PLASTIC MONORAIL CONVEYOR DRIVE CHAIN LINKAGE

Abstract: A plastic one-piece conveyor drive chain link (40). The link embodies a plastic body (42) having lateral outwardly projecting flanges (44, 46) on each side of the body, upper and lower projections (52, 54) at the distal and proximal ends respectively of the body, and an upstanding locking lug (58) at its proximal end for removable articulated connection and engagement of each link with the next to form an endless drive chain for a conveyor system. The plastic linkage requires no lubrication, is quiet in operation and, because of lower weight, requires considerably less energy for its actuation and movement than is necessary for currently conventional steel monorail conveyor drive chain systems. Preferred embodiments of the invention also include chain links having a lateral outwardly projecting flange or spoke (154) on only one side of the chain link body instead of on both sides, depending upon the direction(s) taken by the monorail conveyor system, and one or more vertical slots through the body to accommodate the locking lug (58), which may be vertically upwardly or downwardly applied, and the pendant of the monorail conveyor trolley.

Description: PLASTIC MONORAIL CONVEYOR DRIVE CHAIN LINKAGE Background of the Invention This invention relates to a monorail conveyor drive chain. Monorail conveyor systems in the past have been made primarily of steel components suspended from steel supporting members welded to the building superstructure, the monorail track comprising continu¬ ous lengths of I-beam welded together in a series at their ends. The monorail system has included steel conveyor trolleys movable upon the I-beam monorail track by steel-driven chain linkage engageable with the trolleys. This type of monorail conveyor system has been in operation for many, many years with little, if any, modification. Problems attending such prior art steel monorail conveyor systems have included high initial material and installation costs, high maintenance and repair costs, high noise pollution, and a lack of color coding for safety and identification purposes. Because the principal components of steel monorail conveyor sys¬ tems must be welded together, skilled workmen at high hourly rates are required to make these installations. Also skilled tradesmen are required to assemble this equipment and install the same from supporting super- structure. Maintenance costs are high because these same skilled workmen are required to replace or repair damaged components or portions thereof. Since paint SUBSTITUTE SHEET or exterior finishes adhere very poorly to steel sur¬ faces located at and operating in areas and atmos¬ pheres having a relatively oily or chemical vapor content, it is practically impossible to maintain a color on the monorail conveyor components which would function as a signal that such apparatus is present and that there may be danger to personnel in its area . of operation. The lack or failure of color coding monorail equipment also constitutes an insufficiency in identification of the components which are or can be carried by the system. The high decible noise quotient common to steel driven monorail conveyor sys¬ tems results in major part from the difficulty in welding sections of the monorail in a level attachment of the trolley-riding I-beam surfaces and in the drive engagement of the steel drive chains upon steel trolleys, so that a loud σlickety-clack occurs each time a trolley rides across the juncture of the mono¬ rail I-beam and as the drive chain links engage and disengage from pendant portions of the trolleys. Where hundreds of such junctures and trolleys are present, the conveyor noise is, in some instances, highly dis¬ comforting, substantially decreasing worker efficiency. Additionally, the steel drive chains are relatively difficult to service and maintain, the latter process including expensive installed equipment to lubricate the chain drive system, a cost avoided by the instant invention. Brief Summary of Invention This invention relates to a plastic monorail con¬ veyor drive chain. The component members of the drive chain are preferably made of a strong durable plastic material such for example, but not limited to, the BSTITUTE SHEET DuPont Zytel®ST nylon polyamide produced by the E. I. DuPont de Nemours and Company of Wilmington, Delaware. The conveyor trolleys of this invention are also preferably made of the Zytel®ST nylon material and/or of the Delrin® crystalline acetal resin material made by the polymerization of formaldehyde. Either of these materials can be mixed with a fiberglass concen¬ trate to add further strength to the plastic resin. The amount of such fiberglass additive is proportional to the weight load of the conveyor trolleys, the parts to be carried thereby, the monorail track and its supporting structural members. All of these factors are considered in the formulation of the plastic resin material used for fabrication of the drive chain link- age. As the load or weight requirements of these com¬ ponents increase, the percentage of fiberglass used with the resin material may also be increased. The coefficient of friction of the plastic materi¬ als used in the inverted T-bar shaped monorail