Abstract:
A starting device has a strip connected to a pulley for a pull start mechanism. The strip is composed of a high performance plastic and is provided with an integral handle. A connection means connects the strip to the pulley on its distal end. The strip fits neatly in a coil around a pulley hub. It lays flat during storage and exerts substantially no lateral pressure against the walls of the pulley. With this construction, the strip does not fray and affords a storing mechanism that is cleaner than a conventional rope system. The starting device has few parts and is easy to assemble. It is lightweight, inexpensive to construct and facilitates starting in an efficient, reliable manner.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. provisional patent application Ser. No. 60/138,204, filed Jun. 9, 1999. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a starting device for internal combustion engines; and more particularly to a starter strip operable to initiate movement of the drive shaft of a small engine during starting. 
     2. Description of the Prior Art 
     Starting mechanisms for internal combustion engines, for example small engines used in lawn and power applications, and even smaller engines designed for model planes and the like, need improvement. These mechanisms are typically of the rope and pulley type, and when used present the manufacturer and user numerous problems. 
     Some of the problems presented by conventional starting mechanisms include broken rope, tangled rope, spreading of the pulley sides, inconsistent pulls, jamming of the rope, wear on the rope, the expense of attaching handles, the attachment to the pulley, and the like. 
     A major complaint with conventional starting systems is that they are prone to failure and expensive to repair. Servicing these systems oftentimes entails labor intensive operations and testing, as well as added expense in materials for parts of the mechanisms involved: rope, knotting, handles and pulley design. Design requirements specified for rope systems make them difficult to construct and do not allow for starting mechanism that afford a consistent, non-obstructive wind up or pull. 
     It would be desirable to provide an improvement to the conventional rope and pulley mechanisms, which would alleviate these problems. 
     SUMMARY OF THE INVENTION 
     The present invention provides a starting device having a strip, which is connected to the pulley of a pull start mechanism. In one embodiment, the strip is composed of a high performance polymer, such as nylon, preferably Capron® nylon 6 from Honeywell International Inc. and can be provided with an integral handle, such as by molding. Preferably, the strip is made by injection molding, extrusion or other methods from a high strength material. The strip is connected to the pulley by a connection means on its distal end. The strip is designed to fit neatly in a coil around a pulley hub. 
     More specifically, the invention provides a starting apparatus for internal combustion engines, comprising an elongated flexible starter strip provided with a handle on a first end and a connection means on a second end. A housing partially encloses the apparatus and is provided with an opening for receiving the starter strip. A receptacle, provided with a central hub and a post, is fixed within the housing. Rotatably positioned on the hub is a starter pulley provided with a channel for storing the starter strip. The pulley has one or more slots for securely receiving the connection means. When thus received, the first end of the starter strip is secured to the starter pulley and the elongated starter strip is wound around the starter pulley within the channel. A spirally wound spring having inner and outer ends are provided for rewinding the starter pulley. The spring is positioned within the receptacle with its inner end fixed to the pulley and its outer end fixed to the post. A ratcheting means is provided for connecting the pulley to the drive shaft of the internal combustion engine. The ratcheting means provides for uncoupled rotation between the pulley and the drive shaft when the pulley rotates in the opposite direction of normal drive shaft rotation. Coupled rotation between the pulley and the drive shaft is also provided by the ratcheting means when the pulley rotates in the direction of normal drive shaft rotation. With this arrangement, the handle is pulled causing the strip to unwind. The spring becomes wound and the pulley rotates, causing the ratchet means to engage the drive shaft and start the engine. Upon release of the strip, the spring unwinds, causing the strip to be rewound on the pulley. 
     The starting device of this invention provides an efficient pulley design since the starting strip lays flat and exerts substantially no lateral pressure against the walls of the pulley. When constructed from a high strength plastic material such Capron® nylon 6 resin from Honeywell International Inc., the strip lasts longer than a conventional starter rope. In addition, with such construction, the starter strip does not fray and affords a storing mechanism that is much cleaner than a conventional rope system. 
     Advantageously, the present starting device can have an integral pulley handle. With this feature, the device has fewer parts. It is easier to assemble, owing to the absence of attachment points typically required for actuation with rope or cords (which are usually knotted). Lateral pressure on the pulley is virtually eliminated. Conventional rope/pulley constructions can be replaced by lightweight, inexpensive rewinding devices that facilitate starting in an efficient, reliable manner. The propensity for snagging, wedging or knotting of the starter cord is replaced by a consistent, non-obstructive wind up or pull. 
