FR2711933A1 - Accumulation stores (magazine), especially for a manufacturing or machining line, for feeding a workstation with workpieces or with tools... - Google Patents

Abstract

a) Accumulation stores (magazine), especially for a manufacturing or machining line, for feeding a workstation with workpieces or with tools..., b) characterised in that: A) Each shuttle (5) has a running member (36) driven in rotation by the associated sprocket (28) of the shuttle (5), B) The end return (8, 9) of each chain (line) (16) (16B) comprises: - a sprocket (40) over which the chain (16) (16B) passes, - in the path of the running members (36) of the shuttles (5), a return disc (42) coaxial with the return sprocket (42) and free to rotate, a return guide (43, 43B) in the shape of a circular arc partially surrounding the return disc (42).

Description

"Accumulation store, especially for a manufacturing or machining chain, to supply a workstation with parts or tools ..."
The present invention relates to a storage magazine for supplying work stations, a magazine comprising - two endless, parallel drive chains,
traveling in synchronism passing over references
end wheel drive and den wheels
free tees, - guide and support rails, - a set of toothed pinion shuttles
ment and load-bearing rollers, the toothed gears generate
with chains to drive shuttles,
their rollers rolling on the guide rails and
support, - retractable stops defining the positions
shuttle stop.

 There are different transfer machines having an accumulation function, that is to say receiving products for distributing them in a controlled manner according to a predetermined sequence or orders supplied by a control means.

 There are storage stores with conveyor belts or belts. Although inexpensive to manufacture, these stores nevertheless have a certain number of drawbacks which do not allow their use in sites requiring precise transfer of products (parts, tools, etc.).

 The conveyors generally used in such situations are conveyors with two parallel chains passing at the head of the conveyor on a double toothed drive wheel and at the tail of the conveyor on a double toothed return wheel. These chains carry in their circuit supports called shuttles receiving the trays themselves carrying the products to be transferred. These products to be transferred are generally positioned precisely on the trays themselves positioned precisely on the shuttles because they are integral and ready on the shuttles.

 The shuttles are not integral with the chains but driven by pinions, the shuttles being guided in their movement by a rectilinear rail in its part corresponding to the upper strand and to the lower strand of the conveyor and a curved rail around the ends. On each side the shuttle generally comprises two rollers rolling on the rails. The drive is done by toothed pinions integral with the axis of the rollers. These toothed gears mesh on each side of the magazine with the drive chain. When the shuttle is stopped by a stop or by shuttles which precede it in front of the stop, the toothed wheels are always driven by the chains but the rollers come to a standstill relative to the rail. As soon as the stop is retracted, the shuttle (s) can continue on their way.

 To ensure the trolleys drive down and up around each end of the conveyor, there is provided in parallel and around the drive gear and the free gear, a curved rack on which the shuttle sprockets also driven by chains.

 The shuttles are driven on the upper and lower rectilinear part of the conveyor by the pinions of the shuttles force-driven by the rotational movement of the two chains. However, this training only results in a displacement of the shuttles if they can rest on their rail and roll freely without being retained. Otherwise, the rollers come to rest on the rails.

 At the ends of the magazine, the drive cannot be disengaged in this way.

 I1 must be forced, so the known store has it parallel to the end idler gear, a curved rack, in which the pinions of the shuttles mesh. These pinions roll without sliding in the racks, being forced into this movement by the chains.

The main disadvantages of such storage magazines are - the precision required for setting the racks
end in relation to the drive wheels
and free, - compensation for the lengthening of the chains in
during operation.

- the realization of curved racks, precise and
therefore expensive and which must be glued exact
in pairs at each end of the return.

- all drive and return means
requires precise timing of the gear wheels,
rack and pinion chains as well
that a joining of the homologous sprockets of cha
that shuttle.

- the extension of the installation as a result of the setting
in tension, this elongation being able to reach a
ten centimeters.

 However, the slightest offset due to a different elongation of the two chains results in an imbalance of the forces and movements, particularly perceptible in the return zones, on the path of the pinions on the racks.

