The present invention relates to a method and an apparatus for turning one-sided open, edge joined and semistiff, small objects such as leather and vinyl casings or gloves, particularly relatively stiff working gloves. Ordinary, semistiff working gloves, which should be turned after being edge stitched, are quite difficult to turn, and it is a rather hard manual job to turn such objects. Of course, various auxiliaries can be used, but generally the turning operations have the character of a manual work requiring a notable amount of work. The known auxiliaries are based on the use of one or more tubes for receiving the object or parts thereof, e.g. glove fingers, and the turning is effected by means of thin steel rods for pushing the parts to be turned into the tubes; however, this often gives rise to an over¬ stretching or rupturing of the turned parts.

In other areas of the confection industry it is well known to effect an automatic turning of purl stitched products, particularly sleeves and trouser legs, viz. with the use of turning devices based on a turning tube, through which a strong air flow is drawn to a suction blower from a turning nozzle on the tube; When the root end of the sewed tubular workpiece is placed reasonably tightly against this nozzle the work¬ piece will be sucked into the turning tube so as to have its free end located rearmost therein, whereafter the workpiece can just be pulled out of the tube, now in a turned condition. This technique is based on a strong air flow capable of flowing through tubular workpieces or through workpieces having air permeable walls, and thus it is not applicable for the turning of otherwise

closed, semistiff articles of the type here considered.

It has been attempted to use more powerful, mechan¬ ically operating turning devices for this purpose, bo no such devices have been provided, which could compete with the manual turning of the heavy workpieces.

It has been proposed earlier to turn even one-sided open workpieces with the use of a suction blower. Thus, in US-A-1,668,397 a turning apparatus for glove fingers is disclosed, and in US-A-4,180,190 a turning apparatus for larger workpieces, e.g. S BC6KKE, but the former apparatus will not be able to handle heavy or rather stiff workpieces, and for the latter apparatus it will correspondingly be limited how small the relevant semi¬ stiff workpieces can be.

In connection with the invention it has been rea¬ lized that it is nevertheless perfectly possible to make use of the said pneumatical turning method, viz. when using, in stead of a strong air flow or the suction from a suction blower, a real vacuum. An apparatus according to the invention, therefore, will not be based on a suction blower, but on a real vacuum pump, which will serve to maintain a strong vacuum in a vacuum container, from which a suction conduit to the turning nozzle ex¬ tends through an operator controlled valve, preferably a solenoid valve, which is shifted between a fully closed and a fully open condition.

For each turning operation it will only be required to suck in a relatively small air volume to the vacuum tank, but in order to maintain a very high vacuum with¬ out using an excessively large and expensive vacuum pump it is important to use a vacuum tank having a volume which is much larger than the volume of the workpieces to be turned. Then a reasonably small vacuum pump can operate more or less continually for maintaining a high vacuum in the tank while the latter is used for succes¬ sive turnings. When the tank is large the pressure in-

crease therein for each turning operation will be almost insensible, and it is important that a high vacuum be maintained during the entire turning operation.

An alternative possibility is to create the re¬ quired high vacuum in a more dynamical manner, viz. by a strong actuation of a piston in a suction cylinder for the accomplishment of each single turning operation. When care is taken to keep the unavoidable dead space between the advanced piston and the turning nozzle as small as possible, then a rapid retraction of the piston in a reasonably large cylinder can create a very high vacuum at the turning nozzle, and here the said dead space can be kept small because only the turning of relatively small workpieces will be relevant.

For the turning of a glove the glove fingers should first be individually turned, with the finger root held against a correspondingly adapted turning nozzle, where¬ after the main portion of the glove is turned; optional¬ ly this latter turning may be effected manually, as it is easier than the finger turning to accomplish. In both cases, however, it will be sufficient to operate with a relatively modest volume of air, such that with the said

* simple means it is possible to produce the required strong suction. Any false air intake should be avoided, while this is less important with the known pneumatic turning devices for air permeable materials, yet it is a lucky circumstance that by the holding against the turn¬ ing nozzle of the root portion of the part to be turned the tightness of this engagement will automatically be promoted by the very initial suction on the workpiece. In principle it will be possible to make use of the turning nozzle according to the said US-A-1,668,397, which is adapted to cooperate with all five glove fin¬ gers at the same time; with the invention, however, it is important to operate with a high degree of tightness, and it will be difficult to secure a full sealing by

arranging for a nozzle contact with all five fingers at one time.

