Friction device for the drive of continuous conveyor carriages

Abstract: Friction device for the drive of continuous conveyor carriages, of those required in rail motor carriages of a suspended type, used in continuous transport of parts and which include at least one hinged arm with an auxiliary wheel (4) which is in contact with the drive wheel (2) of the rail motor carriage when an auxiliary guide rail (3a) operates on it, which is placed parallel to the main guide rail (3) in slopes of the run, characterised in that the auxiliary wheels are mounted on the front ends of arms of variable length and have elastic devices which tend to keep them in an extended position, and a characterised spin axis, to be mounted on the chassis of the rail motor carriage; allowing the whole device to be removed by releasing this axis.

Description: PURPOSE OF THE INVENTION The invention refers to a friction device needed in rail motor unit carriages to maintain the drive effect when slopes would cause the drive wheel to slip on the guide rail. BACKGROUND OF THE INVENTION Rail motor unit carriages used in interior conveyor systems have difficulties in going up slopes in the guide rail. This problem is currently solved by placing an auxiliary guide rail parallel, above the main guide rail, and furnishing the rail motor unit carriage with at least one auxiliary wheel assembled on swivel arms, so that it is positioned sideways above the drive wheel. The auxiliary guide rail causes the auxiliary wheel to descend and press on the drive wheel, so that the friction between this wheel and the main guide rail increases and the drive wheel does not slip on the main guide rail -which would eliminate the movement of the carriage- but continues its drive operation. As background to the invention, it is important to mention Utility Model 9500436 and German Patent DE 3905210. In the above mentioned Utility Model, the auxiliary wheel is mounted on the central part of a swivel arm with one end mounted on a axis fixed to the carriage chassis. This arm tends to fold on the drive wheel by means of a spring which operates on the opposite end of the aforementioned lever. In patent DE-3905210, the auxiliary wheel is mounted on a set of articulated levers which are held in the axis itself of the drive wheel and maintains contact between the auxiliary wheel and the drive wheel by means of a spring operating on the free end of the set of levers. In current friction devices, the drive and auxiliary wheels are mechanically and interdepedently linked, and therefore the problem arises in that to change the auxiliary wheel, a considerable number of common parts have to be dismounted, which means excessive repair time for industry, bearing in mind that the blockage of one of the carriages could mean that parts are not being supplied to a production line. DESCRIPTION OF THE INVENTION To solve the aforementioned problem, it is planned for the auxiliary wheel or wheels to be mounted completely independent from the drive wheel. They are assembled on one of the ends of the hinged arm connected to the rail motor carriage by means of a transversal axis. To achieve the necessary pressure of the auxiliary wheel or wheels on the drive wheel on slopes, it is planned for the support arm to have elastic devices in its intermediary part which tend to move the wheel lengthways with respect to the arm, keeping it away from the arm's spin axis. These elastic devices also mean that the auxiliary wheel can move lengthways towards the rear area of the arm when the auxiliary guide operates on it, thereby maintaining the required pressure on the drive wheel. The main advantage of the invention is that the arm and the auxiliary wheel form a unit which can be separated from the carriage quickly and simply without the need to dismount the drive wheel nor any other component of the carriage, therefore saving a considerable amount of time. DESCRIPTION OF THE DIAGRAMS Figure 1 shows a profile view of the device applied to a rail motor carriage. Figure 2 shows a plan view of the same device, with the assembly of the arm on the carriage chassis. Figure 3 shows a partial view of the carriage, in which one of the sides of the chassis have been removed, and showing a cross section of the rear area of the arm. Figure 4 shows a side view outline of the same carriage, this case with two swivel arms with the corresponding auxiliary wheels. PREFERENTIAL MANUFACTURE OF THE INVENTION In the figures shown, the carriage consists of a chassis (1) furnished with a drive wheel (2) which stands on the main rail (3) to cause the latter to go forward. One or two auxiliary wheels (4) stand on the drive wheel (2), mounted on the corresponding swivel arm. The purpose of these auxiliary wheels is to press on the drive wheel when they move towards the lower area by means of an auxiliary rail (3a) parallel to the main rail (3) and located on slopes of the run. The swivel arm consists of two cylindrical parts (5 and 6) mounted telescopically and which tend to stay in the extended position by the action of a helicoidal spring (7). The rear part (5) has two side nipples (5a) which form the spin axis of the arm and which are assembled on supports (8) which are inserted in the chassis (1) through the open round-ended holes (1a); fixing the supports (8) to the chassis by means of bolts (8a). This assembly of the arm means that it can be released from the chassis by simply removing the bolts (8a). The front part (6) of the arm has a fork (6a) on which the axis (4a) of the auxiliary wheel (4) is assembled, and above, a non-rotation guide rail (6b) provided with a round-ended hole (6c) in which a bolt (5b) is loosely placed and fixed to the rear part (5) of the arm.

Claims: Friction device for the drive of continuous conveyor carriages, of those required in rail motor carriages of a suspended type, used in continuous transport of parts and which include at least one hinged arm with an auxiliary wheel (4) which is in contact with the drive wheel (2) of the rail motor carriage when an auxiliary guide rail (3a) operates on it, which is placed parallel to the main guide rail (3) in slopes of the run, characterised in that the auxiliary wheels are mounted on the front ends of arms of variable length provided with elastic devices which tend to keep said arms in an extended position, and in that said arms are rotatably and releasably mounted on the chassis of the rail motor carriage by means of a spin axis; allowing the whole device to be removed by releasing this axis. Device, according to the previous claim, characterised in that the arm is composed of two parts (5 and 6) assembled telescopically. Device, according to the previous claims, characterised in that the elastic devices included in the arm are composed of a helicoidal spring (7) placed lengthways between parts (5 and 6) forming the arm. Device, according to the previous claims, characterised in that the spin axis of the arm is composed of two aligned nipples (5a) which go sideways from the rear part (5). Device, according to the previous claims, characterised in that the nipples forming the axis are mounted on support parts (8) which are inserted into open round-ended holes (1a) defined in the chassis (1) fixed by bolts (8a). Device, according to the previous claims, characterised in that the front part (6) of the arm has a front fork (6a) in which the axis (4a) of the auxiliary wheel (4) is mounted. Friction device, according to the previous claims, characterised in that the front part (6) of the arm has an upper non-rotation guide rail (6b) provided with a round-ended hole (6c) in which a bolt (5b) is loosely placed and fixed to the rear part (5) of the arm.

Inventors: LOPEZ ALBA ADELARDO, LOPEZ ALBA, ADELARDO
Applicants: TRANSPORTES CONTINUOS INTERIOR, TRANSPORTES CONTINUOS INTERIORES S.A.
Application year: 1997
Main classification: B61C13
IPC codes: B61C13