into the handle chamber and supports an angularly extending arm 26, see Figs. 2 and 4, which has associated therewith a spring 47, the other end of which is secured to the reversing ring construction as at 46, see Figs. 2 and 4. Upon the opposite side of the housing from that mounting the handle there projects a shaft 101 and carried thereby is a finger prevents complete rotais maintained in that position by the flat spring 25 hearing against the

fiat face

63 or 65 thereof. In this construction spring 25 therefore has an additional function. The portion of the rock shaft 101 which is extended into the chamber formed by the handle has an eccentric pin having a flatface 142 and an arcuate periphery 42 completing the same, and the aforesaid is operatively associated with the reversing ring construction as hereinafter set forth.

The shoulder 114 on shaft 16 adjacent bearing. 14 prevents shaft movement toward that hearing. The flange 115 adjacent hearing 15 prevents movement in the opposite direction. The elongated spindle portion 9 prevents cooking of the handle 29 since the same is provided with the elongated bearing 8 cooperating therewith.

Reversing ring construction In addition to the features of construction specifically pointed out hereinbefore, the

present invention includes a so-called reversing ring construction which embodies the chief features of the invention.

The outer plate 48 of said construction is secured in spaced relation to the inner plate 148, see Fig. 5, and said plates are of general ring outline. The ring construction is looked upon the elongated sleeve portion 15 by the split locking ring 62 seatable in the groove 116 in said sleeve bearing.

Plate 48 includes a projecting tooth 56 having an inclined face 156. Opposite therefrom and pivotally supported at 52 between

plates

48 and 148 is a so-called shedding pawl having the substantially radial face 51 and the cam point 54. A flat spring 49 normally projects the face 51 beyond the periphery Of plate 48, see Fig. 4. Suitably mounted upon the housing is a stationary stop and cam 55 4 that also serves as an anchorage for spring 45.

"When the ring construction is rotated clockwise, see Fig. 4, the point 54 of the pawl rides upon the cam 55 and the radial face 51 is retracted behind the periphery of plate 48 and this is in opposition to spring 49.

The inner plate 148 has a notch formed therein, one edge of which, adjacent the cam pawl 54, includes an edge 248 that may engage the stop and combination cam 55 when clockwise movement of the ring is sufiicient in that direction.

The opposite edge of the notch thus formed is indicated at 348 and is engageable by the eccentric pin carried by shaft 101 and having an arcuate face 42 anda flat face 142, see Figs. 2 and 4. Shaft 101 also has the two fiat cam faces 63 and 65, see Figs.

1 and 3. Shaft .101 is oscillatableiby the handle or finger piece 44, see Figs. 1 and 3. When face 42 of the pin carried by the shaft 101 engages edge 348 the reverse ring is retarded clockwise, compare Figs. 2 and 4, which transforms the device into the customary unidirectional ratcheting tool, see Fig. 2.

The two

plates

48 and 148 also support a pin 41, the same being positioned almost diametrically "opposite pivot 52 and upon which the shedding pawl is mounted. The

lateral arm 26 carried by the shaft 22 (in turn carrying the locking pawl 23) engages the pin 41. Rotation of shaft 101 by lever or finger piece 44 positions the reversing ring in advanced position, as shown in Fig. 4, or in retarded position, as shown in Fig. 2 depending upon the direction of rotation. Both springs 45 tend to rotate the ring construction into advanced position. Spring 47 assists such tendency. The spring 24 opposes

springs

45 and 47. All of the aforesaid springs are .operatively connected through the shaft 22 and arm 26. Spring 47 is so arranged and mounted that until required for operation it may be considered as entirely inoperative for the tension is imparted to it when required by rotation of the/reverse ring through the eccentric pin 42 or the pin 59 in the pawl 31.

Springs

47 and 24 are both effective in the same direction so far as their efiect on pawl 23 and arm 26 is concerned.

The face 56 of the plate 48 and the face 50 of the pawl 51 are diametrically positioned and either may be engaged by the pin member 59 carried by the lever supported pawl "31, see Fig. 6. Thus the handle in normal operation may be positioned upon either side of the stop 33 upon the housing and satisfactorily operate at either'side and without complete rotation of the handle so that complete swinging of the handle cannot take place.

Operation In the rotation of the lever handle 29 to I elevate the load the cam face 65 must engage spring 25. The load sustaining pawl 23 oscillates into and out of tooth locking position while the load is carried by the spindle" and by the handle through the pawl 31 engaging in the ratchet teeth 28. Upon reverse handle movement spring 24 causes the 1 In reversing to lower the load cam face 63 of shaft 101 bears on the flat spring 25 which advances cam 42, see Fig. 4, and releases tension on springs45.

