BACKGROUND OF THE INVENTION
This invention relates to coil spring winding devices for re-coiling spiral mainsprings and heavy spiral springs of the kind employed in large clocks, seat belt retractors, and recoil starters for internal combustion engines in chain saws, lawnmowers and the like. Spiral mainsprings of this type, fabricated of heavy spring steel band stock, require considerable energy for re-coiling, in order to supply great force during use. The task of securing the spiral spring during coiling and retaining the coiled spring ready for insertion in the spring housing of a clock, a motor or the like, is a time-consuming and burdensome one to mechanics and craftsmen. Even with the aid of needlenose pliers or clamping pliers of the "Vise Grip" type, manufactured by the Peterson Manufacturing Co. of Dewitt, Nebraska, such mainsprings often uncoil and escape during rewinding, frequently requiring a half hour or more of expensive labor time for re-coiling and reinstallation in their spring housings.
SUMMARY OF THE INVENTION
The rewinding devices or jigs of the present invention reduce spring re-coiling time to thirty seconds or less, by combining several mechanical actions to capture the powerful spiral mainsprings, to anchor each end securely, to retain the spring captive during the rewinding operation, to clamp the rewound spring in its re-coiled condition, securely latched against inadvertent uncoiling and escape, and also providing quick release of the re-coiled spring ready for insertion directly into its spring housing. The coil spring rewinding devices of this invention achieve these desirable objectives by providing a winding hub rotatably mounted on a sturdy base plate, and readily turned by a crank handle mounted on the opposite side of the base plate. Anchors securing the free end of the spiral spring are mounted on the base plate adjacent to the winding hub, and the hub is provided with an upstanding central post engaging a retainer bar, which is readily movable into engaged position to secure the spring captively on the winding hub and anchor without inhibiting its re-coiling movement. The crank is provided with an easily movable crankhandle, which may be extended for cranking rotation and retracted into latching interfering engagement with the base plate, securing the spring in its re-coiled condition.
Accordingly, a principal object of the present invention is to provide a coil spring rewinding device capable of securing powerful spiral springs captive during the rewinding operation, and holding them in rewound condition ready for insertion in their spring housings.
Another object of the invention is to provide coil spring rewinding devices achieving the foregoing objectives while providing ready access to the coil spring and its easy removability from the device.
A further object of the invention is to provide a coil spring rewinding device of the foregoing character incorporating a rewind crank having a handle movable from an extended winding position to a retracted latching position in which the re-coiled spring is clamped in its re-coiled condition.
Other and more specific objects will be apparent from the features, elements, combinations and operating procedures disclosed in the following detailed description and shown in the drawings.
FIG. 1 is a front elevation view of a coil spring winding device of the present invention showing the spring retainer bar disengaged and retracted for insertion of a spring over the crank hub.
FIG. 2 is a side elevation view of the device with its spring retainer bar engaged in spring-retaining position, and with the spring removed to show the construction of the device.
FIG. 3 is a rear elevation view of the same device showing a spring after re-coiling, with the crank handle in latched engagement with the base plate, securing the spring in its re-coiled condition.
FIG. 4 is an enlarged fragmentary side elevation view of the crank handle in latched engagement with the base plate.
FIG. 5 is an exploded cross-sectional side elevation view of the spring retainer bar-base plate mounting assembly and
FIG. 6 is a corresponding cross-sectional side elevation view of the same spring retainer bar-base plate mounting assembly in its assembled condition.
The preferred embodiment of the invention illustrated in the figures incorporates an elongated base plate 10 formed of sturdy steel bar stock, having a pair of protruding anchor studs 11, which may be roll pins or the like, projecting outwardly from the face of the base plate 10 near one corner thereof. Positioned near anchor studs 11 is a crank hub 12 provided with one or more angled peripheral notches for engagement with the inturned inner end of a spiral-wound clock-type mainspring 14, whose opposite outer free end is anchored engaging one of anchor studs 11, as shown in FIG. 1. Crank hub 12 is preferably formed as a cylindrical, drum-shaped hub keyed to a central mounting shaft 16 shown in FIG. 2. Shaft 16 extends through a hub aperture 17 formed in base plate 10 and through an external mounting sleeve 18 forming a rearward extension of base plate 10. Protruding from the rear end of sleeve 18, shaft 16 is keyed, welded or otherwise secured to a crank 19 provided with a movable handle 21. Rotation of handle 21 turns crank 19 about the axis of shaft 16 which revolves within sleeve 18 and aperture 17 in base plate 10, causing crank hub 12 to turn and apply winding torque to spring 14, and thus coiling it from the uncoiled condition shown in FIG. 1 to the coiled condition shown in FIG. 3. As indicated in FIGS. 2 and 4, crank handle 21 is easily movable axially through a handle aperture 22 formed in the free end of crank 19, being secured against removal from aperture 22 by terminal blind nuts 23 secured to each end of handle 21, preferably "acorn" nuts, as shown in the drawings.