     Rope breakage is eliminated. A constant grab and pull accompanies each starting attempt. Engine powered units can be redesigned into units that are smaller, lighter, less expensive, more efficient and much more reliable in operation. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be more fully understood and further advantages will become apparent when reference is had to the following detailed description and the accompanying drawing in which: 
     FIG. 1 is an exploded view of the starter mechanism of this invention; 
     FIG. 2 a  is a perspective view of a first alternative connection means of the invention comprising a “T” shaped portion at the distal end of the starting strip for connection thereof to the starter mechanism; 
     FIG. 2 b  is a perspective view of a second alternative connection means of the invention comprising a jogged tab portion at the distal end of the starting strip for connection thereof to the starter mechanism; 
     FIG. 2 c  is a perspective view of a third alternative connection means of the invention comprising a mold snap portion at the distal end of the starting strip and an extension of the hub of the pulley having a window appointed for receiving the mold snap portion; 
     FIG. 2 d  is perspective view of a fourth alternative connection means of the invention comprising a forked shaped distal end of the starting strip formed of spaced tines for connection of the starting strip to the starter mechanism; and 
     FIG. 3 is a view of the starter mechanism in a power chain saw. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The starting strip of this invention is formed from a material, which is somewhat flexible. Such material is typically formed by molding or extruding the strip from a thermoplastic material. A preferred material is composed of a high performance polymer, such as a nylon, preferably Capron® nylon 6 from Honeywell International Inc. The strip is provided with a distal end for connection to the starter pulley of a conventional small gasoline engine, and an opposite end, which is adapted to be grasped by the user when the engine is to be started. The opposite end is preferably provided with an integral handle that can be readily grasped by the user, and may be of any suitable shape. For example, the strip may have the form of a plastic wire or the like. Those having skill in the art will appreciate that instead of being integral with the strip, the handle can be comprised of a separate part. 
     Referring to FIG. 1, the invention provides a starting apparatus for internal combustion engines comprising a starter strip  30  having an elongated flexible member  32  provided with a handle  34  on a first end and a connection means  38  on a second end. A housing  12  partially encloses the apparatus. Housing  12  is provided with an opening  17  for receiving the starter strip  30 . A receptacle  14  is provided with a central hub  18  and a post  15 . The receptacle  14  is fixed within the housing  12 . A starter pulley  22  is rotatably positioned on the hub  18  and provided with a channel  22   a  for storing the starter strip  30 . Pulley  22  has one or more slots  28  for securely receiving the connection means  38 . The first end of the starter strip  30  is secured to the starter pulley  22  and the elongated starter strip  30  is wound around the starter pulley  22  within the channel  22   a.  In the aspect of the invention depicted in FIG. 1, a means for connecting strip  30  to pulley  22  is provided by engagement of tab  36  in slot  26  located in flange  23   a.  Spirally wound spring  16  has inner end  15   b  and outer end  15   a.  The spring  16  is positioned within the receptacle  14  for rewinding the starter pulley  22 . Spring  16  has its inner end  15   b  fixed to the pulley  22  and its outer end  15   a  fixed to the post  15 . A ratcheting means  27  connects the pulley  22  to the drive shaft of the internal combustion engine. The ratcheting  27  means provides for uncoupled rotation between the pulley  22  and the drive shaft when the pulley  22  rotates in the opposite direction  29   b  of normal drive shaft rotation. In addition, ratcheting means  27  provides for coupled rotation between the pulley  22  and the drive shaft when the pulley  22  rotates in the direction  29   a  of normal drive shaft rotation. 
     In operation, handle  34  is pulled causing strip  30  to unwind and rotate pulley  22 . Ratchet means  27  is thereby caused to engage and rotate the drive shaft, starting the engine. Upon release of strip  30 , spring  16  unwinds. Strip  30  is thereby rewound on pulley  22 . 
     The starter strip  30  could be adapted for fast loading using a pre-designed bend as connection means  38 . In this embodiment, tab  36  provides means for connecting strip  30  to pulley  22 , as shown by FIG.  1 . This embodiment of starter strip  30  eliminates the crimping, sticking and other failures of wind up cord units. Also eliminated is the effect of dirt settling into the pulley mechanism and failures due to abrasion caused thereby. Alternate means for connecting strip  30  to pulley  22  are shown in FIGS. 2 a - 2   d  and described in detail hereinafter. 
     This invention delivers a more consistent pull because strip  30  comes straight off of the pulley  22 , rather than having to untangle itself from a developed nesting arrangement produced during winding of rope-type starting devices. The strip  30  has substantially uniform dimensions. It can be standardized and incorporated into a wide variety of engine units and products, all of which can be started thereby in an efficient, reliable manner. 
