Abstract:
A conveyance system has movable guide rails that can be positioned close to one another when small packages or articles are carried by the system or further apart from one another if the conveyed packages or articles are large. The spacing between the guide rails is controlled by a linkage arrangement that includes a center link mounted for conjoint rotation on a longitudinally disposed drive shaft. Each opposite end of the center link is pivotally attached to an outer link and the outboard end of each outer link is pivotally mounted to a slideably mounted mounting block to which is secured a rail support for holding a guide rail. The drive shaft is rotated manually through a control knob or the rotation is performed by a reversible motor. Alternatively, a bell crank rotates the drive shaft in a first direction to cause convergence of the guide rails and in a second, opposite direction to cause divergence of the guide rails. In a second embodiment, the conveyor system has a curvature formed in it. Curved guide rails have guide rail extensions slideably mounted to them at their opposite ends to enable the guide rails to be effectively lengthened and shortened when the space between them is increased or decreased, respectively.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates, generally, to conveyance systems. More particularly, it relates to a versatile conveyance system that can accommodate packages of varying widths. 
     2. Description of the Prior Art 
     In conventional conveyor belt systems, a pair of fixed position guide rails flank the conveyor belt. These systems work well in those applications where the breadth of the packages, containers, or other objects being conveyed from one point to another are of a common breadth. However, they cannot be used in a conveyor system that handles objects of varying widths. 
     Where objects of varying widths are to be conveyed, the transverse or lateral spacing of the guide rails must be adjustable. Inventors have developed several conveyor systems having adjustable guide rails. For example, U.S. Pat. No. 5,211,280 to Houde discloses an assembly where the position of one of the guide rails may be adjusted by a rack and pinion assembly. The position of the other guide rail, however, cannot be changed by said rack and pinion assembly. An internal cam mechanism is employed to adjust the lateral spacing between guide rails in the structure disclosed in U.S. Pat. No. 5,291,988 to Leonard. A tapered clamp performs that function in the assembly disclosed in U.S. Pat. No. 5,626,221 to Ledingham. U.S. Pat. No. 5,692,596, also to Ledingham, discloses a split support rod held by a clamp. Another clamp assembly is disclosed in U.S. Pat. No. 5,701,991 to Helmetsie. U.S. Pat. 6,050,396 to Moore discloses a rack and pinion assembly that interconnects both guide rails to a single pinion. There are at least another half dozen patents disclosing other mechanisms for varying the transverse or lateral spacing between longitudinally extending guide rails. 
     All of the earlier assemblies perform their respective intended functions. However, they are mechanically complex and as a result they require frequent maintenance and adjustment. Such work sometimes requires that the conveyor line be shut down at great expense. What is needed, then, is a much simpler assembly that requires minimal maintenance and adjustment. 
     Some of the earlier assemblies also have width-adjustment means the operation of which is time-consuming. For example, one embodiment of the &#39;396 patent to Moore requires an operator to manually turn a knob to effect rotation of a drive shaft that carries a pinion gear that is meshingly engaged to rack gears upon which are mounted rail supports that carry the guide rails of the system. It is a time-consuming job to rotate the knob until the desired spacing between guide rails has been achieved. Moreover, rack and pinion gears are not easy to fabricate and they may disengage from one another. In another embodiment of the Moore assembly, a reversible motor performs the shaft rotation function. However, such motors are not inexpensive. In both the rack and pinion embodiment and the reversible motor embodiment, there is no easy way to lock the guide rails into position once the desired spacing has been achieved. 
     What is needed, then, is a better means for adjusting the spacing between conveyor system guide rails. The improved means should neither require nor exclude use of a motor. However, it should enable a machine operator to manually perform the width adjustment in a very precise, fast and easy way. Moreover, a self-locking means is needed as well. 
     However, in view of the prior art in at the time the present invention was made, it was not obvious to those of ordinary skill in the pertinent art how the identified needs could be fulfilled. 
     SUMMARY OF THE INVENTION 
     The longstanding but heretofore unfulfilled need for a conveyor apparatus of elegant yet effective design is now met by a new, useful, and nonobvious invention that has utility in conveyor and conveyance systems. 
