US3848827A

US3848827A - Magnetic rotary locking and release mechanism

Info

Publication number: US3848827A
Application number: US00402993A
Authority: US
Inventors: B Tamarin
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-10-03
Filing date: 1973-10-03
Publication date: 1974-11-19
Anticipated expiration: 1991-11-19

Abstract

The pawl of a ratchet gear and pawl mechanism is biased magnetically toward the gear, which is partially desegmented to permit reversal of the pawl between positions of engagement with the segmented portion of the gear and of sliding disengagement therewith. The resulting magnetic locking and release mechanism is exemplified in a cord reel spring-biased to retract the cord and wherein the pawl comes into locking engagement with the gear upon unwinding of the cord and into released disengagement therewith upon rewinding of the cord.

Description

United States Patent [191 Tamarin Nov. 19, 1974 MAGNETIC ROTARY LOCKING AND 3,715,526 2 1973 Blanch 242/l07.6

RELEASE MECHANISM Primary Examiner-John W. Huckert' [76] lnvemor' gggzg k gf "r3 21 Assistant Examiner-Edward J. McCarthy Pennsylvania A Philadelphia Pa Attorney, Agent, or Firm-Charles A. McClure [22] Filed: Oct. 3, 1973 57 ABSTRACT PP 402,993 The pawl of a ratchet gear and pawl mechanism is biased magnetically toward the gear, which is partially [52 US. Cl. 242/107.7 desegmemed Permit reversal the pawl 51 Int. Cl. B65b 75/48 psitins engagement with the Segmented Pmtio" [58] Field of 242/100 1001 107 R of the gear and of sliding disengagement therewith. 4 6 10737 The resulting magnetic locking and release mechanism is exemplified in a cord reel spring-biased to retract [56] References Cited the cord and wherein the pawl comes into locking engagement with the gear upon unwinding of the cord UNITED STATES PATENTS and into released disengagement therewith upon re- 3,450,369 6/1969 Blanch 242/l07.7 i di f h d 3,528,624 9/l970 Tamarin.... 3,596,849 8/197l Tamarin 242/ 107.7 12 Claims, 8 Drawing Figures SHEEI 1 OF 3 PATENTEL HEY I 9 I974 MAGNETIC ROTARY LOCKING AND RELEASE MECHANISM This invention relates to locking and release mechanism having a ratchet componet such as is useful in a cord reel or similar rotary device.

Cord reels having electrical or non-electrical cords extensible therefrom and retractable thereonto often have ratchet mechanism for facilitating use of the cord at nearly any intermediate length between fully unwound and fully wound. Such reel has a rotary sheave mounted in a non-rotating body or support, and the ratchet gear and pawl are supported separately by those two components so that rotation relative to one another occurs upon rotation of the sheave. If the pawl is pivoted upon the fixed frame or support it may be biased into engagement with the gear either by gravity (from a superior position) or by a spring (from any position), and a spring has been the conventional biasing means when-as is more common-the gear is affixed to the fixed body or frame and the pawl is pivoted on the rotating sheave.

My U.S. Pat. No. 3,596,849 discloses a ratchet gear and pawl type of locking and release mechanism for a cord reel in which the pawl is biased magnetically into engagement with the gear. While very effective in holding the cord at any desired extended length, that construction is not adapted to slow retraction of the cord. Instead, the cord must be allowed to wind up rapidly upon the sheave, or the pawl will re-engage and halt the retraction. Slow retraction is sometimes desirable, of course, and some users find it difficult to adapt themselves to the necessity for rapid windup.

A primary object of the present invention is provision of locking and release mechanism for use in rotary cord reels or similar rotary devices adapted to either slow or rapid rotation in either direction.

Another object is elimination of a biasing spring for the pawl in a ratchet component of such mechanism.

A further object is accomplished of the foregoing objects by magnetic means.

Other objects of the present invention, together with means and methods for attaining the various objects, will be apparent from the following description and the accompanying diagrams, which are presented by way of example rather than limitation.

FIG. 1 is a side elevation of a cord reel in which the present invention is useful;

FIG. 2 is an edge elevation, partly in section, of the reel of the preceding view, taken at IIII thereon;

FIG. 3 is a side elevation of the same reel, taken at III-III thereon and partly cut away, showing the ratchet gear and pawl in engagement;

FIG. 4 is a fragmentary view similar to FIG. 3 but with the pawl occupying a neutral position relative to a desegmented portion of the gear;

FIG. 5 is a similar view differing only in having the supporting sheave displaced from the neutral position sufficiently for the pawl to encounter the segmented portion of the gear, as upon unwinding rotation of the reel;

FIG. 6 is a similar view but with the supporting sheave displaced oppositely so that the pawl encounters the segmented portion of the gear oppositely, as upon winding rotation of the reel;

FIG. 7 is a similar view but with the pawl shown in sliding disengagement with the gear, as upon continued winding rotation of the cord reel; and

FIG. 8 is a similarly fragmentary view of a modified embodiment of the invention.