     Receptacle  14  has a central hub  18 , which is provided with an opening  19  for receiving screw  24 . Starter pulley  22  is disk shaped, comprising flanges  23   a  and  23   b  separated by hub  23 . This arrangement forms channel  22   a  adapted for winding and storing strip  30 . Hub  23  has opening  20  for receiving hub  18  of receptacle  14 . In this manner, pulley  22  is free to rotate about hub  18 . Pulley  22  is retained on hub  18  by means of a screw  24  and washer  26 . The screw  24  is secured in opening  19  of hub  18  to thereby retain both the starter pulley  22  and spring  16  within housing  12 . View A of FIG. 1 is a side view of pulley  22 . View B is a cross-section side view of pulley  22  and a partially wound starter strip  30 . 
     The starting mechanism described above with reference to FIG. 1 is a conventional spring-loaded mechanism. In accordance with another embodiment of the starting mechanism, one flange  23   a  or  23   b  of pulley  22  is provided with an attachment slot  28 . Starter strip  30  has an elongated central portion  32 , a handle  34  and a connection means  38 . Each of handle  34  and connection means  38  can be integral with the central portion  32 . Connection means  38  is provided with a generally L-shaped tab  36 , which is adapted to be received in slot  28 . 
     Starter pull strip  30  is formed of a flexible plastic material, such as nylon or other high strength material, by injection molding or other technique and shaped so as to fit neatly in a coil around hub  23  of pulley  22 . In the embodiment shown, starter strip  30  is composed of a high performance polymer, such as a nylon, preferably Capron® nylon 6 from Honeywell International Inc. Starter strip  30  is appointed to be wound between flanges  23   a  and  23   b  of starter pulley  22 , with tab  36  fitting into slot  28 , as shown by phantom lines in FIG.  1 . Strip  30  enters housing  12  through opening  17 . To actuate the starting mechanism, starter strip  30  is placed in the position depicted by FIG.  1 . Handle  34  is pulled to the right, as shown in the drawing. Such action causes rotation of starter pulley  22 , which is attached to the engine drive shaft in a conventional way (not shown). Such rotary motion of pulley  22  is imparted to the drive shaft, starting the engine. 
     Handle  34  and tab  36  are shown herein to be integral components of starter pull strip  30 . Such integral construction of the starter pull strip  30  is readily achieved by conventional forming operations, such as injection molding and the like. It will be appreciated by those skilled in the art that either or both of the handle  34  and tab  36  could comprise separate components that are attached by suitable fastening means to central portion  32  of pull strip  30 . 
     Referring to FIGS. 2 a - 2   d  of the drawings, there are shown several alternatives for attaching central flexible member  32  of pull strip  30  to pulley  22 . In a first of these alternatives depicted in FIG. 2 a,  connection means  38  is provided with a “T” shaped portion  40 . In this aspect of the invention each of starter pulley flanges  23   a  and  23   b  have slotted openings (not shown). The “T” shaped portion  40  is adapted to fit into slotted openings of pulley flanges  23   a  and  23   b,  shown in FIG.  1 . 
     In a second alternative for attaching the member  32  to pulley  22  shown in FIG. 2 b,  jogged tab  48  of connection means  38  is adapted to be inserted into slot  28 , shown in FIG.  1 . It will be understood by the skilled worker that other attachment alternatives may be provided to connect strip  30  to pulley  22 . 
     In a third attachment alternative shown in FIG. 2 c,  slot  28  takes the form of window  44  into which mold snap portion  41  of connection means  38  is adapted to be received. Hub  23  of pulley  22  has an extension  46  in which window  44  is provided. As illustrated in FIG. 2 d,  connection means  38  may alternatively be provided with a forked shaped end  42  formed of spaced tines adapted to be engaged in window  44 . 
     As a fifth attachment alternative pull strip  30  is integrated with hub  23  of pulley  22  during molding to provide a single integrally molded part. 
     Referring to FIG. 3 there is shown a portable chain saw  60 . Chain saw  60  includes a housing  62  which encloses the engine, and a housing  12  which encloses the starter assembly. Starter strip  30  is pulled by handle  34  and unwinds the starter strip wound within housing  12 . 
     The starting mechanism of the present invention can be used with a myriad of small engines. In addition to the power chain saw illustrated in FIG. 3, it may be utilized in a leaf blower, weed trimmer, and the like. The present invention is especially suited to be incorporated on most small engines in the same way that pulley and rope mechanisms are now provided. The entire system disclosed herein can be designed and adapted for use as part of a small engine unit. 
     Having thus described the invention in rather full detail, it will be understood that such detail need not be strictly adhered to but that further changes and modifications may suggest themselves to one skilled in the art, all falling within the scope of the invention as defined by the subjoined claims.