     The novel apparatus for varying the lateral spacing between guide rails in a conveyor assembly or conveyance system includes a straight drive shaft of elongate construction that is mounted for rotation about a longitudinal axis of rotation. A rotation means is provided for selectively rotating the drive shaft in a first direction about its axis of rotation and in a second direction about said axis, the second direction being opposite to the first direction. The rotation means includes a linkage means formed by a rigid center link and two rigid outboard links. All of the links are of flat, straight configuration. The center link is centrally apertured to accommodate the drive shaft. Moreover, the center link is mounted for conjoint rotation with the drive shaft so that rotation of the drive shaft effects simultaneous and corresponding rotation of the center link. In a preferred embodiment, the drive shaft is noncircular in transverse section and the central aperture formed in the center link is complementally formed therewith. The center link is pivotally connected at its opposite, outboard ends to inboard ends of the respective outboard links. Each outboard link has an outermost free end and a slideably mounted mounting block is pivotally connected to the respective outermost free ends of the outboard links. An upstanding rail support member is mounted to each of the slideably mounted mounting blocks. A first guide rail is mounted to a first rail support member and a second guide rail mounted to a second rail support member. 
     Accordingly, rotation of the drive shaft in a first direction effects convergence of the first and second guide rails and rotation of the drive shaft in a second direction opposite to said first direction effects divergence of the first and second guide rails. 
     Several means are disclosed for enabling rotation of the drive shaft. In one embodiment, a control gear is mounted on the drive shaft for conjoint rotation therewith in longitudinally spaced apart relation to the center link so as not to interfere therewith and a pinion gear is disposed in meshing engagement with the control gear. The pinion gear is mounted for conjoint rotation at the distal end of an elongate control shaft having a control knob mounted on a proximal end thereof for conjoint rotation therewith. In this way, manual rotation of the control knob in a first direction effects rotation of the control gear and hence said drive shaft in said first direction. Manual rotation of the control knob in a second direction opposite to the first direction effects rotation of the control gear and hence the drive shaft in a second direction. 
     A second means for enabling rotation of the drive shaft includes a reversible motor means having an output shaft secured to the drive shaft for conjoint rotation therewith. 
     A third means for enabling rotation of the drive shaft includes a bell crank means having a first end mounted to the drive shaft for conjoint rotation therewith and a second end, disposed at a fixed angle to the first end, to which is pivotally secured an elongate control arm. 
     There are three illustrative means for effecting rotation of the bell crank, although equivalent means are within the scope of this invention. 
     A first means is manual, i.e., a second or free end of the elongate control arm is adapted for manual engagement so that manual displacement of the elongate control arm in a first direction effects rotation of the drive shaft in a first direction and manual displacement of the elongate control arm in a second direction effects rotation of the drive shaft in the second direction. 
     In a second means, an elongate screw actuator pivotally engages and displaces the free end of the control arm. 
     A third means includes a pneumatic cylinder that pivotally engages the second end of the control arm. Both the screw actuator and the pneumatic cylinder provide enhanced utility because such mechanisms enable locking of the guide rails into a preselected position when the desired spacing has been set. 
     Guide rail sections having a bend or curvature formed therein may also be employed to enable the conveyor or conveyance assembly to follow a curved path of travel. Extension guide rails of straight configuration are slideably mounted to the curved guide rail sections and are connected thereto by a stop block and rod assembly. The opposite ends of each curved guide rail section are axially bored to slideably receive an associated rod and the free end of each rod is secured to a stop block that surmounts the extension guide rails. 
     Thus it is understood that the primary object of the invention is to provide a novel conveyance apparatus that provides adjustable width guide rails but which has a small number of moving parts and which is free of gear arrangements. 
     A closely related object is to provide such a reliable and durable apparatus that minimizes maintenance problems and thus conveyor belt downtime. 
     Still another important object is to provide a control means that enables a machine operator to vary the lateral spacing between guide rails in a fast, precise, and easy way, free of control knobs and motors. 
     Yet another important object is to provide a mechanism that is self-locking so that the spacing between guard rails remains the same during operation of the apparatus. 
     These and other important objects, advantages, and features of the invention will become clear as this description proceeds. 