 The effect of wear is reflected in an avalanche effect which accentuates more and more the imbalance of forces exerted on the two chains.

 To compensate for this inevitable elongation, the axis of the toothed wheels of one end of the magazine is mounted on a moving mobile in translation bearing on the frame of the magazine by means of two tensioning screws used for adjusting the chains, c ' that is to say the compensation for the elongation. They must be re-tightened with these two screws, making sure that the axis of the two cogwheels moves in strict parallelism because the two chains must remain perfectly wedged against each other.

 These compensation adjustments should be very frequent, but this is not materially possible since the workstation or even part of the production line must be stopped.

 Although for the reasons explained above it is necessary to use two paired chains, that is to say whose links at any point of the chain correspond exactly, the wear and the long air of these two chains is inevitably different. However, the tension of the chains can only be done by parallel displacement of one of the axes of the return gear wheels, necessarily one chain will be more taut than the other and will be subjected to greater efforts. It will very quickly result in a new adjustment.

 In summary, such storage magazines generally work properly for a few months, then the first tension adjustments must be made; wear and elongation accelerating, these interventions become more and more frequent so that the duration of operation and use of such a store is currently short without incident.

 In other words, the very rapid wear of the chains (initially paired) also results in an irregular wear of the toothed wheels, especially of the drive wheels so that to the replacement of the chains it is necessary to add the practically essential replacement of these wheels toothed and even racks.

 The present invention aims to remedy these drawbacks and proposes to create a storage store with a simple structure, retaining a constant center distance, using unpaired chains, allowing reliable operation, without frequent maintenance interventions, having silent operation and usable without transformation both as a ground transporter and an air transporter.

To this end, the invention relates to an accumulation store corresponding to the type defined above, characterized in that
A) Each shuttle (5) has a rolling member
(36) rotated by the toothed pinion (28)
associated, of the shuttle (5),
B) The end gear (8, 9) of each chain
(16), (16B) includes
- a toothed wheel (40) over which the chain passes
(16), (16B),
- on the path of the running gear (36)
shuttles (5), a return disc (42),
coaxial with the idler gear (42) and free
in rotation, a return guide (43, 43B) in for
me of a circular arc partially surrounding the
deflection disc (42) for defining therewith
a radial width drive path (B)
slightly smaller than the diameter (D) of the organs
bearing (36) thereby forming a path for
these rolling bodies,
C) Toothed pine nuts (28) on each side of the turnip
te (5) are independent,
D) A loop tensioner (12) is provided independently
for each chain (16), (16B) to apply it
a determined tension and compensate for its extension
is lying.

 According to a particularly advantageous embodiment, the rolling members are shoulders of the axes of shuttles.

 At the end deflection wheel, the curved guide, fixed, and the disc opposite this guide forming between them an interval slightly less than the diameter of the shoulders of the axes, drive the shoulders of the axes while the pinions continue to '' mesh with the chain rotating on the wheel. The shoulder is forced to roll without friction on the outer fixed curved guide while its diametrically opposite side is pressed against the smooth disc and rotates it by a rolling movement.

 The disc which rotates at the same peripheral speed as the shoulder of the axes has an external diameter chosen according to the axis and the diameter of the shoulder as well as the diameter of the toothed wheel (coaxial) and that of the pinion of the shuttle so that this pinion does not rest on the chain allowing it to function normally, without driving it in between the teeth of the wheel. The chain thus continues to play its driving function (and not of support) even in the curved parts of the path.

 The absence of chain chains results in no malfunction and even an inevitable different lengthening of the chains does not hamper the operation of the store. The extension of each chain being absorbed by an independent tensioner, the chains will always be maintained at a constant, identical tension. This results in a variable setting of the chains along their course, except at the level of the toothed wheels because at this point the chains are at least approximately wedged one on the other by these toothed wheels. However, this lack of correspondence between the position of the links of the two chains has no repercussions on the drive of the shuttles whose homologous pinions are independent in rotation and no longer integral with the same axis.

