WO2006128987A1

WO2006128987A1 - Pilgrim step conveyor adapted to support thermal variations

Info

Publication number: WO2006128987A1
Application number: PCT/FR2006/001096
Authority: WO
Inventors: Claude Canolle; Alain Lanteri
Original assignee: Vit
Priority date: 2005-05-30
Filing date: 2006-05-16
Publication date: 2006-12-07
Also published as: FR2886280B1; FR2886280A1

Abstract

The invention concerns a pilgrim step conveyor comprising a chassis bearing fixed rails (7) and mobile rails (10), the mobile rails (10) are mounted on cross-members (9) linked to laterally sliding side-members (11) to slide on profiled lifting sections (12) so as to enable the mobile support rails to be displaced in separate lifting motion and sliding motion, and the profiled lifting sections are linked to thermally deformable chassis elements (16) having a reference portion rigidly linked to a portion of the chassis forming a frame and mounted freely outside the reference portion.

Description

Pilgrim step conveyor adapted to withstand thermal variations.

The present invention relates to a pilgrim conveyor, particularly although not exclusively for the heat treatment of electronic boards in a reflow oven. BACKGROUND OF THE INVENTION

Document US Pat. No. 5,334,014 discloses a pilgrim-like conveyor comprising a frame carrying fixed support rails and movable support rails associated with lifting members and sliding members in order to move the movable support rails in a movement movement. separate lifting and sliding movement.

In this document, the pilgrim conveyor is intended to be used in a high temperature treatment furnace (1600 ^° C.) and the main concern is to protect the various components of the conveyor from heat. For this purpose the movements of the movable support rails are obtained by connecting them to a central mast which extends into a well made of insulating material and is connected to the lifting and sliding members below the well.

Given the structure of this conveyor, it is not possible to provide accurate guidance of the items being transported and it is therefore not possible to envisage its use in a reflow oven where the electronic boards must be displaced with very great precision between compartments whose temperature varies very significantly, typically from 80 ^° C. to 300 ^° C. OBJECT OF THE INVENTION

An object of the invention is to provide a pilgrim step conveyor ensuring precise movement of articles despite temperature variations in the space surrounding the conveyor. SUMMARY OF THE INVENTION

In order to achieve this goal, according to the invention, a pilger-like conveyor comprising a frame carrying fixed support rails and movable support rails associated with lifting members and sliding members is provided to perform a moving the movable support rails according to a separate lifting movement and a sliding movement, in which the movable support rails are mounted on sleepers connected to lateral sliding side members associated with the sliding members for sliding on lifting profiles connected to the members in which the lifting profiles are connected to thermally deformable frame members having a reference part rigidly connected to a frame part and mounted free outside the reference part.

According to an advantageous version of the invention, the sliding members comprise chains each having ends attached to a sliding spar and associated with a drive pinion; preferably the chains pass over return pulleys to form a loop around the drive pinion.

According to another advantageous aspect of the invention, the lifting members each comprise an eccentric disc arranged in a frame connected to a lifting profile.

According to another advantageous aspect of the invention, the support rails comprise thin support strips attached to the support rails for projecting from an upper edge of the support rails.

BRIEF DESCRIPTION OF THE DRAWINGS

Other characteristics and advantages of the invention will appear on reading the description which follows of a particular non-limiting embodiment of the pilger-like conveyor according to the invention, in relation to the attached figures among which:

FIG. 1 is a partial perspective view illustrating the structure of the chassis of the conveyor according to the invention,

FIG. 2 is a schematic perspective view illustrating a basic structure of the conveyor according to the invention, FIG. 3 is a partial perspective view showing the arrangement of a lifting member and the relationship with a sliding spar. to which is connected an end of a sliding member,

FIG. 4 is a perspective view of the movement control of the lifting members,

FIG. 5 is a partial perspective view illustrating the structure of the sliding members,

FIG. 6 is an elevational view of the end of a fixed support rail and a movable support rail assembled and of the housing supporting them.

DETAILED DESCRIPTION OF THE INVENTION With reference to FIG. 1, the conveyor frame according to the invention comprises a vertical front base plate 101 which extends on one side of the conveyor. The ends of the front base plate 101 are connected by spacer plates 102, only one of which is shown in FIG. 1, to an upper side plate 103 which extends horizontally above the opposite side of the conveyor plate. front base 101. The front base plate 101, the spacer plates 102 and the upper side plate 103 thus constitute a frame portion forming a frame generally designated by the numeral 104. At mid-distance between the spacer plates 102, a reference bracket 105 is rigidly fixed to the front base plate 101 via a thermally insulating block 106. An elongate thermally deformable support plate 16, for example a plate aluminum, is disposed horizontally in a longitudinal direction of the conveyor and comprises a central reference portion which is rigidly fixed to the bracket 105. The support plate 16 extends on either side of the central reference part and supports in the vicinity end of the brackets 107 (only one of which is shown in Figure 1) attached to the plate 16 and having at their upper part a horizontal wing bearing on a thermally insulating block 108 attached to the front base plate 101. The stem 107 is thus free to slide during longitudinal deformations of the support plate 16 under the effect of temperature variations. In this way, transverse deformation of the support plate 16 in the different temperature zones traversed by the support plate 16 is avoided, and the deformation that would be caused by the difference in expansion between the support plate 16 and the base plate 101 is avoided. .