In general, the objects of the present invention are accomplished, in locking and release means having ratchet mechanism useful in a cord reel or similar rotary device, by means of a gear having segmented and desegmented portions and a pawl engageable with the segmented portion of the gear and magnetically attracted theretoward. The pawl is adapted for engagement with the segmented portion when adjacent thereto and the pawl-supporting means is moving it in the unwinding direction (ratcheting) or has ceased doing so. The pawl also is adapted to occupy a position of minimum separation from such segmented portion when adjacent the latter and is further adapted to be deflected in the opposite direction into sliding nonratcheting contact upon rotation relative to the gear in the reverse or winding direction. The invention ensures further that the pawl always remains close enough to the gear, regardless of direction or speed of relative rotation, so that the magnetic field therebetween is sufficient to swing the pawl toward the gear.

FIG. 1 shows, from the side, cord reel 10 having support bracket 1 1 carrying sheave 12 for rotation relative thereto on an arbor (not visible) retained by screw 15. Visible flange 14 of the sheave carries retainer plate 16 affixed thereto by rivets 18. Cap 19 similarly secured to the retainer plate by double-ended rivets 17 has cutout portion 21, which exposes pivot pin 22 and head 23 of a rivet mounting pawl 24 (only the base thereof being visible). Electrical plug 8 on the end of cord 7 wound on the sheave of the reel appears at the top of the view.

FIG. 2 shows the cord reel of FIG. 1 edge-on and with part thereof sectioned to reveal the interior. Electrical cord 7 with plug 8 at the end thereof is cut away near the hub of sheave 12 for simplicity of the showing. It will be understood that the hub has two portions, one attached to flange l3 and the other attached to flange 14 of the sheave, and that the former contains electrical elements and the latter contains components of. a spring motor, as is conventional. Reference is made to my U.S. Pat. No. 2,948,913 for details of electrical and spring components, which are now conventional and, therefore, not illustrated or described further herein. An improved reel in which such components are disclosed is the subject of my copending application, Ser. No. 241,641 filed Apr. 6, 1972 now U.S. Pat. No. 3,813,501, for Electrical Cord-Reel Apparatus.

Those references are more concerned with such electrical and spring components, whereas the present disclosure is directed more toward mechanism for locking and releasing the reel and the cord carried thereon. However, in FIG. 2 the hub portion attached to flange 14 is cut away to reveal arbor 25 therein, especially an enlarged part thereof in which anchor slot 26 for the spring (omitted for clarity) is retained. Arbor end 29 is flattened on its opposite sides and thereby keyed to a complementary opening in the upstanding arm of the bracket. Intermediate portion 28 of the arbor is flattened similarly but at greater distance from the arbor axis and thereby keyed to ratchet gear 30, which has a complementary bore therethrough. Arbor portion 27 between the latter portion and the enlarged springreceiving portion is Cylindrical and constitutesa bearing surface about which flange 14 of the sheave and the elements carried thereby rotate. Located between gear 30 and retaining plate 16 is disclike magnetic element or washer 32, which is shown stippled to suggest its magnetic character.

FIG. 3 is a side view of the same cord reel sectioned just under cap 19 and showing the ratchet mechanism normally covered thereby. Gear 30 has segmented portion at its top and sides, as oriented in this view, and desegmented portion over approximately 120 of arc at the bottom. The dentate free end of pawl 24 as shown in solid lines is engaged between an adjacent pair of the dozen teeth (of about 20 extent each) shown on the segmented portion. Shown in broken lines is alternative disengaged position assumed by the pawl as the reel rotated clockwise about the gear, at the instant before the end of the pawl dropped into place. During such rotation, which corresponds to unwinding of the cord from the sheave, the pawl ratches relative to the gear, thereby preventing inadvertent releasing of the sheave for rotation in the windup direction. Provision for reversal of direction when desired is shown in the next view.

FIG. 4 shows neutral orientation of pawl 24 adjacent to the desegmented portion of gear 30, to which the pawl swings under the influence of the magnetic field provided by magnetized washer 32. It will be apparent that the sheave could continue to be rotated in the clockwise or unwinding direction as indicated by arrow CW, whereupon the pawl would be deflected from such neutral position into ratcheting position upon encountering the segmented portion of gear 30, with results just described and illustrated. FIG. shows the resulting orientation as the pawl encounters the first tooth of the segmented portion of the gear preliminary to ratcheting thereover. Alternatively, the sheave might be rotated in the opposite or counterclockwise (windup) direction as indicated by arrow CCW, whereupon the pawl would be oppositely deflected from its neutral po-,

sition (FIG. 4) by the segmented portion of the gear, as shown in FIG. 6, preliminary to sliding disengagement therewith.

