Abstract:
A rivet carrier for use in association with a driver for driving rivets into a work piece. The rivet carrier includes mounting structure for mounting the rivet carrier on the driver. A body portion of the rivet carrier is in communication with the mounting structure for receiving and retaining the rivet for engagement by the driver. Angled rollers are disposed in the body, and there are pivotable arms in the body. A resilient member retainably engages the pivotable arms. The rollers are retained in recesses in the body, and at least a portion of the pivotable arms defines at least a portion of the recesses. Preferably, a pair of outlet vents are provided in the body of the rivet carrier for venting air which is used to drive the rivet. One outlet vent may be proximate the other outlet vent to create laminar air flow.

Description:
RELATED APPLICATION 
     This application claims the benefit of U.S. provisional application Serial. No. 60/212,306, filed Jun. 17, 2000. 
    
    
     BACKGROUND 
     This invention generally relates to rivet carriers, and more specifically relates to a rivet carrier which is configured to prevent jamming and reduce turbulence and movement during use. 
     Rivets are used in a variety of applications in order to attach a component to a workpiece or two workpieces together. In machines which automatically deliver rivets to a driving head, the driving head includes a carrier head in which the rivet is properly positioned and aligned prior to driving. One of the problems with the driving heads is that the rivets tend to get caught in the carrier head, making installation of the rivet into the workpieces difficult. Additionally, if the rivet is not properly positioned and served relative to the workpiece, it can jam the carrier. Since such machines are intended to be generally automated in terms of delivery of the rivet to the carrier head and installation of the rivet into the workpieces, jamming of such an automated machine dramatically reduces the operating efficiencies of such a system. 
     Many prior art devices tend to deliver rivets to a carrier head in an inconsistent manner. Such inconsistency in delivery of the rivets to the carrier head may produce jamming causing damage to machine components possibly resulting in production downtime. Additionally, many prior art devices provide much turbulence or movement during use, and this is undesirable. 
     The present invention is an improvement to the carrier head in order to control the position and orientation of rivets received therein, and to reduce turbulence and movement during use. 
     OBJECTS AND SUMMARY 
     A general object of an embodiment of the present invention is to provide a rivet carrier which is configured to prevent the jamming of rivets. 
     Another object of an embodiment of the present invention is to provide a rivet carrier which is configured such that turbulence and movement during use is reduced compared to some prior art devices. 
     Briefly, and in accordance with at least one of the foregoing objects, an embodiment of the present invention provides a rivet carrier for use in association with a driver for driving rivets into a work piece. The rivet carrier includes mounting structure for mounting the rivet carrier on the driver. A body portion of the rivet carrier is in communication with the mounting structure for receiving and retaining the rivet for engagement by the driver. Rollers are disposed in the body for retaining the rivet therein until the rivet is engaged by the driver and pushed past the rollers. The body has a longitudinal axis, and the rollers are angled relative to the longitudinal axis. There are pivotable arms in the body, and the pivotable arms are configured to engage the rivet therein. A resilient member retainably engages the pivotable arms. The rollers are retained in recesses in the body, and at least a portion of the pivotable arms defines the recesses. Preferably, a pair of outlet vents are provided in the body of the rivet carrier, and the outlet vents are configured to allow the venting of air which is used to drive the rivet. One outlet vent may be proximate the other outlet vent to create laminar air flow. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The organization and manner of the structure and operation of the invention, together with further objects and advantages thereof, may best be understood by reference to the following description, taken in connection with the accompanying drawings, wherein like reference numerals identify like elements in which: 
     FIG. 1 is a view showing a riveting machine which includes a rivet carrier that is in accordance with an embodiment of the present invention; 
     FIG. 2 is a top plan view of the rivet carrier shown in FIG. 1; 
     FIG. 3 is a front elevational view of the rivet carrier shown in FIG. 1; 
     FIG. 4 is a right side elevational view of the rivet carrier shown in FIG. 1; 
     FIG. 5 is a partial fragmentary cross-sectional view of the rivet carrier taken along line  5 — 5  of FIG. 4; and 
     FIG. 6 is a partial fragmentary cross-sectional top plan view of the rivet carrier taken along line  6 — 6  of FIG.  4 . 