     The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts that will be exemplified in the description set forth hereinafter and the scope of the invention will be indicated in the claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a fuller understanding of the nature and objects of the invention, reference should be made to the following detailed description, taken in connection with the accompanying drawings, in which: 
     FIG. 1 is an exploded perspective view of a prior art assembly; 
     FIG. 2 is an assembled, front elevational view thereof; 
     FIG. 3 is an exploded perspective view of a second embodiment of the prior art assembly; 
     FIG. 4 is a perspective view of a prior art embodiment having a curvature formed therein; 
     FIG. 5A is a front elevational view and the first figure of an animation depicting the sequential positions of a linkage that are displaced in diverging relation to one another to increase the lateral spacing between them; 
     FIG. 5B is the second figure of said animation; 
     FIG. 5C is the third and last figure of said animation; 
     FIG. 5D is a top plan view of the novel structure; 
     FIG. 5E is a front elevational view thereof; 
     FIG. 5F is an end elevational view thereof; 
     FIG. 6A is a front elevational view and the first figure of an animation depicting a novel control means for rotating the drive shaft; 
     FIG. 6B is the second figure of said animation; 
     FIG. 6C is the third and last figure of said animation; 
     FIG. 7A is a front elevational view and the first figure of an animation depicting a novel control means for rotating the drive shaft; 
     FIG. 7B is the second figure of said animation; 
     FIG. 7C is the third and last figure of said animation; 
     FIG. 8A is a front elevational view and the first figure of an animation depicting a novel control means for rotating the drive shaft; 
     FIG. 8B is the second and last figure of said animation; and 
     FIG. 9 is a perspective view depicting a curved section of the novel conveyance means. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring initially to FIG. 1, it will there be seen that the reference number  10  denotes a prior art embodiment that will be described to better illustrate the need for an improvement in the means for changing the lateral spacing between guide rails. 
     The prior art conveyor,apparatus having adjustable guide rails includes a hand-rotatable knob  12  that is keyed to shaft  14 . An aperture is formed in frame extension  16  to receive said shaft. A drive gear  18  is mounted to the distal end of shaft  14  and said gear  18  is in meshing engagement with control gear  20  that is keyed for conjoint rotation to longitudinally disposed drive shaft  22 . A bore is formed in mounting block  24  to accommodate said drive shaft  22 . Accordingly, manual rotation of knob  12  in a clockwise direction effects clockwise rotation of longitudinal shaft  22  and manual rotation of knob  12  in a counterclockwise direction effects rotation of drive shaft  22  in a counterclockwise direction. 
     Pinion gear  26  is also keyed to drive shaft  22  for conjoint rotation therewith; it is longitudinally spaced from gear  20  as depicted. Rack gear  28  is formed in a first or upward-facing side of transverse rod  30  and rack gear  32  is formed in a second or downward-facing side of transverse rod  34 . Rack gears  28  and  32  respectively engage pinion gear  25  in diametrically opposing relation to one another when the novel assembly is in its assembled configuration. Accordingly, clockwise rotation of knob  12  effects clockwise rotation of pinion gear  26 . Both rack gears  30  and  34  are thus displaced in converging relation to one another, i.e., in the respective directions of arrows  31  and  35 , respectively. Counterclockwise rotation of said knob  12  effects counterclockwise rotation of pinion gear  26  and displacement of rods  30 ,  34  in diverging relation to one another, i.e., in the respective directions indicated by arrows  29  and  33 . 
     This converging and diverging of rods  30  and  34  results in reducing and increasing the space between guide rails  40  and  42 , respectively, because said guide rails are rigidly connected to upstanding rail supports  44  and  46 . Pins  43  and  45  secure the respective lowermost ends of said rail supports  44 ,  46 , to the outboard ends of rods  30  and  34 . 
     More particularly, pins  45  and  47  respectively secure the uppermost ends of rail supports  44 ,  46  to guide rails  40 ,  42 . Each rail support  44 ,  46  has a vertically-extending slot  49 ,  51  formed therein to allow height adjustability of said guide rails and a bushing  53 ,  55  is positioned between the uppermost end of each rail support and its associated guide rail as depicted. 
     Guide rails  40 ,  42  may be of any length. Accordingly, the same rack and pinion structure just described is provided along the longitudinal extent of a conveyor apparatus at predetermined longitudinal intervals. The parts in FIG. 1 that correspond to the just-described parts are denoted by the same reference numeral having the letter “a” appended thereto. 
     The remaining parts depicted in FIG. 1 are industry standard conveyor parts. For example, the reference numeral  60  denotes a conveyor belt made of individual parts as depicted but the construction has utility in connection with conveyor means of any type, including air-jet conveyor means having no belt. Vertical frames  62 ,  64  are also of conventional design, modified as needed to facilitate attachment thereto of the novel parts. Mounting blocks  66 ,  68  are mounted on the respective inboard sides of frames  62 ,  64  to provide support for rods  30  and  34  and are secured by pins collectively denoted  67 . 
     It is worth noting that the novel apparatus can be used to change the position of only one guide rail in those situations, such as on timing screws, where two guide rails are not needed. 