FIG. 7 shows pawl 24 deflected into sliding disengagement with gear 30. The dentate end of the pawl is facing away from the gear teeth, and the rounded back of the pawl is contiguous with the outermost part of one or two of the gear teeth. In this position the sheave can be rotated indefinitely counterclockwise until the cord is fully wound thereonto, at the urging of the biasing spring (not shown), being so deflected each time the desegmented portion of gear 30 is encountered. When the pawl is so disengaged the direction of rotation of the sheave may be reversed and the sheave rotated clockwise, unwinding against the spring bias, until the pawl swings inward at the desegmented portion and is oppositely deflected by the segmented portion, whereupon the end of the pawl will engage the gear teeth in ratcheting contact therewith. Of course, when the sheave is being rotated in the unwinding direction, ratcheting of the pawl prevents the direction of rotation from being reversed until the pawl reaches the desegmented portion of the gear and swings into the neutral position permitted thereby.

It will be understood that the pawl should not be deflected so far as to escape the magnetic field set up by the magnetic washer. The invention provides precautionary means for ensuring against such escape. Thus, in FIG. 3 the edge of cap 19 restrains the pawl from disengaging from the gear much more than enough to clear the gear teeth. In FIG. 7 stop pin 36 on the opposite side of the pawl prevents excessive pivoting in the opposite direction when the pawl is slidingly disengaged.

FIG. 8 shows modified cap 19' sufficiently large in diameter to enclose entire pawl 24 as well as gear 30 and magnetic washer 32, as may be desirable to prevent foreign matter from entering and possibly interfering with the locking and release action. Except for the cap, all components remain as shown in precedingvicws. In addition, however, stop pin 38 located on the opposite side of pawl support 22 from stop pin 36 (visible in FIGS. 3 to 7) is added to prevent the pawl from being deflected away from gear 30, as by vigorous contact with the gear teeth upon unwinding (clockwise) rotation of the sheave upon which the pawl and its support and the covering cap are mounted.

Magnetized washer 32 preferably is composed of a resilient matrix made up of rubber or rubbery plastic material particles of permanently magnetizable material, such as ban'um ferrite. The particles preferably are dispersed throughout the matrix material while the latter is slowable. Then, after the matrix has hardened, the magnetizable particles are permanently crossmagnetized for polarization perpendicular to the direction along which the washer faces will be cut. Here the gear and retaining plate sandwich the washer, thereby concentrating and extending the magnetic field. The pawl on its pivot completes the magnetic circuit. All those elements preferably are composed of magnetically permeable material that is not permanently magnetizable, such as iron, soft or annealed steel, or cold-.

rolled steel.

Alternatively either the ratchet gear or the pawl (or both) may be made of permanently magnetized ferrous material. However, there is no necessity for doing so, and the foregoing magnetized washer is actually preferable for long life and dependability of magnetization at economical cost. The cap that covers the ratchet mechanism preferably is made of non-magnetizable material, such as aluminum, brass, or plastic.

The present invention provides a cord reel (of either electrical or non-electrical type) with a positive locking and releasing mechanism permitting continuous paying out of the cord against the retracting bias of the cordretracting spring, with a ratchet action to hold the cord at substantially any paid-out length. Alternatively, a slight tug on the cord will locate the ratchet pawl at a reversal point, corresponding to the desegmented portion of the ratchet gear, whereupon the cord may be released to wind continuously onto the sheave of the reel at the urging of the spring.

The magnetic design of this ratchet mechanism is free of the malfunctions that attend spring-biased ratchet pawls when the springs become weak, rusty, or broken. The positive action in both directions is free of stuttering or snagging, as often is encountered in the windup direction especially.

While a preferred embodiment and single modification of the invention have been described and illustrated, other modifications may be made therein, as by addition, combination, or subdivision of parts or steps, or by substitution of equivalents while retaining many of the advantages and benefits of the invention, which itself is defined in the following claims.

The invention claimed is:

1. ln locking and release means having ratchet mechanism useful in a cord reel or similar rotary device with an unwinding direction and a winding direction, the combination of a gear having segmented and desegmented portions and a pivotable pawl engageable with such segmented portion, one of these two mutually engageable members being magnetized and the other attracted theretoward by the resulting magnetic field for engagement therewith, the pawl being adapted to be in ratcheting engagement with the segmented portion when adjacent thereto during rotation in the unwinding direction and adapted to remain within the magnetic field and occupy a position of minimum separation from such desegmented portion when adjacent the latter and further adapted to be deflected in the opposite direction therefrom into sliding non-ratcheting contact with the segmented portion of the gear in the winding direction.