    
    
     DESCRIPTION 
     While the present invention may be susceptible to embodiment in different forms, there is shown in the drawings, and herein will be described in detail, an embodiments thereof with the understanding that the present description is to be considered an exemplification of the principles of the invention and is not intended to limit the invention to that as illustrated and described herein. 
     With reference to FIGS. 1-6, a form of a riveting machine and carrier head are shown and described herein. With reference to FIG. 1, a riveting machine  20  is shown having a rivet carrier or carrier head  22  mounted thereon. The carrier head  22  receives rivets  24  which are delivered thereto along a path of travel  26 . The rivets  24  are carried along the path of travel  26  by positive air flow traveling towards the carrier head  22 . 
     The rivet  24  as shown and described herein is generally of a type having an enlarged head. A side elevational view of such a rivet defines a “T”-shaped configuration. 
     The machine  20  includes a driver  28  which drives the rivets  24  delivered to the carrier head into work pieces  32  along an axis  30 . During the driving operation, the rivet  24  is retained in the carrier head  22  until it is appropriately served and positioned relative to the work pieces  32 . Once the rivet is installed in the work pieces  32 , the carrier head  22  returns to receive another rivet. 
     The carrier head  22  of the present invention includes improvements which allow the carrier head to receive and retain the rivet. The improvements prevent the rivet from jamming the carrier head and reduce turbulence and movement of the rivet within the carrier head  22 . 
     With reference to FIGS. 2-6, various views of the carrier head are shown. The carrier head  22  includes a rivet receiving and head mounting plate  34 . This attaches to a portion of or proximate to the driver  28 . The carrier head  22  includes a positioning and retaining structure  36  approximate to the plate  34 . A rivet is shown in FIG. 5 positioned within the carrier head  22  for installation. 
     With reference to FIG. 2, the path of travel  26  indicates that the rivet is delivered generally axially relative to the plate  34 . Walls  38  defining a mouth  40  of the plate  34  are tapered from the open end of the mouth  40  inwardly towards a driving passage  42 . The tapered walls  38  facilitate proper transfer of the rivet to the carrier head  22  and alignment with the passage  42 . It should be noted that with reference to FIG. 3, the walls  38  are tapered to accommodate the enlarged head of the rivet. It should be noted that the lower portion of the rivet also is received in an area in which the walls  44  are tapered inwardly also promoting proper transfer and alignment of the rivet in the driving passage  42 . 
     The positioning and retaining portion or “body” includes a pair of pivotable arms  46  which are positioned generally opposite one another. The arms  46  are retained in corresponding channels  48  in the body  36 . An O-ring or resilient holder  50  retains the arms  46  in the channels  48 . Upper and lower extensions  52 ,  54  of the arms  46  abut corresponding structures to prevent inward movement of the arms  46 . As such, the arms  46  are pivotally retained on the body  36  as described in the foregoing and will be further described hereinbelow. 
     Towards the upper portion of the body  36 , a pair of generally oppositely positioned rollers  56  are retained in appropriately sized and dimensioned recesses  58 . A portion of the recess  58  intersects the driving passage  42  to allow a portion of the roller  56  to extend into the diving passage  42 . An inside edge of the recess relative to the driving passage  42  prevents inward movement of the roller  56  beyond a predetermined point. The upper portions  52  of the arms extend into the corresponding roller recesses  58  to prevent outward movement of the roller  56 . The resilient holder  50  allows a degree of movement of the roller  56  such that, as described hereinbelow, as force is applied to the rivet, the rivet can push the rollers  56  outwardly relative to the driving passage  42 . Once the rivet head has passed, the rollers are resiliently returned to the inward position as a result of the compressive force by the resilient holder  50 . 
     It should be noted that it is envisioned that various constructions of the rollers, arms and resilient holder may be used to achieve the objectives of the present invention. As such, the structure and function of these features should be broadly interpreted. 