. For reversal of the chain through the hoist when there is no load thereon, the lever 44 is turned so that cam 63 engages flat spring 1 25, see Fig. 3. This moves the eccentric cam pin 42-142 into position so that the reverse ring construction is advanced anti-clockwise by

springs

45 and 47 which forces the cam pin 41 to tilt the arm 26. This tilting lifts the pawl 23 out of pinion tooth engagement. W hen latch 37 on handle 29 is depressed, pawl 31 will be disengaged from ratchet 28. The chain may then be pulled into the lowered position. The chain with no load upon it also may be freely pulled through the device to shorten the effective chain length so that so-called free chain movement in both directions is thus possible.

Tf there is any material tension or load on the chain the draft in sprocket tooth 17, see Fig. 1, will not permit locking pawl 23 to release or tilt from looking position without first advancing the sprocket 17 clockwise, see Fig. 1, sufficient for the pawl 23 to pass out of the tooth pocket. lVhen there is a load on the chain and it is desired to lower the load, lever 44 islturned to position the cam face 63 against spring 25 which advances cam 42, see Fig. 4.

Whenever lever 44 is turned up, see Fig. 1, the reverse ring is retarded into so-called neutral position Whenever the lever 44 is turned down, see Fig. 3, the pin.42142 is neutral and the reverse ring is effective for reversal.

The hand lever 29 is turned anti-clockwise until the load is taken thereby which thereupon permits springs 45 and 47 to advance the reverse ring and cam pin 41 to engage arm 26 and thus tilt pawl 23 out of locking and load sustaining position. Reverse movement of lever 29 causes pin 59, see Fig. 6, to

engage face 56 of plate 48 or the shedding pawl face 50 and causes reverse ring movement. When this occurs cam pin 41 is released from engagementwith the arm 26 and spring 47, carried by the ring, and spring 24 tilts arm 26 and pulls locking pawl 23 into tooth locking position to take the load. Thereupon the handle supported driving pawl 31 may be released from ratchet 28. Springs 45 and spring 47 pull face 56 or face 50 of the shedding pawl 51 against the actuating'pin 59 depending upon which side of the hoist the handle 29 is positioned.

This spring movement of the ring lifts pawl 31 from ratchet 28 sufficient to just clear the ratchet tooth. Lowering of the lever handlecounter clockwise permits pin 59 to leave plate face 56 or pawl face 50, and spring 32 seats the pawl 31 in the next adjacent ratchet tooth 28. By this movement only one ratchet tooth distance advance is possible in lowering under load, and so-called dropping of the load is prevented. Movement of the reverse ring by engagement of either plate face 56 on shedding pawl 51 causes the aecaeaa shedding pawl portion 54 to engage the face of abutment 55 carried by the housing. The action in either event subsequent there to is the same as previously set forth.

The operation of the device for convenience has been described as for raising and lowering but applies as well to pulling and slacking off purposes and the terminology in the claims is to be thus interpreted.

In Figs. 5, 7 and 8 an improved chain stop is illustrated. Herein the same includes a stop block 80 having a semicircular recess 81 in one end and of a large diameter and a similar but smaller recess 82 at the opposite end. These stops, see Fig. 8 are formed from bar stock, with alternate holes of different diameters formed therein and thence severed transversely through the holes as shown;

The holes may be formed by drilling or punching. The severance may be by sawing or shearing. v

The larger recess 81 embraces the pintle supported spacer or roller 83 while the smaller recess 82 embraces the pintle 84. The links are indicated at 85. The end link includes a standard detaching locking arrangement called a master link instead of having its pintles upset as indicated on the drawings for the other links. The end pintles are suitably fashioned to detachably receive the yielding locking member 86 which may be forcibly removed therefrom.

The aforesaid construction permits standard lengths of chain to'be connected in the usual manner and the stop member 82 removed and replaced in the endmost link of the connected chain lengths.

The invention claimed is:

1. In a free chain hoist the combination of a load sustaining sprocket, a spindle sup' porting the same, a body supporting said spindle and including a chain passage into which said sprocket projects, a sprocket chain in said passage and engageable by the teeth of the sprocket, a load sustaining pawl pivotally supported by the body and normally preventing return rotation of the sprocket, an operating lever handle, a ratchet engaging pawl supported by said handle and movable therewith, a ratchet secured to said spindle for rotating the same and said sprocket through said second mentioned pawl for moving the chain in one direction, said chain being free running in said direction, and means co-acting with the ratchet engageable pawl and the sprocket engageable pawl for automatically releasing the same for step by step reverse movement of the chain.

