GB2093387A

GB2093387A - Welding machine for making brake shoes

Info

Publication number: GB2093387A
Application number: GB8204513A
Authority: GB
Original assignee: Fulminawerk KG Franz Muller Gm
Current assignee: Fulminawerk KG Franz Muller Gm
Priority date: 1981-02-18
Filing date: 1982-02-16
Publication date: 1982-09-02
Also published as: FR2499890A1; DE3105968A1; IT1157629B; IT8212437A0; JPS57152379A

Abstract

A welding machine for welding together the lining plate (7) and the web plate (8) of brake shoes comprises a welding wheel (1) which receives the brake-shoe parts and which holds them in a state braced relative to one another. To guarantee especially accurate and uniform running of the welding wheel (1) and to achieve welding beads between the lining and web plates which are placed correspondingly precisely by electrodes (9), the welding wheel (1) is guided both radially and axially via a single ball-bearing (11), the diameter of which corresponds approximately to that of the welding wheel. <IMAGE>

Description

SPECIFICATION Welding machine for making brake shoes The invention relates to a welding machine for welding together the lining plate and the web plate of brake shoes, with a welding wheel which receives the brake-shoe parts and which holds them in a state braced relative to one another, and with an electrode feed device which is assigned to this welding wheel and by means of which, during a rotary movement of the welding wheel, a welding bead is placed at each point of contact between the lining plate and web plate, and the length of the welding bead can be determined via cams controlling the welding operation and adjustable on the welding wheel.

In known welding machines of this type, the welding wheel is guided radially between three rollers distributed uniformly on the periphery.

Collars which project in the centre of each of the rollers and which engage into a guide groove extending around the periphery of the welding wheel serve for the axial guidance. It has been shown that the welding beads placed by means of a welding wheel mounted and guided in this way leave much to be desired in terms of uniformity and accuracy.

The object on which the invention is based is to design the welding machine of the type mentioned in the introduction so that especially accurate and uniform running of the welding wheel is guaranteed.

According to the invention there is provided a welding machine for brake shoes comprising a wheel mounted for rotation on a ball-bearing having a diameter substantially equal to the diameter of the wheel, means mounted inside the rim of the wheel for receiving and bracing together prior to welding a web plate and a lining plate for a brake shoe, means for partially rotating the wheel perpendicular to its axis and means for welding together the braced lining and web plates during such rotation.

Suitable one race, preferably the outer one, of the ball-bearing is a gear wheel, engaged by another gear wheel which transmits drive to the welding wheel from a hydraulic motor or the like.

Particularly accurate adjustment of welding can be achieved by using adjustable interacting sets of switches and contacts to control rotation of the wheel, one set being fixedly mounted and the other set being mounted on the outer rim of the wheel to rotate therewith.

This object is achieved, according to the invention, essentially due to the fact that the welding wheel is guided both radially and axially via a single ball-bearing, the diameter of which corresponds approximately to that of the welding wheel. Undesirable jolting movements or vibrations of the welding wheel are avoided when a guide in the form of a large ball-bearing of this type is used. The position and course of the welding bead are thus not impaired.

It has proved especially appropriate, specifically both in terms of construction and in terms of achieving a very quiet and accurate rotation of the welding wheel, if the inner race of the ball-bearing is made stationary and the outer race connected to the welding wheel is designed as a gear wheel connected to the drive in the form of a hydraulic motor/worm gear unit. In this case, the outer race of the ball-bearing can serve as a shoulder rest for the welding wheel and thus guarantee its accurate rotation in a plane perpendicular to the axis of the welding wheel. Moreover, this drive ensures, via the gear wheel, a precise control of the start of the rotary movement at points of time exactly predetermined uniformly over the entire path up to stopping, since the advantages of a hydraulic motor, which emerge here above all, can be utilised to an especial degree via the gear wheel.

In the conventional welding machine mentioned in the introduction, V-belts are inserted in fact between the welding wheel and the drive motor, and only uneven starting is possible via these because of the size of the mass of the body to be moved. The known slip effect in belt drives also contributes to inaccurate slowing-down. Desirably uniform welding beads which extend over a precisely predetermined region cannot be obtained by means of this known drive. However, they can be obtained immediately by relatively simple means, namely by the use of the ballbearing mounting for the welding wheel and its drive via the' outer ball-bearing race, designed as a grear wheel, of a hydraulic motor with a worm gear, since, in just the same way as exact starting, the predetermined stopping is also possible, without any detectable over-running.

In a further embodiment of the welding machine according to the invention, it has provided especially advantageous in terms of an exact movement control if, for an accurate control of the rotary movement of the welding wheel, there is on the approximately cylindrical shell of the welding wheel, a plurality of cam tracks which are arranged parallel next to one another and on which cams controlling various functions, such as advance, return, interruption, tension, release, etc., and interacting with stationary switches, can be adjusted. As a result of this arrangement of the cam tracks, they acquire the best possible diameter and permit especially fine adjustment.