 This operating mode ensures a slip-free drive both when the shuttles are lowered and when they are raised to the upper strand. In addition, it allows to associate with each chain a loop tensioner interrupting the path normally followed by the pinions of the shuttles for a certain distance less than the center distance of the shuttle. This interruption does not block the drive of the shuttles or the engagement of the pinions since the shuttles can have two drive pinions on each side.

 As moreover the axes of the shuttles are not integral in rotation, each pinion can at any moment be driven at a different speed from the corresponding pinion on the other side of the shuttle. The tensioner, for example by an air spring, for each of the two chains, can be placed anywhere on the path of the shuttles. Each tensioner ensures permanent continuous tension in each chain, directly compensating for any wear or lengthening. In addition, it is no longer necessary to wedge one on the other the two chains except for a certain "natural" wedging in line with the drive and return wheels at each end of the conveyor.

 The tension of each chain is independent so that whatever the difference in elongation each of the two chains will always be tensioned at the set force provided by the tensioner.

 As the sprockets on each side of the shuttles are independent, the storage magazine can use unpaired chains.

The present invention will be described below in more detail with the aid of the accompanying drawings in which
- Figure 1 is a side view of an accumulation store according to the invention.

 - Figure 2 is a top view of the store of Figure 1.

 - Figure 3 is a half-section of the store of Figures 1 and 2.

 - Figure 4 is a schematic view of an end gear of the magazine.

 - Figure 5 shows an embodiment of a tensioner.

 - Figure 6 shows a detail of a shuttle to the right of a retractable stop of the store.

 - Figures 7 and 8 respectively show a left view and a top view of a portion of a shuttle and the retractable stop of the store.

 - Figure 9 shows the hitch connecting two shuttles to form a train of shuttles.

 According to Figures 1 and 2, an accumulation store according to the invention is a conveyor intended to transport shuttles between at least one entry station and one exit station with possibly intermediate stations.

This store consists of two side parts, symmetrical 1, 2 each having an endless chain, driven, as well as guide paths for the shuttles. These two parts are connected by crosspieces 3 carried by feet 4. The spacing of feet 4 corresponds to the greatest width of the plates that receive the shuttles. The trays attached to one or more shuttles (shuttle train) are used to receive the products to be transported, in a precise position. These platforms must be able to circulate with the shuttles. While the width of the shuttles is less than the width of the magazine, that of the trays can be greater than this width. They must be able to pass between feet 4 on the return strand (Figure 2). Figure 1 shows shuttles
SA, 5B, isolated and an accumulation of shuttles 5C retained by the upstream shuttle 5D in the direction of travel (A).

 The two parts 1, 2 being symmetrical, the following description will be limited to one of the two parts (in particular in the section view of FIG. 3).

 Each lateral part 1, 2 consists of an upper strand 6, going strand, and a lower strand 7, return strand, connected at each end by end links 8, 9 constituted by toothed wheels. . The engine end gear 8 is fitted with a geared motor 10 fitted with an anti-torque damper 11. At the end gear 8 there is provided a loop tensioner 12 for each part 1, 2. The two tensioners are independent. They exert a constant, regulated tension and absorb the excess length of the chain by a loop, without modifying the overall course followed by the chain nor modifying the center distance of the end links 8, 9. An example of such a tensioner is shown in Figure 5.

 According to Figure 3, the side part 1 of the magazine consists of an upper beam 13 corresponding to the strand to go and a lower beam 14 for the return strand. These two beams are formed by a profile of the same section, for example aluminum. The sections 13, 14 constitute both the guide and drive path of the shuttles 5 carrying the plates 15. Via a chain 16, shown here in the form of a triple chain, the section 13 comprises at its lower part of the housings 17, 18 with longitudinal slots 19, 20 for the passage of the fixing bolts 21, 22 of the profile on a box 23 and on its vertical flange 24. This box 23 is connected to the counterpart box of the another part 2, by a spacer 25, the whole forming a single piece.