track and the plastic trolleys is extremely low, therefore, lubrication of moving parts such as the drive chain of this invention, when in contact and driving engagement with the conveyor trolleys, is not required. This feature alone eliminates considerable expensive lubri- cation material, service facilities, installation and maintenance. Removal of lubricants from the site substantially eliminates one major source of contamin¬ ants dripping upon fresh or processed foods carried by or located under the conveyor system in food processing plants. The weight reduction in the use of plastic conveyor supporting members, an inverted plastic T-bar shaped monorail track and the plastic trolleys is of the order of about 80% less than is present in the I-beam and OMPI trolleys of a steel conveyor system. Such weight reduction not only extends the life of the monorail conveyor track itself but also the service life of the entire conveyor system. The weight reduction lowers significantly the size and capacity of drive motors and drive mechanism including the drive chain, with consequent significant reduction in energy consumption. The plastic monorail conveyor track, plastic trol¬ leys and the plastic drive chain of this invention are extremely advantageous in areas where severly corros¬ ive chemical vapors are present and where caustic wash solutions are sprayed. These corrosive chemicals cause a breakdown in the lubrication system of steel conveyor systems, in turn destroying the roller bear- ing assemblies of the trolleys and interfering signi¬ ficantly with effective operation of steel conveyor drive chains. The corrosion occuring in the steel monorail track itself further contributes to early conveyor failure and consequent high maintenance, repair and replacement costs. The plastic T-shaped monorail track, the plastic trolleys and the plastic conveyor drive chain of this invention permit lower replacement costs for these components, and much easier service if repair is required. Installation of the equipment is made with conventional fasteners such as bolts, washers and nuts, by relatively unskilled labor at much lower costs in comparison with that required for a steel conveyor system. Removal of defective or failing parts is quickly and easily made by such relatively unskilled labor, reducing downtime for the plastic conveyor sys¬ tem. The plastic conveyor drive chain of this inven¬ tion does not utilize any metal components or elements and is easily and quickly assembled by unit link mem¬ bers which can be installed and replaced as needed by relatively unskilled labor. The plastic T-bar monorail track, plastic trolleys and plastic drive chain of this invention effect a tremendous reduction in decibel readings in the con¬ veyor zone, a significant advantage in terms of noise abatement and/or pollution. Because the plastic resin materials allow for the engineering and production of precision components and assemblies thereof, secondary drilling of holes or alignment of details are unnecessary prior to con¬ necting the drive chain link members together and mounting them upon the pendant members of the plastic trolleys. Color coding of the plastic drive chain links, as well as of the plastic trolley assemblies and monorail sections, enable parts identification to be more readily made, particularly on mixed model conveyor sys- terns. Such color coding of the T-bar monorail track, the plastic trolleys and the plastic conveyor drive chain linkage, particularly in bright colors, signals the presence of moving objects and provides a greater measure of safety to personnel in the operation of the plastic monorail conveyor system. A significant improvement over the conventional 3-piece steel drive chain linkage is the one-piece plastic chain link of this invention. Not only are fewer parts required, but the unitary molded plastic links are identical, can be assembled in chain arrange¬ ment in only one manner, and will function efficiently with much lower drive energy and less expensive power drive equipment. SUBSTITUTE SHEET IfUREA OMPI f WWIIPPOO A single locking lug of one link engages and con¬ nects the next adjacent chain link during the drive function. The links each have laterally extending male projections to engage power driven notched or slotted drive wheels (in contrast with spoke-type sprockets) , so that the chain links can turn to the left or right, and move vertically upward or downward. Single element chain links are more easily stored and dispensed, inventory controlled, and replenished by production, requiring no assembly in the field, only attachment by connection at a single member, the lock¬ ing lug. Brief Description of Drawings Various further and more specific objects, features and advantages of the invention will appear from the description given below, taken in connection with the accompanying drawings, illustrating by way of example a preferred form of the invention. Reference is here made to the drawings annexed hereto forming an integral part of this specification. Figure 1 is a front elevational view of a straight portion of a plastic monorail conveyor structure show¬ ing a plastic inverted T-bar shaped monorail track, plastic trolleys suspended from the track with an engaged