2. In a free chain hoist the combination of a load sustainin sprocket, a spindle supporting the same, a body supporting said spindle and including a chain passage into which said sprocket projects, a sprocket chain in said passage and engageable by the teeth of the.

sprocket, a load sustaining p awl pivo'tally ating lever supported by the body and normally preventing return rotation of the sprocket, an operhandle, a ratchet engaging pawl supported by said handle and movable therewith, a ratchet secured to said spindle for rotating the same and said sprocket through said second mentioned pawl for moving the chain in one direction, said chain being free running in said direction, and means co-acting with the ratchet engageable pawl and the sprocket engageable pawl for automatically ating lever handle, a ratchet engaging pawl releasing the same for step by step reverse movement ofthe chain, said means being arranged for automatic actuation by the weight of the handle when not more than a predetermined weight including the weight of the chain is supported by the sprocket.

3. In a free chain hoist the combination of a load sustaining sprocket, a spindle supporting the same, a body supporting said spindle and including a chain passage into which said sprocket projects, a sprocket chain in said passage and engageable by the teeth of the sprocket, a load sustaining pawl pivotally supported by the body and normally preventing return rotation of the sprocket, an opersupportedcby said handle and movable therewith, a ratchet secured to said spindle for rotating the same and said sprocket through said second mentioned pawl for moving the chain in one direction, said chain being free running in said direction, means co-a-cting with the ratchet engageable pawl and the sprocket engageable pawl for automatically releasing the same for step by step reverse movement of the chain, and means carried by the body preventing complete rotation of the lever handle.

4. In a free chain hoist thecombination of a load sustaining sprocket, a spindle supporting the same, a body supporting said spindle and including a chain passage into which said sprocket projects, a sprocket chain in said passage and engageable by the teeth of the sprocket, a load sustaining pawl pivotally supported by the body and normally preventing return rotation of the sprocket, an operating lever handle, a ratchet engaging pawl supported by said handle and movable therewith, a ratchet secured to said spindle for rotating the same and said sprocket through said second mentioned pawl for moving the chain in one direction, said chain being free running in said direction, means alternately co-acting with the ratchet engageable pawl and the sprocket engageable pawl for automatically releasing the same for step by step reverse movement of the chain, and means carried by the body preventing complete rotation of the lever handle, said alternately co-acting means being arranged for opposite positioning of the handle and permitting oscillation thereof through an arc of less than 180 degrees.

5. In a free chain hoist the combination of a load sustaining sprocket, a spindle supporting the same, a body supporting said spindle and including a chain passage into which said sprocket projects, a sprocket chainin said passage and engageablc by the teeth of thesprocket, a load sustaining pawl pivotally supported by the body and normallypreventing return rotation of the sprocket. an operating lever handle, a ratchet engaging pawl supported by said handle and movable therewith, a ratchet secured to said spindle for rotating the same and said sprocket through said second mentioned pawl for moving the chain in one direction, said chain being free running in said direction, and means co-acting with the ratchet engageable pawl and the sprocket engageable pawl for automatically releasing the same for step by step reverse movement of the chain. said co-acting means associated with the ratchet engageable pawl and the sprocket enga geable p'awl being arranged for positioning for maintaining both in non-operative position when there is no load on the chain for free running of the chain in the reverse direction.

6. In a free chain hoist the combination of a sprocket, a spindle supporting the same, a

body supporting said spindle and including in one direction, means associated with the load sustaining pawl for permitting free runmng of the chain in this direction, means coacting with the ratchet engaging pawl and the sprocket engaging pawl for automatically releasing the same for step bystep reverse movement of the chain, and means cooperating with the sprocket engageable pawl for normally maintaining the same in nonsprocket engaging position for permitting free running of the chain in the reverse direction, said means upon the application of a predetermined load being arranged to automatically lock the chain against free running in said reverse direction.

I 7. In a chain hoist the combination of a rotatably supported spindle, a sprocket rigid therewith, a ratchet also rigid therewith, an actuating pawl engaging said ratchet, a load sustaining pawl engaging said sprocket, a ring having limited rotary movement relative to the spindle, and means associated with the ring and cooperating with the ratchet engageable pawl to permit predetermined operation of the sprocket.