 Above the housings 17, 18 the profile comprises a recess 26, 26A open longitudinally, symmetrical, receiving on each side a plastic guide rail 27, 27A for the two outer links 16A, 16C of the chain 16; the inner link 16B remains free in the meantime.

 This internal link 16B is intended to cooperate with the teeth of the pinion 28 of the shuttle 5.

 Above the guide linings 27, 27A the profile has a housing 29 located on one side and which forms the raceway of the roller 30 associated with the pinion 28 of the shuttle 5. Finally, the upper part of the profile constitutes a housing 31 serving as a release. All of the housings 26, 29, 31 form a C-shaped structure with a wing 32 on the inner side, leaving a slot 33 free through which the shoulder 36 of the axis 34 of the pinion 28 and the roller 30 of the shuttle 5.

 The shuttle 5 is provided with four rollers 30 (see also FIG. 4). Each roller 30, associated with its drive pinion 28 has a friction connection represented by the axis 34 and the ring 35 because the shoulder 36 and the pinion 28 are integral and cannot move relative to one another. to the other (press fitting). This shoulder constitutes a rolling member integral in rotation with the pinion 28 and serving to drive the shuttle 5 to the end links 8, 9, as will be described later.

 This friction link ensures the transmission of the rotational movement communicated to the pinion 28 by the chain 16 while allowing the roller 30 to remain blocked and not to slip on its guide path when the shuttle 5 is blocked either by a stop or by other shuttles which precede it.

 Otherwise, there is no rotational movement of the pinion 28, the chain 16B pulls the pinion 28 which itself pulls the roller 30 mounted on ball bearing, which allows the roller 30 to roll in its path bearing, the axis 34 and the pinion 28 not rotating.

 The axis carrying the toothed pinion 28 and the roller 30 is housed in a smooth bearing 35 of the shuttle. This axis 34 can also be housed in another bearing or pass through the shuttle, knowing that the four pinions 28 of the shuttle are independent in rotation, as well as the four axes 34.

 FIG. 4 schematically shows the structure of a return end, for example the non-motorized return end 9. This figure shows different positions of a toothed pinion 28 and its shoulder 36, the toothed pinion 28 being only represented by a circle and the chain 16 by a line.

 The return end 9 consists of a return gear 40, simply represented by a circle with an axis 41. Coaxially, but free to rotate, this axis 41 carries a return disc 42 whose outer surface is smooth.

 In parallel, around the deflection disc 42, a guide 43 is provided, represented by a simple line in an arc 43A, surrounding the disc 42 on its left half (relative to the vertical axis YY) and extending to the 'entry by a line segment and at exit 43B by a line segment 43C.

 The circular arc segment 43A corresponds exactly to the disc 42 and forms therewith a drive path 44 of width B in the radial direction. This width B is slightly less than the diameter D of the shoulder 36 so that the shoulder 36 is slightly tightened by its drive path 44.

 As already indicated, the shoulder 36 constitutes an embodiment of a rolling member whose characteristic is to be driven in rotation by the toothed pinion 28 in particular by being integral in rotation with the latter.

 The drive path formed by the disc 42 and the circular arc 43A is located on the path of the rolling members 36 at the level of the end links 8, 9.

 The disc 42 and / or the guide track 43 are preferably made of a material having a certain flexibility, for example a plastic material, allowing a slight deformation in contact with the drive shoulder 36 of the raceway 43, the disc 42 does not deform.

At the level of the reference 9, the drive of the shuttle, that is to say the movement of the shoulder assembly 36 / toothed pinion 28, is done as follows
The teeth of the pinion 28 mesh with the chain 16 (16B) itself pulled in the drive direction A. The chain 16 thus rotates the pinion 28 around its axis in the direction of the arrow E. The pinion 28 drives in rotation the shoulder 36 of its axis 34 which rolls without sliding on the fixed guide 43A (especially in the curved part 43A).