     It should be noted that the rollers  56  as shown in FIG. 6 are angled relative to an axis  60 . Preferably, the taper or angle  67  is in the range of 3 to 9 degrees, and as shown in FIG. 6, is most preferably approximately 6°. It is envisioned that the taper or angle may be selected as appropriate based on various parameters associated with the particular type of rivet, material, installation procedure as well as other factors. The angle on the rollers helps to align and retain the rivet once it is delivered to the carrier and driving passage  42 . It should be noted that the driving passage generally has a diameter which is equal to or slightly larger than the diameter of the head of the rivet. This diameter can be achieved in the carrier head by movement of the rollers  56  and the arms  46 . Nevertheless, the functional diameter of the passage  42  is equal to or slightly greater than the diameter of the head of the rivet  24 . 
     The rivet head  24  is positioned above the rollers  56  (see FIG. 5) to retain the rivet in the desired position in the driving passage  42 . The spring biased configuration and orientation of the rollers  56  relative to the rivet  24  allow a degree of retaining force on the rivet. The retaining force allows some degree of clamping by the driver  28  (shown diagrammatically) in FIG. 5 to be applied to the rivet head to retain it in position while the carrier head  22  is positioned relative to the workpieces  32 . 
     Once the carrier head  22  is properly positioned relative to the workpieces, the driver  28  drives the rivet axially along the axis  62  to install the rivet into the workpieces. During the driving operation, the rivet is pushed past the rollers  56 . This occurs when the driving force is greater than the inward spring force on the rollers. When this occurs, the rollers are pushed outwardly against the spring force created by the holder, thereby pivoting the upper portion  52  of the arms  46  outwardly as the rivet passes the rollers. As the rivet travels downwardly through the driving passage  42 , it encounters inwardly sloped edges  64  of the arms  46 . As it passes the edges  64 , it pushes the rollers inwardly and pivots the lower portions  54  of the arms  46  outwardly. 
     With further reference to the FIGS. 2,  3 ,  4  and  6 , outlet vents  66  are provided in the carrier proximate to and communicating with the driving passage  42 . As described above, the rivet  24  is delivered to the carrier head  22  along a path of travel  26  by means of air flowing through a tube  68 . When the air flow terminates at the driving passage  42 , since the air cannot escape, it tends to create turbulence and move the rivet within the passage or cause the rivet to bounce back once it hits the carrier. 
     The carrier head  22  of the present invention includes the outlet vents  66  to exhaust the flow of air, as indicated by arrows  69  in FIGS. 2,  4  and  6 , from the tube  68 . By exhausting the air, the air generally does not circulate within the driving passage  42  and therefore generally does not have an effect on the rivet positioned therein. In fact, the exhausting of the air through the vents  66  tends to stabilize the position of the rivet relative to the driving passage  42 . As shown in FIGS. 3 and 4, two pairs of outlet vents  66  are provided at spaced apart locations relative to the driving passage  42 . These vents are located at an angle relative to the path of travel  26 . The vents are sized and dimensioned to accommodate the air flow to prevent back flow of air or pressure within the driving passage  42 . As shown in FIG. 4, the pair of vents on each side are generally spaced one above the other. This creates laminar air flow which helps retain the lower portion of the rivet generally axially aligned with the axis  62 . The positive air flow against the rivet also retains the rivet against the smaller portion of the angled rollers  56 . The angled rollers create a wedging effect against the lower portion of the rivet and retain the upper portion of the rivet thereagainst. The air flow helps maintain the wedging effect. 
     In use, a rivet  24  is carried through the tube  68  along the path of travel  26  by air flowing through the tube  68 . The rivet  24  is delivered to the carrier head  22 . As it approaches the carrier head, the rivet is guided in the transition from the tube to the carrier head by the angled walls  38  and  44 . The rivet stops traveling when it becomes positioned against the rollers  56  in the driving passage  42 . The rollers hold the rivet in position prior to insertion. The air flow flowing along the path of travel  26  is exhausted through the outlet vents  66  to help retain the orientation of the rivet within the driving passage against the rollers  56 . The driver  28  drives against the rivet  24  to impose forces on it to drive it past the rollers  56 . As forces increase, the rollers ultimately pivot outwardly to allow the rivet  24  to pass thereby against the inward forces of the resilient holder  50 . The arms  46  are pivotable inwardly and outwardly to allow passage of the rivet as described above. 
     While embodiments of the present invention are shown and described, it is envisioned that those skilled in the art may devise various modifications of the present invention without departing from the spirit and scope of the appended claims.