plastic drive chain embodying the invention, and pendant parts hangers attached to the trolleys. Figure 2 is a top plan view, partially in section with respect to the engaged trolleys, of a portion of the drive chain, taken substantially on the line 2-2 of Figure 1. Figure 3 is a front elevational view of the drive chain portion illustrated in Figure 2. SUBSTITUTE SHEET - REA OMPI WIPO Figure 4 is a vertical transverse sectional view taken substantially on the line 4-4 of Figure 2. Figure 5 is a perspective view of a portion of the conveyor and an idler wheel rotated by the drive chain linkage illustrated in the foregoing views. Figure 6 is a bottom plan view, partially in sec¬ tion, of the chain driven idler wheel illustrated in Figure 5. Figure 7 is a transverse vertical sectional view taken substantially on the line 7-7 of Figure 6. Figure 8 is a perspective view of the unitary molded plastic drive chain link embodying the inven¬ tion. Figure 9 is a vertical elevational view, partially in section through a portion of the conveyor monorail and the drive chain linkage, one side of the engaged conveyor trolley being shown substantially in ele¬ vation. Figure 10 is a perspective view of a modified form of the plastic drive chain link illustrated in Figures 1-9, but having only a single lateral spoke or flange. Figure 11 is a perspective view of another modi¬ fied form of a plastic conveyor drive chain linkage. Figure 12 is a top plan view of the plastic drive chain linkage illustrated in Figure 11. Figure 13 is a side elevational view. . of the engaged plastic drive chain linkage illustrated in Figure 11. Figure 14 is an end elevational view of the plastic drive chain link illustrated in Figure 11. Figure 15 is a perspective view of two plastic drive chain links, as illustrated in Figure 11, showing their relative attitudes prior to linking engagement. Figure 16 is a perspective view of a modified form of the plastic conveyor drive chain link illustrated SUBSTITUTE : :EET in Figure 11. Description of the Preferred Embodiment A preferred embodiment of the invention is illus¬ trated in the several drawings forming an integral part of this specification. The plastic monorail conveyor structure 10 can be suspended from steel roof trusses (not shown) by plas¬ tic or metal supporting angle and channel members 18 and 20 respectively and plastic bracket members 22 con- nected to the inverted T-bar shaped monorail track 30 by conventional fasteners 24, such for example as bolts, washers and nuts. The plastic monorail conveyor structure 10 com¬ prises a plurality of connected longitudinally extend- ing inverted plastic T-bar monorail track sections 30, the plastic conveyor trolleys 32 operatively translated thereon, and the plastic drive chain 34 operatively engaged with the trolleys 32. The construction of the plastic monorail track 30 and the plastic conveyor trolleys 32 are fully dis¬ closed in my co-pending applications Serial Numbers and , filed , 1982 entitled "Plastic Monorail Conveyor Structure" and "Plastic Monorail Conveyor Trolley". The plastic drive chain 34 comprises a plurality of integrally formed, unitary, molded plastic chain links 40, each comprising a body portion 42, a pair of lateral outwardly projecting oppositely directed spokes or flanges 44, 46 lying in a plane and substantially medially vertically and horizontally of the body 42, a pair of longitudinally aligned vertical slots 48, 50 through the body 42, an elevated projection 52 at the SUBSTITUTE SHEET ( IPnO distal end of the body, a lowered projection 54 at the proximal end of the body, and an upstanding stem 56 crowned by a horizontal transversely disposed locking lug 58 supported on the lower projection 54. The chain links 40 are articulatedly connected together by inserting the locking lug 58 upwardly through the slot 48 until the lug extends above the body projection 52, then rotating the link body 90° until the lug 58 is transversely of and above the slot and projection. This engagement is sufficient to con¬ nect each link serially with the next. The chain links 40 are engaged with the trolleys 32 in the following manner. The trolley arms 72,72 are secured together by fasteners 74 at the lower depending portions 80,80 and through the lower wheels 76,76 which pass or ride under the T-bar monorail flanges 78,78. The depending flanges 80 secure the upper proximal portion 82 of the pendant 84 (Figure 9) by the fastener 74, the body portion 86 depending from the flanges 80 and fastener 74. A pair of lateral substantially horizontal outwardly projecting flanges 88,88 define a lower limit and provide a rest for the chain link body 42, the pendant body portion 86 extend¬ ing through the slot 50 of the link. The pendant lower portion 90 adjacent and extending below the flanges 88,88 has a transverse opening 92 therethrough for reception of a fastener to secure a parts hanger 94 therefrom therebelow. Figures 5, 6 and 7 illustrate an idler driven or drive wheel 110 mounted by brackets 112 and supporting members 114 for rotation in the plane of the drive chain 34 about a turn in the conveyor or at the power drive position of the conveyor structure. The wheel 110 comprises a plurality of pockets 116 spaced radially SUBSTITUTE £ _E T