 However, sliding is possible at any point of the curve and therefore causes the shuttle to stop following an external action, voluntary or not, on the shuttle. This is important for the safety of the system and this is possible thanks to the deformation of the material which constitutes the guide 43 and only in this case there is sliding without wear between the guide 43 and the shoulder 36.

 The shoulder 36 is pressed against the fixed guide 43A by the disc 42. The disc 42 does not hinder the rotation of the shoulder 36 since, free in rotation, it is driven without sliding by the shoulder 36.

 It should be noted that due to the difference in diameters between the pitch circle of the toothed pinion 28 and the shoulder 36, the toothed wheel 40 and the disc 42 rotate at different rotational speeds which does not constitute any drawback and is possible. since the return disc 42 is independent in rotation of the axis 41 or the end gear 40, but must be concentric.

 It should be noted that this dragging movement of the shuttles, at the level of the reference 9 (as at the level of the reference 8) is in no way hampered by a possible offset between the chain 16 of part 1 and that of part 2 , since the phase shift between the pinions 28 on either side of the shuttle has no importance for the drive of the shuttle; only the peripheral speed of the shoulders 36 matters, that is to say the rolling speed of the shoulders 36 on the fixed guide path 43 (43A).

 At the outlet of the return part 9, to the right of the axis YY, the return disc 42 no longer presses the shoulder 36 and the roller 30 is taken up by the guide path 13.

 It is the same at the level of the entry in the reference 9 but in this case the guide path of the lower profile is aligned with the rectilinear segment 43B of the fixed guide path 43 geometrically parallel to the disc 42.

 FIG. 4 also shows the casing 45 which surrounds and protects the reference 9.

 To simplify the description of the end gear it was chosen the free gear 9 (not motorized). But the motorized gear 8 has the same structure, the description of which will not be repeated, the only difference being the geared motor 10 connected to the axis carrying the toothed wheels which are then driven.

 A tensioner 12 will be described below with the aid of FIG. 5. The tensioner 12 is composed of a pinion without entry teeth 50 and a pinion without exit teeth 51 forming between them a loop passing over a pinion without return gear 52. The axis of the return pinion 52 is pushed by a spring member 53, for example an air spring 53. In fact1 the axis 54 of the return pinion 52 is supported by two spring members 53, twinned to maintain the parallelism of the displacement.

 The sprockets without teeth make the tension very quiet and avoid the clicking of a meshing, chain-sprocket, very important in small diameters.

 The chain 16 thus passes over the input pinion 50 then the return pinion 52 and the output pinion 51.

 The length of the loop formed by the chain 16 is variable over time; this length increases as a function of the elongation of the chain 16.

 The tensioner 12 is advantageously mounted on the casing 56 fixed for example to the lower 14 and upper 13 profile directly at the outlet of the drive gear 55 of the reference 8. It is however to be noted that the tensioner 12 could be placed at any location of the chain trajectory 16.

 However, the position described is the most favorable for ensuring proper operation; it makes this store universal, its kinematics does not change whether it is used in a store said "on the ground" or said "aerial".

 FIG. 6 shows a shuttle 5 carrying a plate 15 in line with a retractable stop according to the invention.

 This retractable stop is placed at a determined stop location for the shuttle 5. This stop corresponds for example to the loading or unloading of the tray 15 or more generally of the shuttle 5.

 The retractable stop consists of two roller-shaped retaining members 60, 61 carried by a plate 62 connected to piston rods 63, 64 of a double-acting pneumatic cylinder 65.

 The rollers 60 and 61 are made of a smooth coating coated with a plastic material "anti-rebound" meeting two functions: freedom in rotation of the rollers and absorption of the impact of the shuttles on them during a stop (reduction of shocks, vibrations ...).

 The jack controls the rollers 60, 61 in two positions. The first position is shown in solid lines in Figures 6 and 8; the second position is shown in dotted lines.