2. The ratchet mechanism of claim 1, wherein the gear is magnetized and the pawl is attracted theretoward.

3. The ratchet mechanism of claim 2, including permanent magnetic means closely adjacent the gear, both the gear and the pawl being magnetically permeable members with low magnetic retentivity.

4. The ratchet mechanism of claim 3, wherein the permanent magnetic means comprises a disc-like member contiguous with the gear and extending radially to the maximum radial extent of the gear teeth.

5. The ratchet mechanism of claim 4, wherein the pawl overlies part of the magnetic disc-like member when adjacent the desegmented portion of the gear.

6. In a rotary spring-biased cord reel having a ratchet gear and pawl locking and releasing mechanism, the improvement comprising a ratchet gear having a segmented portion engageable by the pawl to lock the reel from rotating in the biased direction to wind the cord thereonto and having a desegmented portion and past which the pawl can be deflected in either direction, means for establishing a magnetic field attracting the pawl toward the ratchet gear so as to engage with the segmented portion and to assume a neutral position within the magnetic field relative to the desegmented portion for deflection by the segmented portion upon rotation either to unwind or to wind up the cord, rotation in the unwinding direction being effective to deflect the pawl into ratcheting engagement with the segmented portion and rotation in the winding direction being effective to deflect the pawl into non-ratcheting engagement therewith.

7. Cord reel according to claim 6, including a pivot upon which the pawl swings and stop means located to preclude the pawl from swinging so far from the gear as to render the magnetic attraction therebetween ineffective.

8. Cord reel according to claim 7, wherein the stop means comprises a pin fixed laterally of the pivot location.

9. Cord reel according to claim 7, including a cover for the ratchet gear and pawl mechanism and wherein the stop means comprises an edge of the cover.

10. Cord reel spring-biased in windup direction comprising a frame supporting an arbor, a sheave supported for rotation in either direction about the arbor, a length of cord windable onto and unwindable from the arbor upon rotation of the sheave thereabout, magnetic ratchet gear-and-pawl locking and releasing mechanism wherein the gear has a segmented portion engageable by the pawl to lock the reel from rotating in the windup direction and has also a desegmented portion and past which the pawl can swing in either direction depending upon the direction of rotation of the sheave, rotation in the unwinding direction reengaging the pawl with the segmented portion but rotation of the sheave in the winding direction deflecting the pawl whereby the segmented portion will slide thereby without locking, the pawl being magnetically attracted toward the gear to engage with the segmented portion thereof when thereadjacent and to swing to a neutral position aligned between the pawl pivot and the axis of rotation of the sheave when adjacent the desegmented portion of the gear.

11. Cord reel according to claim 10, including a pair of stop pins, one on each side of the pawl pivot and adapted to prevent the pawl from swinging so far in either direction as to fail to be magnetically attracted to swing toward the gear.

12. In a spring-powered cord reel having a partially desegmented gear and having a rotational axis and a pawl movable relative thereto and engageable with a segmented portion of the gear, both the gear and the pawl being made of magnetically permeable material with low retentivity, the improvement comprising disclike permanent magnetic means adjacent one side of the gear and extending radially relative to the gear axis to the maximum extent of the segmented portion of the gear and circumferentially of the axis at such radial extent.

Claims

1. In locking and release means having ratchet mechanism useful in a cord reel or similar rotary device with an unwinding direction and a winding direction, the combination of a gear having segmented and desegmented portions and a pivotable pawl engageable with such segmented portion, one of these two mutually engageable members being magnetized and the other attracted theretoward by the resulting magnetic field for engagement therewith, the pawl being adapted to be in ratcheting engagement with the segmented portion when adjacent thereto during rotation in the unwinding direction and adapted to remain within the magnetic field and occupy a position of minimum separation from such desegmented portion when adjacent the latter and further adapted to be deflected in the opposite direction therefrom into sliding non-ratcheting contact with the segmented portion of the gear in the winding direction.

12. In a spring-powered cord reel having a partially desegmented gear and having a rotational axis and a pawl movable relative thereto and engageable with a segmented portion of the gear, both the gear and the pawl being made of magnetically permeable material with low retentivity, the improvement comprising disc-like permanent magnetic means adjacent one side of the gear and extending radially relative to the gear axis to the maximum extent of the segmented portion of the gear and circumferentially of the axis at such radial extent.