     FIG. 2 provides an assembled view of the rack and pinion assembly. The only reference numeral in FIG. 2 that does not appear in FIG. 1 is reference numeral  11  which collectively designates wiper seals at each location where rack gears  30  and  34  extend through frames  62  and  64 . 
     In the alternative prior art embodiment of FIG. 3, the output shaft of reversible motor  70  is secured for conjoint rotation to drive shaft  22 . Motor  70  is of the reversible type to enable clockwise and counterclockwise of said shaft  22 . In this way, motor  70  replaces knob  12 , shaft  22 , and gear  20  of the first embodiment. 
     FIG. 4 provides a perspective view of the prior art apparatus when a curve is formed in the conveyor apparatus. The structure is substantially the same as in the above-described embodiments where the conveyor is straight, with the exception that a section of guide rails  40 ,  42  (only one of which is depicted to simplify the drawing) and frames  62 ,  64  are curved. The rack and pinion-based structure for positioning the guide rails is not changed. Note that expansion slots  42   a  are formed in the respective ends of the guide rail sections adjacent to the curve and that the curved section of guide rail  42  has a tongue  42   b  protruding from each of its ends for sliding reception within said slots  42   a.  The respective lengths of the tongue and slots is sufficient to enable the tongues to remain within their respective slots as the distance between the guide rails  40 ,  42  is varied by the rack and pinion arrangement described above. 
     FIGS. 5A,  5 B, and  5 C are the first figures of this disclosure that relate directly to the present invention. Said figures depict a means for alternately moving guide rails  40 ,  42  toward and away from one another that does not include the above-described rack and pinion arrangement. Moreover, as will be understood in connection with FIGS. 6A-C, this novel embodiment does not require use of control knob  12  or motor  70 . 
     More particularly, this embodiment employs drive shaft  22   a  and said shaft can be rotated clockwise and counterclockwise as in the preceding embodiments by any suitable means such as manually rotatable control knob  12  and related assembly or reversible motor  70 , although such manipulation means are not the preferred means as aforesaid. Instead of having a circular cross-section, drive shaft  22   a  has a non-circular cross section to thereby facilitate its connection to center link  80 . Center link  80  is keyed to drive shaft  22   a  for conjoint rotation therewith and is pivotally connected at its opposite or outboard ends as at  81 ,  83  to first and second links  82 ,  84 . Said first and second links are pivotally connected at their respective outermost or outboard ends as at  85 ,  87  to mounting blocks  86 ,  88 , respectively. Mounting blocks  86 ,  88  are slideably mounted upon upper and lower rods  90 ,  92 . It should therefore be understood that prior art rail supports  44 ,  46  and hence prior art guide rails  40 ,  42  are mounted to said mounting blocks  86 ,  88 , respectively. 
     Accordingly, when center link  80  is positioned as depicted in FIG. 5A, guide rails  40 ,  42  are spaced apart from one another by a distance that is almost their maximum distance; all three links would lie in a horizontal straight line at said maximum distance. Clockwise rotation of drive shaft  22   a  over a sixty degree or so angle brings center link  80  to its FIG. 5B position; this represents an intermediate spacing for guide rails  40 ,  42 . Further rotation of about another thirty degrees in the clockwise direction brings the links to their FIG. 5C position; this position is the position where guide rails  40 ,  42  are at their closest spacing relative to one another. 
     FIGS. 5D,  5 E, and  5 F respectively provide a top, front, and an end view that further reveal the preferred structure of this embodiment. Links  80 ,  92  and  84  are collectively in a horizontal plane in these Figures, representing their respective positions when guide rails  40 ,  42 , not depicted, are at their maximum spacing with respect to one another. Upstanding elements  94 ,  96  are a part of a conventional conveyor frame. Center blocks  98   a ,  98   b  are mounted on longitudinal shaft  22   a  and are spaced from one another by pivot yoke  99 . Center blocks  98   a ,  98   b , and pivot yoke  99  are supports and thus perform the same function as pillow blocks. 
     As mentioned earlier, rotation of drive shaft  22   a  may be under the control of a manual knob, a reversible motor, or other suitable prior art control means. FIGS. 6A,  6 B, and  6 C depict a novel manually operable means for accomplishing rotation of said drive shaft  22   a . This embodiment includes an elongate crank arm  100  having a free end  102  that is grasped by a machine operator when it is desired to change the spacing between guide rails  40 ,  42 . Crank arm  100  is pivotally connected as at  104  to bell crank  106  having a drive shaft engaging first end and a second end that is angularly disposed with respect to the first. 