 The rollers 60, 61 are offset from each other in the transverse direction (perpendicular to the axis XX); they are movable integrally between the two positions to come alternately in the path shown by the axis XX.

 In the first position, the roller 60 is in the movement path XX of the shuttle 5 and stops the shuttle 5 which has a cleat 66 abutting the roller 60. When the roller 60 occupies its second position 60 ', the cleat 66 is released ; the shuttle 5 can then advance but it will meet the roller 61 occupying its position 61 '. The retractable stop 12 constitutes a sort of airlock which must be maneuvered and which allows the passage of only one shuttle at a time. This stop constitutes a safety means. The above description has assumed that the axis XX along which the cleat 66 of each shuttle circulates is the median axis. It is however possible to shift the assembly to one side or the other, that is to say the rollers 60, 61 and the tabs 66 of the shuttles.

 The plate 62 can be provided not with two rollers but with four rollers, or even more and providing a stop with multiple stop positions to allow the automatic loading or unloading of a shuttle receiving several parts or several tools.

 The stop is completed by a non-return stop 67 which retracts when passing the foundry bosses 68 and is raised behind them to take the position shown in solid lines in FIG. 6 (the retracting position is shown in broken lines).

 This cleat 67 prohibits movement of the shuttles 5 in the opposite direction.

 FIG. 8 shows the coupling 70 between two shuttles 5, 5 to form a train of shuttles receiving large parts or tools.

 The storage magazine described above is produced in modular construction for the rails, the feet, the deflection elements, etc. with a view to adapting to a very wide variety of requests.

 The store can be a ground transporter but also an air transporter without requiring any structural modification, the lower strand then constituting the outward strand and the upper strand the return strand. The driving end 8 can be kept for the same direction of circulation and the tensioner can remain in value of this driving end.

 In the case of an air carrier or store, the absence of intervention necessary to tighten the chains is an even more appreciable advantage than for a ground carrier.

Claims (1)

 10) Storage magazine for supplying work stations, magazine comprising - two endless, parallel drive chains,  traveling in synchronism passing over references  end wheel drive and den wheels  free tees, - guide and support rails, - a set of toothed pinion shuttles  ment and load-bearing rollers, the toothed gears generate  with chains to drive shuttles,  their rollers rolling on the guide rails and  support, - retractable stops defining the positions  shuttle stop, characterized in that A) Each shuttle (5) has a rolling member  (36) rotated by the toothed pinion (28)  associated, of the shuttle (5), B) The end gear (8, 9) of each chain (16),  (16B) includes  - a toothed wheel (40) over which the chain passes  (16), (16B),  - on the path of the running gear (36)  shuttles (5), a return disc (42),  coaxial with the idler gear (42) and free  in rotation, a return guide (43, 43B) in for  me of a circular arc partially surrounding the  deflection disc (42) for defining therewith  a radial width drive path (B)  slightly smaller than the diameter (D) of the organs  bearing (36) thereby forming a path for  these rolling bodies, C) Toothed pine nuts (28) on each side of the turnip  te (5) are independent, D) A loop tensioner (12) is provided independently  for each chain (16), (16B) to apply it  a determined tension and compensate for its extension  is lying.  2 ') Store according to claim 1, characterized in that the rolling members (36) are shoulders carried by the pins (34) of the shuttles.  3 ') Store according to claim 1, characterized in that the tensioner (12) comprises an input sprocket (50), an output sprocket (51) and a sprocket (52) closing the loop for the chain (16) , the latter pinion (52) being mounted on a spring assembly (53) ensuring the tension of the chain.  4 ') Store according to claim 1, characterized in that it comprises at least one retractable stop formed by two rollers (60, 61) offset relative to the axis of travel of a cleat (66) integral with each shuttle (5), these rollers (60, 61) being mounted on a plate (62) controlled between two positions, one by which one of the rollers (60, 61) blocks the cleat (66) coming into the path of the cleat (66) and the other by which the preceding roller (60) releases the cleat (66) and the following roller (61) comes in the path XX of the cleat (66) to stop it.