Abstract:
In an electronic component feeding device which comprises a component carrier tape wound around a reel, on which electronic components are accommodated in cavities formed on a support tape whose surface is covered by a removable top tape, a reel guide is pivotally mounted, which has a U-shaped cross section that resembles a hook, an open end of the hooked part being formed at a fixed angle θ, and which holds the reel when engaged with an outer peripheral edge of the reel.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to an electronic component feeding device that uses a component carrier tape in which chip-type electronic components are accommodated, and more particularly to an electronic component feeding device that feeds electronic components held in place on a carrier tape, while a top tape that covers the carrier tape is peeled away. 
     A conventional tape-type electronic component feeding device is described with reference to FIGS. 7 through 9. FIG. 7 shows a component carrier tape  100  which comprises a support tape  1  provided with cavities  2  for accommodating electronic components  3  therein. The support tape  1  is covered by a removable top tape  4  for preventing the electronic components  3  from jumping out of the cavities  2 . 
     As shown in FIGS. 7 and 8, the component carrier tape  100  is wound around a reel  7  that is fitted to a reel holder  6  provided at a proximal end of the electronic component feeding device  5 . A reel support pin  8 , provided in the reel holder  6 , is passed through a hole in the center of the reel  7 , and a reel guide  9 , that is pivotally mounted at one end  9   a , is engaged with an outer peripheral edge of the reel  7 , whereby the reel  7  is held in position. As is shown in FIG. 9B, the reel guide  9  has a U-shaped cross section and is mounted across the width direction of the outer edges of the reel  7  such that both side pieces  9   b  are engaged with the outer surfaces of the outer peripheral of the reel  7 . 
     The component carrier tape  100  is drawn out from the reel  7  and fed out by a tape feed wheel  11 , that is rotatably operated via upward and downward motion of a feed lever  10  on the electronic component feeding device  5 . The component carrier tape  100  is advanced at a distal end of the electronic component feeding device  5  such that it is pressed against a tape conveying surface  13  by a tape holder  12 . As the component carrier tape is fed at a specified pitch by the tape feed wheel  11 , the top tape  4  is peeled off via a slit  14  provided in the tape holder  12 , and the electronic components  3  are removed by a suction nozzle  15  at a predetermined location. 
     The top tape  4  thus removed is wound onto a take-up cap  17  that is disposed downstream of the tape holder  12  in the advancing direction of the component carrier tape  100 . The take-up cap  17  is mounted on a ratchet mechanism  16  that turns only in one direction through a reciprocating action of the feed lever  10 . 
     In the above described conventional configuration, the reel guide  9  has a U-shaped cross-section of a fixed width and holds the reel  7  by being mounted across the width direction; it therefore cannot accommodate variations in the width of the reel  7 . For example, if the width of the reel  7  is large, then the reel guide  9  will apply a large resistance to the rotation of the reel  7 , which could result in an unstable delivery of the component carrier tape  100  from the reel  7 . Further, as shown by the arrows in FIG. 9B, the difference in the width direction of the force working on the reel guide  9  creates a torsional moment, which makes it difficult to maintain reel guide  9  rigidity. Moreover, since the reel guide  9  cannot be used for various components of different dimensions respectively accommodated in tapes of different widths, a special reel guide  9  must be provided for each type of electronic component feeding device  5 . 
     SUMMARY OF THE INVENTION 
     In view of the foregoing, it is an object of the present invention to provide an electronic component feeding device that can effect a stable feed of component carrier tapes of various sizes from reels of different dimensions. 
     An electronic component feeding device of the present invention comprises a reel guide which is pivotally mounted on a reel holder and which has a U-shaped, hook-like cross section. The reel guide is engaged with an outer peripheral edge of a reel thereby holding the reel. A distal end of the hooked part of the reel guide is formed such as to open outwardly at a fixed angle in relation to a wall of the reel. With the distal end of the hooked part of the reel guide formed such as to open outwardly at a fixed angle, reels of differing dimensions in the width direction can be stably held. 
     The reel guide can be made thin if it is constructed such as to engage with only one side wall of the reel. Moreover, a torsional force does not act on the reel guide as it does when the reel guide is engaged across the entire width of the reel, and therefore the rigidity can be increased. A common reel guide can thus be used for various reels of different dimensions. 
     The reel guide may be biased against the reel by means of a spring thereby holding the reel with a certain force. The reel guide with its hooked part formed at a fixed angle can thus stably hold reels of differing dimensions, as it engages closely with the outer edges of the reel without any gaps there between. 
     If a plurality of reel support points are provided to the reel holder so as to be selectively used in accordance with the reel size, the reel holding force of the reel guide can be kept constant, and reels of various dimensions can be accommodated in a common reel holder. 
     The reel holder may be made removable from the main body of the electronic component feeding device, whereby a common reel holder can be used in various electronic component feeding devices respectively accommodating different types of components of various different sizes and shapes. 
    
    
     While novel features of the invention are set forth in the preceding, the invention, both as to organization and content, can be further understood and appreciated, along with other objects and features thereof, from the following detailed description and examples when taken in conjunction with the attached drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front view of an overall configuration of a first embodiment of an electronic component feeding device of the present invention; 
     FIG. 2 is an enlarged front view of a reel holder of the above embodiment; 
     FIG. 3A is a plan view and FIG.  3 B and FIG. 3C are cross-sectional views, showing a reel and a reel guide of the above embodiment; 
     FIG. 4 shows an enlarged front view of a reel holder of a second embodiment of the present invention; 
     FIG. 5 shows an enlarged front view of a reel holder of a third embodiment of the present invention; 
     FIG. 6 shows an exploded front view of an overall configuration of a fourth embodiment of an electronic component feeding device of the present invention; 
     FIG. 7 shows a perspective view of a general configuration of a pertinent portion of a conventional electronic component feeding device; 
     FIG. 8 shows a front view of an overall configuration of the conventional electronic component feeding device; and 
     FIG. 9A is a plan view and FIG. 9B is a cross-sectional view showing a reel and a reel guide of the above conventional electronic component feeding device. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Preferred embodiments of the electronic component feeding device of the present invention will be hereinafter described with reference to the accompanying drawings. 