On the opposite side of the conveyor, the frame comprises a central mat 109 which extends vertically under the upper base plate 103 and is rigidly secured thereto by means of a thermally insulating block 110. 111 similar to the stem 105 is rigidly fixed to the central mat 109 to extend in front of the bracket 105. A second support plate 16 similar to the support plate 16 described above, extends longitudinally on the side of the conveyor and has a central reference part which is rigidly fixed to the bracket 111. In the vicinity of the ends of this support plate and facing the brackets 107, the chassis of the conveyor comprises brackets 112 attached to the support plate 16 and having in the vicinity of their upper part, a horizontal wing which bears on a block 113 carried by a mat 114 attached to the upper base plate 103 via a thermally insulating block 115. As for the support plate 16 associated with the bracket 105, the support plate 16 associated with the bracket 111 is thus fixed in its central part of the frame. and is free to deform longitudinally outside the reference part. The support plate 16 therefore undergoes no transverse deformation as it passes through the conveyor zones at different temperatures and regardless of the temperature difference between the support plate 16 and the upper plate 103.

With reference to FIG. 2, this illustrates a basic structure of the conveyor according to the invention in an extremely schematic manner and for a better understanding these different elements have been represented in dimensions and distances unrelated to reality.

According to this very schematic illustration, the brackets 107 and 112 are connected in pairs by transverse beams 2 on which are mounted a pair of housings 3 which are fixed in a specific position on the transverse beams 2 and a pair of mobile housings 4 which are The position of each mobile housing 4 is adjusted by a worm 5 having an end attached to a mat 114 to rotate freely therewith and cooperating with a housing nut. corresponding 4 and driven in rotation by a motor 6 carried by the front base plate 101 (Figure 1). The fixed housings 3 are simply crossed by the screws without end 5 without interaction between the worm and the housings 3. In order not to interfere with the worm 5 during the length variations of the support plates 16, the brackets 107 and 112 comprise oblong slots for the passage of the screws 5.

Each pair of housings carries a fixed rail 7 which is fixed to the upper part of the corresponding housings. Each fixed rail 7 has windows 8 to allow a passage and a movement movement of sleepers 9 carrying movable rails 10. The ends of the crosspieces 9 are fixed to side rails 11. The movable rails 10 associated with the mobile housings 4 are mounted on the sleepers 9 with sufficient clearance to allow frictionless lateral displacement of the movable rails 10 during the lateral displacement of the housings 4. The movable support rails 10 are preferably mounted outside the fixed rails 7 with respect to a longitudinal axis of the conveyor.

The side rails 11 are mounted by means of anti-friction rods 13 for sliding on lifting profiles 12. The side rails 11 are moved by sliding members not shown in FIG. 2 and simply symbolized by arrows double horizontal on this figure. The lifting profiles 12 are carried by lifting plates 14 associated with the chassis of the conveyor by lifting members not shown in Figure 2 and simply symbolized by double vertical arrows in this figure.

Figure 3 partially illustrates an embodiment of the invention. In this figure the elements already described are illustrated with the same reference numeral, additional numerals are assigned to the elements not shown in Figure 2. In particular, this figure illustrates, in relation to a bracket 112, a lifting member comprising an eccentric disk 15 carried by the support plate 16. An eccentric cage 17 is supported by the eccentric disk 15 and is fixed to its lower part to the corresponding lifting plate 14. The conveyor has two lifting members on each side and the eccentric discs 15 are controlled simultaneously as illustrated in FIG. 3 by a linkage 18 associated with an axis 19 connected to a motor 39 carried by the front base plate 101 (FIG. 1).

As illustrated in FIG. 3, the movement in a vertical direction only of the lifting plates 14 is obtained by means of guide plates 20 carried by the support plates 16 and comprising a vertical light 21 in which is engaged an ergot 22 worn. by the corresponding lifting plate 14.

As illustrated in FIG. 5, the sliding members according to the invention are carried by the potentials 105 and 111. In the example illustrated, the bracket 111 supports a splined shaft 24 rotated by a motor 25 carried by the front plate 101. The axis 24 carries a pinion 26 on which a chain 27 forms a loop holding the chain 27 applied to the pinion 26. On either side of the pinion 26 the chain 27 extends substantially vertically and The ends of the chain 27 are fixed at two points spaced apart from a lateral sliding lenght 11 by means of flanges 29.

Preferably, as illustrated in FIG. 5, the drive shaft 24 passes through the conveyor and serves to drive a pinion 26 of an identical sliding member carried by the bracket 105 on the opposite side of the conveyor. voyeur. The two sliding members are thus driven in synchronism. The two sliding members are preferably mounted at mid-distance from the ends of the conveyor. As is illustrated by double thick arrows in FIG. 5, the lifting movements of the sliding rails are possible without blocking of the sliding members due to a pivoting of the end strands of the chain 27 around the pulleys. reference 28.