     Beginning in the position of FIG. 6A, the machine operator pushes crank arm  100  in the direction indicated by single-headed directional arrow  103 . Such motion causes drive shaft  22   a  to rotate about its axis of rotation in a clockwise direction until the position of FIG. 6B is reached. If it is desired to reduce the distance between the guide rails even more, crank arm  100  is again pushed, in the direction of arrow  105 , until it attains the position of FIG. 6C, which final position represents the closest possible spacing of the guide rails. Note that center link  80  in FIG. 6C is in substantially the same position as center link  80  in FIG.  5 C. Crank arm  100  is simply moved in the opposite direction to increase the spacing between the guide rails. 
     Free end  102  of control arm  100  may be pivotally and slideably connected as at  108  to a straight, elongate rail  110 . 
     There are an infinite number of positions of functional adjustment between the closest and the furthest spacing of the guide rails. An operator can push or pull on crank arm  100  and thereby reposition the guide rails as needed much faster than when using a control knob or a motor that rotates drive shaft  22   a.  Moreover, the operator can see the instantaneous response of the guide rails so fine adjustments are easy to make. 
     One drawback of the adjustment means of FIGS. 6A-C is that it is not easily lockable. Thus, to maintain a selected rail spacing, an operator must continue to hold crank arm  100  or must rig up something to hold control arm  100  in place when it is not manually held. 
     This problem is solved by the embodiments of FIGS. 7A,  7 B,  7 C and FIGS. 8A and 8B. An elongate screw actuator  112  is employed in the embodiment of FIGS. 7A-C, said screw actuator being pivotally secured to the free end of control arm  100  at pivot point  108 . The guide rails are at their narrowest spacing when control arm  100  is in its FIG. 7A position and at an intermediate spacing when said control arm is in its FIG. 7C position. The FIG. 7B position provides a spacing less than said intermediate spacing. There are an infinite number of spacings between the narrowest and broadest spacings. Including a worm gear, screw actuator  112  is substantially self-lockable. 
     The embodiment of FIGS. 8A and 8B includes a pneumatic cylinder  114  having an actuator  116  pivotally connected as at  108  to the distal free end of control arm  100 . The guide rails are at their narrowest spacing when actuator  116  is filly extended as depicted in FIG.  8 A and at their broadest spacing when said actuator is filly retracted as depicted in FIG.  8 B. Control arm is clearly lockable into either of said maximum and minimum positions but there are no intermediate positions. 
     FIG. 9 provides a perspective view of a curved section of the novel conveyance means. It should be understood that changing the spacing between guide rails  40 ,  42  necessitates changing the length of the curved sections, i.e., the curved sections have their greatest extent when said guide rails are at a maximum spacing and their least extent when said guide rails are at a minimum spacing. The novel means for accomplishing this change in length includes straight guide rail extensions  40   a ,  40   b  and  42   a ,  42   b  that are respectively slideably secured to opposite ends of curved guide rail sections  40  and  42 . A stop block  40   c ,  40   d  is respectively fixedly secured to each extension  40   a ,  40   b  and a stop block  42   c ,  42   d  is respectively fixedly secured to each extension  42   a ,  42   b  as depicted. Curved guide rails  40 ,  42  are axially bored to respectively slideably receive rods  40   e ,  40   f  and  42   e ,  42   f  that are respectively secured to said stop blocks  40   c ,  40   d  and  42   c ,  42   d . In this way, the effective length of curved guide rail  40  is lengthened by displacing extensions  40   a ,  40   b  in the direction of arrows  120  and said effective length is shortened by displacing said extensions in the opposite direction. Similarly, the effective length of curved guide rail  42  is shortened by displacing extensions  42   a ,  42   b  in the direction of arrows  122  and said effective length is lengthened by displacing said extensions in the opposite direction. 
     The novel linkage is free of gears and motors. It does not require frequent maintenance or adjustment and thus reduces conveyor system downtime. The spacing between the guide rails can be changed quickly and easily, in both straight and curved sections thereof. It has utility with all types of conveyance systems, whether of the belt, gravity, or air type. It also has utility in connection with machines or tools other than conveyance systems. 
     It will be seen that the objects set forth above, and those made apparent from the foregoing description, are efficiently attained. Since certain changes may be made in the above construction without departing from the scope of the invention, it is intended that all matters contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. 
     It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween. 
     Now that the invention has been described.