'8. In a chain hoist the combination of a rotatably supported spindle, a sprocket rigid therewith, a ratchet also rigid therewith, an actuating pawl associated with said ratchet, a load sustaining pawl associated with said sprocket, a ring having limited rotary movementrelative to the spindle, a locking arrangement for said ring, and means associated with the ring co-acting with said pawls for automatically disengaging the ring from locking engagement and permitting predetermined reversal of the sprocket.

9. In a chain hoist the combination of a ro tatably supported spindle, a sprocket rigid therewith, a ratchet also rigid therewith, an actuating pawl associated with said ratchet, a load sustaining pawl associated with said sprocket, a ring having limited rotary movement relative to the spindle, a locking arrangement for said ring, means associated with the ring co-acting with said pawls for automatically disengaging the ring from locking engagement and permitting predetermined reversal of the sprocket, and other means associated with said ring for intermittently actuating the same and returning the ring to initial position for subsequent operation and insuring step by step reverse movement of the sprocket.

10. In a chain hoist the combination of a housing having a support at one end and a chain channel at the opposite end and in substantial alignment with the axis of the support, said housing having an angularly directed extension channel communicating with the inner end of the first mentioned ch annel. a chain positionable in said channels, a sprocket chamber in said housing, a sprocket in' the chamber, said sprocket being mounted such that the teeth thereof have engagement with said chain at the meeting of the channels whereby a tooth in each channel is in chain engagement and at least two teeth of the sprocket are always in chain engagement.

11. In a chain hoist the combination of a housing having a support at one end and a chain channel at the opposite end and in substantial alignment with the axis of the support, said housing having an angularly directed extension channel communicating with the inner end of the first mentioned channel, a chain positionable in said channels, a sprocket chamber in said housing; a sprocket in the chamber, said sprocket being mounted such that the teeth thereof have engagement with said. chain at the meeting of the channels whereby a tooth in each channel is in chain engagement and at least two teeth of the sprocket are always in chain engagement, a load sustaining pawl operatively associated with said sprocket, and means normally constraining said pawl toward sprocket engagement, said pawl having a predetermined draft for the purpose described.

12. In a chain hoist the combination of a housing having a support. at one end and a chain channel at the opposite end and in substantial alignment. with the axis of the support, said housing having an angularly directed extension channel communicating with the inner end of the first mentioned channel, a chain positionable in said channels, a sprocket chamber in said housing, a sprocket in the chamber, said sprocket belng mounted such that the teeth thereof have engagement with said chain at the meeting of the channels whereby a tooth in each channel is in chain engagement, a load sustaining pawl operatively associated with said sprocket, means normally constraining said pawl toward sprocket engagement, said constraining means including a coil spring arcuately associated with said pawl and a flat spring connected thereto, and a control member engageable by said flat spring and normally retained in predetermined position thereby but permitting forcible movement therefrom.

13. In a chain hoist the combination of a housing having a support at one end and a chain channel at the opposite end and in sub stantial alignment with'the axis of the support, said housing having an angularly directed extension channel communicating with the inner end of the first mentioned channel, a chain positionable in said channels, a sprocket chamber in said housing, a sprocket in the chamber, said sprocket bemg mounted such that the teeth thereof have engagement with said chain at the meeting of the channels whereby a tooth in each channel is in chain engagement, a load sustaining pawl operatively associated with said sprocket,

means normally constraining said pawl toward sprocket engagement, said constraining means including a coil spring arcuately associated with said pawl and a flat spring connected thereto, a control member engageable by said fiat spring and normally retained in predetermined position thereby but permitting forcible movement therefrom, and a lever associated with said last mentioned member, the same having a plurality of flat faces each for selective engagement with said flat spring.

.14. In a free chain hoist the combination with a load sustaining sprocket, a load sustaining pawl operatively associated therewith, a sprocket actuating ratchet, a ratchet engaging pawl, a handle mounting said ratchet engaging pawl, of a reverse ring construction including spring means normally constraining the ring toward one position, an eccentric member for permitting ring positioning in either of two positions depending upon the positioning of said member, an arm associated with the load sustaining awl, and an actuating member associated wit the ratchet actuating pawl for predetermined ring movement and pawl control.

15. In a free chain hoist the combination with a load sustaining sprocket, a load sustaining pawl operatively associated therewith, a sprocket actuating ratchet, a ratchet engaging pawl, and a handle mounting said ratchet engaging pawl, of a reverse ring construction including a radial projection op-. eratively associated with said ratchet engageable pawl for ring movement therewith, means pivotally mounting said ring construction, and a cam engageable by the ring construction in the rotation of the ring for predetermined movement thereof.

In witness whereof, I have hereunto affixed my signature.

FREDRICK Wu COFFING.