When handle 21 is moved axially outward away from base plate 10, it protrudes in winding position (FIG. 1) ready for free cranking rotation about the axis of shaft 16, for rewinding coil spring 14 from its slack, relaxed condition shown in FIG. 1, to the coiled condition shown in FIG. 3. After rewinding is completed and coil spring 14 is tightly wound on a crank hub 12, handle 21 is moved axially through crank aperture 22 toward and past the plane of base plate 10 (FIG. 4), and the crank 19 is moved angularly in an unwinding direction, clockwise in FIG. 3, until the handle abuts the side edge of the base plate 10 in interfering engagement, as shown in FIGS. 3 and 4. In this position, handle 21 prevents further unwinding of spring 14, securing the wound spring in its tightly coiled condition as shown in FIG. 3, and is securely held in this interfering position by the uncoiling tendency of the re-coiled spring. In order to assure capture and retention of spring 14 during the coiling operation, a spring retainer bar 24 is pivotally secured to base plate 10 by a mounting assembly shown in FIG. 5 spaced a considerable distance away from crank hub 12. Spring retainer bar 24 is provided with a latching aperture 26 for engagement with the projecting free post end 16A of shaft 16, which protrudes beyond the face of crank hub 12, as shown in FIGS. 1 and 2.
The mounting assembly for spring retainer bar 24 illustrated in FIGS. 5 and 6 incorporates an arched "Belleville" spring washer 27 sandwiched between the front face of retainer bar 24 and the head of a shoulder mounting bolt 28. The enlarged shaft portion of bolt 28 extends through washer 27, through a mounting aperture formed in the end of retainer bar 24 and through a spacer block 29 which may take the form of a disk or a washer. The threaded end of mounting bolt 28 is anchored in threaded engagement within the threaded aperture 31 formed in base plate 10, with the shoulder bolt 28 being torqued into tight engagement with base plate 10. In this position, spring washer 27 urges retainer bar 24 resiliently into parallel alignment with base plate 10, with the latching aperture 26 of retainer bar 24 positioned in engagement with the protruding post end 16A of shaft 16, as shown in FIG. 2. Bar 24 may be angularly moved away from base plate 10, from the dash line position shown in FIG. 6 to the solid line position, lifting aperture 26 out of engagement with the protruding post end 16A of shaft 16, by resiliently deforming spring washer 27, and thus freeing bar 24 for angular pivoting disengagement movement about bolt 28 into the disengaged position shown in FIG. 1. This affords ready space for free removal of the coiled spring 14 shown in FIG. 3 and its replacement with a new spring in the uncoiled condition shown in FIG. 1, ready for re-coiling.
The unique simplicity of this coil spring rewinding device thus provides easy access to the re-coiled spring for its removal from the jig and insertion in its spring housing whenever desired. Until the spring is to be inserted in its housing, however, it is securely clamped in its wound condition by the interfering engagement of handle 21 with base plate 10, as shown in FIG. 4, and the rewound spring is held captive on crank hub 12 by the retainer bar engaged with shaft 16, as shown in FIG. 2.
The basic principle of the present invention may readily be employed with the rewind springs of recoil starters in internal combustion engines. To install a replacement pull cord, the spring must be re-coiled without being removed from the starter casing. This can be accomplished if the starter is removed and a crank is inserted in removable engagement with the toothed socket under the starter crank hub, provided the crank incorporates a movable crank handle similar to handle 19, retractable into latching interfering engagement with the starter casing as shown in FIG. 4, and thus holding the spring in re-coiled condition while a new starter cord is inserted and secured in place.
Since the foregoing description and drawings are merely illustrative, the scope of the invention has been broadly stated herein and it should be liberally interpreted to secure the benefit of all equivalents to which the invention is fairly entitled.