To allow a lateral movement in both directions of the movable rail 10 associated with a mobile housing 4, the fixed rail 7, fixed to the housings 4, is preferably associated with a cheek 30 (see FIG. 5) connected to the fixed rail 7 by means of spacers 31 so as to take the movable rail 10 sandwich without hindering the movements thereof.

With reference to FIGS. 3 and 6, the conveyor according to the invention in its preferred embodiment comprises provisions that minimize heat transfer by longitudinal conduction of the rails and by contact between the support rails and the boards conveyed by the conveyor. For this purpose, the fixed rails are preferably equipped with thin support strips 32 fixed to the fixed support rails to extend projecting from an upper edge of the rails. Similarly, the movable rails 10 comprise thin support blades 33 fixed to the movable support rails 10 to extend projecting from an upper edge of the rails. The support blades 33 preferably comprise a guide ramp 37 and are equipped with a lifting bar 38 projecting from the side of the guide ramp 37. Preferably to further minimize transfer by conduction, the support blades 32, 33 comprise notches 34 that extend between the points of fixing 35 of the support blades on the support rails.

In addition, in order to minimize longitudinal thermal conduction in the support strips, these are preferably divided into segments separated by an interval 36 (Fig. 3) corresponding to the boundary between two chambers at different temperatures.

In a stop position, the electronic boards bear on the upper edge of the thin support blades 32. From this position the eccentric 15 are operated to lift the lifting profiles 12 which cause the sleepers 9 upwardly. and consequently bring the lifting bars 38 into contact with the underside of the card, the guide ramp 37 of the blade 33 simultaneously ensuring correct lateral positioning of the card. For a high position of the lifting members, the electronic card is thus maintained above the upper edge of the support blades 32 and a maneuvering of the sliding members causes a longitudinal displacement of the electronic card without friction. After stopping the slide, the lifting members are maneuvered down to rest the electronic board on the upper edge of the thin blades 32, and the sliding members are maneuvering to return the movable support rails to their starting position.

Of course, the invention is not limited to the embodiment described and variants may be provided without departing from the scope of the invention as defined by the claims. In particular, although the invention has been illustrated with only two pairs of support rails, a third pair of rails may be provided mid-way between the pairs of side rails to avoid buckling of the electronic boards conveyed by the conveyor. The number of pairs of support rails can also be increased so that several lines of cards can be simultaneously run in parallel.

Similarly, the conveyor according to the invention can be made with different lifting members and different sliding members mounted on the sides of the frame for lifting the sliding rails while allowing variations in expansion of these side members without harming their sliding and without harming the parallelism of the rails card holders.

Although the support rails have been illustrated in the form of plates, they can be made in the form of tubular elements.

Although the thin support strips have been illustrated with indentations on the side of the support rail, the notches can be made on the free edge side or simultaneously on both sides of the support strips.

Although the invention has been illustrated with thermally deformable frame members in the form of support plates 16 attached to the brackets 105 and 111 in a central area of the support plates, these elements may have any suitable shape and be attached to the reference frame by any reference part, for example one end, the rest of the support plate remaining free to elongate to prevent deformation that would result from differential expansion between the support plates 16 and colder parts of the frame and which could lead to a diversion of items carried during successive transfers.

Claims

A pilger-like conveyor comprising a frame carrying fixed support rails (7) and movable support rails (10) associated with lifting members and sliding members for moving the movable support rails (10) in a manner Separate lifting and sliding movement, characterized in that the movable support rails (10) are mounted on sleepers (9) connected to lateral sliding rails (11) for sliding on connected lifting profiles (12). to the lifting members, and in that the lifting profiles are connected to thermally deformable frame members (16) having a reference part rigidly connected to a frame part and mounted free outside the frame part. reference .

2. Conveyor according to claim 1, characterized in that the reference part is a central part of the thermally deformable frame elements.

3. Conveyor according to claim 1, characterized in that the frame portion forming a frame is connected to the heat-deformable frame members through thermally insulating blocks.

4. Conveyor according to claim 1, characterized in that the sliding members comprise chains (27) each having ends attached to a sliding beam (11) and associated with a drive pinion (26).

5. Conveyor according to claim 4, characterized in that the chains (27) pass over return pulleys (28) to form a loop around the drive pinion (26).

6. Conveyor according to claim 1, characterized in that the lifting members each comprise an eccentric disc (15) arranged in a frame (17) connected to a lifting profile (12).

7. Conveyor according to claim 1, characterized in that the fixed rails (7) and the movable rails

(10) are associated in pairs, at least one pair being mounted on mobile housings (4) to ensure a lateral displacement of the corresponding support rails.

8. Conveyor according to claim 1, characterized in that the support rails (7, 10) comprise thin support strips (32, 33) attached to the support rails for projecting from an upper edge of the support rails. .

9. Conveyor according to claim 8, characterized in that the thin support strips (32, 33) comprise indentations (34).

10. Conveyor according to claim 9, characterized in that the notches (34) extend between fixing points (35) of the support blades on the support rails.

11. Conveyor according to claim 8, characterized in that the support blades (32,33) are divided into segments separated by intervals (36).