fe OMP Ϊ apart from each other, each being defined by an inner wall 118, side walls 120, a connecting outer wall 122 enclosed by upper and lower walls 124,126 respectively, and arranged generally in a serpentine manner at the peripheral edge of the wheel. The inner dimensions of the pockets 116 are such as to accommodate and receive the outer dimensions of the link flanges 44,46 within the arc of travel as the links 40 engage the wheel 110. As shown more particularly in Figures 6 and 7, the body of the wheel 110 comprises an outer annular ring 130 containing the pockets 116 and having a medial annular web portion 132 with upper and lower radial stiffening ribs 134 connected to a hub portion 136 with an inner annular flange 138. The body of the wheel further comprises a central hub 140 having an outer annular flange 142 adapted to seat upon and be connected by fasteners 144 to the inner annular flange 138, the hub 140 being rotatable upon a shaft 146 supported by the structural members 112 and 114, or the hub is fixedly mounted on a drive shaft at the power drive position of the conveyor system. A modified form of the chain link 40 is illustrated in Figure 10, wherein the link 40a is provided with a single laterally outwardly projecting spoke or flange 44, the opposite side of the link body 42 being sub¬ stantially flat and planar. Another form of the chain linkage, and also a preferred form, is that illustrated in Figures 11 through 16, inclusive. The chain link member 150 com- prises a body 152, a laterally outwardly projecting ' drive spoke or flange 154 (optionally, a second oppositely directed spoke 156 is shown in Figure 16) substantially medially vertically and horizontally of the body 152, a single longitudinally extending SUBSTITUTE SHEET OMPI vertical slot 158 substantially medially through the body 152, an elevated projection 160 at the proximal end of the body, a lower rearwardly projecting end portion 162 at the distal end of the body, and a stem 164 depending from the elevated projection 160 and terminating in a horizontal transversely disposed flanged locking lug 166 at the lower end of the stem and lying in a plane below the bottom surface 168 of the body 152. The upper surface 170 of the body is angled downwardly from the elevated projection 160 to the lower proximal end portion 162. When the chain links 40, 40a or 150 have been serially connected and mounted upon the trolleys 32 and idler wheels 110, the power drive wheel is moved to a retracted position so that the endless chain of links 40 or 150 can be positioned upon the drive wheel as hereinabove described. The drive wheel is then re- positioned for a more positive engagement with the endless drive chain 34. Such engagement is conven- tional practice which eliminates the necessity for special closing locking links. The drive chain link members 40, 40a or 150 are each unitary, integrally formed, molded components fabricated of DuPont's Zytel® plastic or Delrin® plas- tic, or of other suitable equivalent materials. If necessary or desirable, the plastic material can be strengthened by the inclusion of fiberglass filaments, according to accepted practices in the plastic forming arts. Having disclosed certain particular preferred embodiments of the invention for purposes of explana¬ tion, further modifications or variations thereof, after study of this specification, will or may occur or SUBSTITUTE * ■ *■ -— P become apparent to persons skilled in the art to which the invention pertains. Reference should be had to the appended claims in determining the scope of the invention. SUBSTITUTE SHEET OMPI

Claims: CLAIMS 1. In a power actuated conveyor drive chain for engaging and translating a plurality of conveyor trol¬ leys operatively supported on a monorail track, the im¬ proved chain linkage comprising a plurality of plastic drive chain links articulatedly connected in an endless series, each said chain link being an integrally form¬ ed, molded, unitary plastic member comprising a body having a pair of aligned vertical slots therethrough; an upper forwardly projecting portion at its distal end and a lower rearwardly projecting portion at its proxi¬ mal end; a flange or spoke projecting outwardly from at least one lateral side of said body; and a crowned stem extending vertically from said lower rearwardly projecting portion; the crowned portion of said stem lying in a plane above said body; said crowned stem adapted to pass into and partially through one said slot of the next adjacent chain link body and rotate into engagement therewith; said second slot adapted to pass a portion of a trolley pendant therethrough. 2. The chain linkage defined in claim 1, wherein said crowned stem comprises an upstanding post and a locking lug or flange disposed transversely of and in a plane above said body; whereby when said crowned stem is inserted through said slot of the next adjacent link and rotated in the plane of said link bodies, said locking lug extends transversely of and beyond the lateral limits of said slot to engage said body there adjacent. 