     A first embodiment of the present invention is described with reference to FIGS. 1 to  3 . An overall configuration of the electronic component feeding device  5  is the same as that described with reference to FIGS. 7 and 8, and same or similar elements are given the same reference numerals and the description omitted so that only particular elements of the present embodiment are described. 
     The overall configuration of the electronic component feeding device  5  is shown in FIG. 1. A reel holder  6  holds a reel  7  on which a component carrier tape is wound. A reel support pin  8  is provided to support the reel holder  6 . As shown in FIG. 2, the reel  7  is provided with a hole in the center through which the reel support pin  8  is passed. A reel guide  21  is engaged with an outer peripheral edge of the reel  7  and thereby holds the reel  7 . 
     As shown in FIGS. 2,  3 A, and  3 B, the reel guide  21  is lever-shaped and one end  21   a  thereof is pivotally mounted on the reel holder  6  such that it can move upwards and downwards over a predetermined range. Its main portion has a U-shaped cross section that resembles a hook, an open end of the hooked part being set at a fixed angle θ; the open end of the hooked part  22  of the reel guide  21  holds the reel  7  when engaged with an outer peripheral edge of one of side plates  7   a  of the reel  7 . The function of the hooked part  22  is evident if the open angle θ is greater than 0° and less than 90°, but it is preferable for the angle to be in the range of 10° to 45°. 
     According to this embodiment of the present invention, the reel guide  21  is shaped so as to have a cross-sectional shape that is set at a fixed angle θ on its open side; therefore any variation in the width dimension of the side plates  7   a , as shown in FIGS. 3B and 3C, is compensated for by the depth of contact with the hooked part  22  without applying large resistance. As a result, the reel  7  is stably held. In particular, the reel guide  21  of this embodiment is engaged with an outer peripheral edge of one side plate  7   a  of the reel  7 , and therefore the reel guide  21  can be made thin enough so that the only force which acts on the support point of the reel guide  21  is the force around the support point within a plane including the support point. That is, no torsional force acts on the reel guide  21  in a direction orthogonal to the plane including the support point of the reel guide  21 , wherefore the rigidity of the reel guide  21  can be increased. Thus a common reel guide can be used for reels  7  with various dimensions in the width direction. 
     In the above embodiment the reel guide  21  is configured so as to be engaged with the outer edge of one side plate  7   a  of the reel  7 , but the width dimension of the reel guide  21  can be configured to match the width dimension of the reel  7  to enable contact with the outside of the outer edges of both side plates  7   a ,  7   a  of the reel  7 . 
     FIG. 7 shows a second embodiment of the present invention. Descriptions of the same elements as those used in the first embodiment are omitted, with only the differences being described. 
     In this embodiment the reel guide  21  is configured so as to be pressed against a side of the reel  7  by a spring  23  with a force of 100 g to 200 g. A coil spring is preferred for use as the spring  23 , but any spring besides a coil spring or any non-spring elastic body may also be used for the spring  23 . 
     According to the present embodiment, the reel guide  21  is pressed against the reel  7  by the spring  23 , enabling the reel guide to hold reels of differing dimensions stably by maintaining continuous contact with an outer edge of same without any gaps occurring there between. 
     FIG. 5 shows a third embodiment of the present invention. Descriptions of the same elements as those used in the first and second embodiments are omitted, with only the differences being described. 
     In this embodiment the reel guide  21  is pressed against the reel  7  by the spring  23  and the reel holder  6  is provided with a plurality of holes  24  in which a reel support pin  8  is fitted, so that the reel support pin  8  can be held in place in the desired hole  24  by a screw (not shown) in accordance with the diameter of the reel  7 . 
     According to the present embodiment, the holes  24  for holding the reel support pin  8  can be selected according to the reel diameter and thereby allow the reel guide  21  to press against the reel  7  with a fixed force. In other words, the force of pressure applied to the reel  7  by the reel guide  21  via the spring  23  changes depending on the angle attitude of the reel guide  21  and its point of contact with the reel  7 . When the size of the reel  7  changes, therefore, the contact point between the reel guide  21  and the reel  7  changes over the range b 1  to b 2  and the angle at which the reel guide  21  is brought into contact with the reel  7  (the angle from position B on the reel guide  21  when a reel  7  is not installed) accordingly changes over the range c 1  to c 2 , thereby keeping the pressure force constant. 
     The above function will be evident at a force of pressure in the range of 50 g to 500 g, but a range of 100 g to 200 g is preferable. 
     FIG. 6 shows a fourth embodiment of the present invention. Descriptions of the same elements as those used in the first through third embodiments are omitted, with only the differences being described. 
     In this embodiment the reel holder  6  is configured as an independent component that can be attached to and detached from the electronic component feeding device  5  and can be held in place by screws. 
     According to the present embodiment the reel holder  6  can even be attached to electronic component feeding devices  5  that use component carrier tapes of different shapes. 
     Although the present invention has been fully described in connection with the preferred embodiment thereof, it is to be noted that various changes and modifications apparent to those skilled in the art are to be understood as included within the scope of the present invention as defined by the appended claims unless they depart therefrom.