Furthermore, the region of the welding wheel on its end face, hitherto provided for this purpose, is kept free. The inner region of the welding wheel, in which the clamping holders for the brake shoes are located, becomes more easily accessible.

Further details, advantages and features of the invention emerge from the following description and the drawing to which express reference is made regarding disclosure of all details not described in the text.

Fig. 1 shows a front view of the welding machine with the welding wheel designed and mounted according to the invention, Fig. 2 shows a side view, partially in section, of the machine according to Fig. 1, and Fig. 3 shows a plan view of the machine according to Fig. 1.

As is evident from the drawing, the welding machine illustrated comprises a welding wheel 1 which is composed of shaped pieces 2 and 3 connected to one another by welding and of webs 4 which make a connection to a cam ring 5.

Within the welding wheel 1 , the lining plate 7 and the web plate 8 of the brake shoes are brought, by means of a receiving device 6 not illustrated in any more detail, into a state braced relative to one another and are held in this state, until, during a rotary movement of the welding wheel, a welding bead is placed at each point of contact between the lining plate 7 and web 8 by means of electrode feed devices 9 assigned to the welding wheel 1.

To permit a precise rotary movement of the welding wheel 1, it is guided both radially and axially in the machine frame 10 of the welding machine via a single ball-bearing 11, the diameter of which corresponds approximately to that of the welding wheel 1.

Figs. 2 and 3 show clearly that the inner race 12 of the ball-bearing 1 1 is made stationary on the machine frame 1 0. The outer race 13 of the ball-bearing 1 which is connected firmly to the welding wheel 1, is designed as a gear wheel.

Engaged with this gear wheel is a driven gear wheel 14 which rests on the driven shaft 15 of a hydraulic motor/worm gear unit 16 fixed on the machine frame 10. The electrode feed device 9 comprises, in a known manner, supporting arms 18 connected to an adjusting device 17.

For the accurate control of the rotary movement of the welding wheel 1, there is on the shell of the cylindrical cam ring 5 of the welding wheel 1, a plurality of cam tracks 19 which are arranged parallel next to one another and which are indicated diagrammatically in Fig. 3 only.

Cams 20 which interact with stationary switches 21 can be adjusted respectively on these tracks.

These cams 20 control, together with the switches 21, various functions of the machine, such as advance, return, interruption, tension, release, etc., specifically with high accuracy, due to the fact that they are located on the outer side of the welding wheel and thus have the best possible diameter, so that an especially fine adjustment is possible.

Claims

1. Welding machine for brake shoes comprising a wheel mounted for rotation on a ball-bearing having a diameter substantially equal to the diameter of the wheel, means mounted inside the rim of the wheel for receiving and bracing together prior to welding a web plate and a lining plate for a brake shoe, means for partially rotating the wheel perpendicular to its axis and means for welding together the braced lining and web plates during such rotation.

2. Wending machine according to claim 1 wherein one race of the ball-bearing is stationary and the other is connected to the welding wheel and formed as a gear wheel which engages with another gear wheel transmitting drive to the welding wheel.

3. Welding machine according to claim 2 in which the outer race is connected to the welding wheel and formed as a gear wheel.

4. Welding machine according to claim 2 or claim 3 wherein the drive is by a hydraulic motor.

5. Welding machine according to one of claims 1 to 4 wherein rotation of the wheel is preset by adjustable interacting sets of switches and contacts, one set fixedly mounted and the other set mounted in outer rim of the wheel to rotate therewith.

6. Welding machine for welding together the lining plate and the web plate of brake shoes, with a welding wheel which receives the brake-shoe parts and which holds them in a state braced relative to one another, and with an electrode feed device which is assigned to this welding wheel and by means of which, during a rotary movement of the welding wheel, a welding bead is placed at each point of contact between the lining plate and the web plate, and the length of this welding bead can be determined via cams controlling the welding operation and adjustable on the welding wheel, characterised in that the welding wheel is guided both radially and axially via a single ball bearing the diameter of which corresponds approximately to that of the welding wheel.

7. Welding machine according to claim 6, characterised in that the inner race of the ballbearing is made stationary and the outer race connected to the welding wheel is designed as a gear wheel connected to the drive in the form of a hydraulic motor-worm gear unit.

8. Welding machine according to claims 6 or 7, characterised in that, for the accurate control of the rotary movement of the welding wheel, there is on the approximately cylindrical shell of the welding wheel, a plurality of cam tracks which are arranged parallel next to one another and on which cams controlling various functions, such as advance, return, interruption, tension, release, etc., and interacting with stationary switches, can be adjusted.

9. Welding machine substantially as hereinbefore described with reference to the accompanying drawings.