3. The chain linkage defined in claim 2, wherein said locking lug or flange comprises a planar member having a rectangular configuration in plan. SUBSTITUTE ev -T "' " ~ 4. The chain linkage defined in claim 2, wherein said slot adapted to receive and pass said locking lug therethrough comprises a rectangular passage in hori¬ zontal section through said body. 5. The chain linkage defined in claim 1, wherein said upper and lower projecting portions lie in the plane of said chain link body. 6. The chain linkage defined in claim 5, wherein said upper and lower projecting portions extend longi- tudinally and are aligned with said chain link body. 7. The chain linkage defined in claim 1, wherein said vertical slots are longitudinally aligned in and medially of said body and in a plane normal to the plane of translation of said linkage. 8. The chain linkage defined in claim 1, wherein said lateral flanges or spokes are disposed substan¬ tially medially horizontally and vertically of said chain link body. 9. The chain linkage defined in claim 1, wherein said one slot being located adjacent said upper for¬ wardly projecting portion of said chain link body, said second slot being located adjacent said lower rear¬ wardly projecting portion of said chain link body. 10. In a power actuated conveyor drive chain system for translating a plurality of chain link connected conveyor trolleys on a monorail track, an improved chain link-engaged turn wheel comprising an outer wheel rotatably actuated by said chain links having; a pocketed outer peripheral edge defined by a serpentine wall forming recesses therein adapted to receive and engage spokes or flanges extending laterally from said chain links. SUBSTITUTE SHEET OMPI W 11. The drive chain system defined in claim 10, wherein said turn wheel comprises a plastic outer wheel member; and a plastic hub member fixedly secured to said wheel member axially and central thereof; each said wheel and hub members being unitary, integrally formed and molded of a plastic material, said recesses being further defined by upper and lower walls adjacent said serpentine wall to form pockets in the peripheral edge of said turn wheel. 12. The drive chain system defined in claim 10, wherein said turn wheel is rotatable in the plane of said connected drive chain links. 13. The drive chain linkage defined in claim 1, wherein said body is provided with a flange or spoke projecting outwardly from each lateral side of said bod . 14. In a power. actuated conveyor drive chain for engaging and translating a plurality of conveyor trolleys operatively supported on a monorail track, the improved chain linkage comprising a plurality of plastic drive chain links articulatedly connected in an endless series; each said chain link being an integrally formed, molded, unitary plastic member comprising a body having; a longitudinally extending vertical slot substantially medially therethrough; an upper forwardly projecting portion at the proximal end of said body and a lower rearwardly projecting portion at the distal end of said body; a drive spoke or flange projecting outwardly from at least one lateral side of said body, and a lug-crowned stem extending vertically downwardly from said upper forward¬ ly projecting portion; said lug-crowned stem adapted to pass into and partially through said slot of the next adjacent chain link body for rotational engagement SUBSTITUTE SHEET therewith; said slot adapted to pass a portion of a trolley pendant therethrough. 15. The drive chain linkage defined in claim 14, wherein said body is provided with a flange or spoke projecting outwardly from each lateral side of said body. 16. The drive chain linkage defined in claim 14, wherein said lug-crowned stem comprises a depending post, and a locking lug or flange disposed trans- versely of and in a plane below said body; whereby when said lug-crowned stem is inserted into and partially through said slot and rotated in the plane of said chain link bodies, said locking lug extends transversely of and beyond the lateral limits of said slot to engage said body there adjacent. 17. The drive chain linkage defined in claim 16, wherein said locking lug or flange comprises a planar member having a rectangular configuration in plan. 18. The drive chain linkage defined in claim 16, wherein said slot adapted to receive and pass said locking lug therethrough comprises a rectangular passage in horizontal section through said body. 19. The chain linkage defined in claim 14, wherein said upper and lower projecting portions lie in the plane of said chain link body. 20. The chain linkage defined in claim 19, wherein said upper and lower projecting portions extend longi¬ tudinally and are aligned with said chain link body. 21. The chain linkage defined in claims 14 and 15, wherein said lateral flange or flanges are disposed substantially medially horizontally and vertically of said chain link body. SUBSTITUTE SHEET 22. The chain linkage defined in claims 1 and 14, wherein said stem is substantially cylindrical in cross-sectional configuration. 23. The chain linkage defined in claim 3, wherein said locking lug has a width less than and a length greater than the width of said one slot. S _T"U_ .ir.-IS*-i'"I_"i* s, U1 I"*<"(:-_. S tr".T_ϋ_"_"."_-_.T!

Inventors: FORSHEE DAVID J, FORSHEE, DAVID, J.
Applicants: FORSHEE DAVID J, FORSHEE, DAVID, J.
Application year: 1983
Main classification: B65G17
IPC codes: B65G17, B65G23