Thus, an apparatus according to the invention for turning gloves of a substantially non-air-permeable material should be provided with mutually different vacuum nozzles for cooperation, respectively, with the single clove fingers, i.e. a relatively narrow nozzle, and with the hand root portion of the glove, i.e. a considerably broader nozzle, as well as with valve means for selective connection of the nozzles with the vacuum source.

Suitably the apparatus should also be provided with a vacuum regulator, as the apparatus will then be more universally applicable. For heavy workpieces it may be necessary to work with an almost absolute vacuum, but in that case the same apparatus would not be usable for turning workpieces of a supple and fully tight material, e.g. thin vinyl gloves, which would burst by the strong vacuum. A suitable adjustment range can be 50-98/99% vacuum.

In the following the invention is described in more detail with reference to the drawing, in which:-

Fig. 1 is a schematic view of an apparatus accord¬ ing to a first embodiment of the invention,

Fig. 2 is a schematic view of a double nozzle system, and

Fig. 3 is a schematic view of another embodiment of the apparatus.

In Fig. 1 the element designated 2 is a real vacuum pump, i.e. not a suction blower, and at its suction side this pump is connected through a filter 4 with a vacuum container 6, e.g. of 200 liters and designed for 100% vacuum. Through a pipe 8 this container is connected with an adaptor 10 for holding different, exchangeable nozzle tubes 12, and in the pipe 8 there is arranged a solenoid valve 14 operable from a foot pedal 16. The

container or tank 6 is also connected with a so-called snuffle valve 18, which will enable the vacuum in the tank 6 to be adjusted to a desired value; a correspond¬ ing adjustment unit may be arranged in integral con¬ nection with the vacuum pump 2 itself.

The nozzle tube 12 is selected so as to accommodate the opening of the workpiece 20 to be turned , and when the opening of the workpiece has been brought into a tight engagement with the mouth of the nozzle tube the foot pedal 16 is actuated for applying the vacuum onto the nozzle tube and thus also onto the workpiece to be turned. Thereby the latter will be drawn strongly into the nozzle tube, whereafter it can be retracted there¬ from upon the pedal 16 being released.

In this manner it is possible to turn e.g. the five fingers of an edge stitched glove, the fingers being turned one by one, each time with a safely established tightness between the finger opening and the mouth of the nozzle tube 12. Thus, with the use of this nozzle tube it is possible to turn the fingers of a whole series of newly produced gloves, and if the remaining final turning of the gloves cannot easily be done manually, then it is a further possibility to thereafter change the nozzle tube 12 for a broader tube that can cooperate with the root portion of the entire glove, for successive final turning of all the gloves of the said series of gloves.

Alternatively, as shown in Fig. 2, the tube 8 may be provided with two different nozzle tubes 12 and 12'' connected in parallel through respective valves 14 and 14', which, by suitable control means, can be selective¬ ly actuated. Hereby it will be possible to carry out a partial turning of the workpiece, e.g. the said glove fingers, on one nozzle 12, and immediately thereafter a final turning of the same workpiece with the use of the other nozzle 12', whereafter the narrow nozzle 12 can

again be selected for operative use.

It is a surprising result that even stiff working gloves can be turned in the disclosed manner. Even at full vacuum the suction or turning pressure can be only one bar, but this has been found sufficient. On the other hand, the high vacuum may be directly damaging for less stiff workpieces, and when it is actual to also handle that kind of workpieces it will be highly advan¬ tageous that by means of the adjustment valve 18 it is possible to reduce the vacuum.

While in Fig. 1 a high vacuum is maintained in the large vacuum tank 6 the embodiment according to Fig. 3 will operate without such a large tank. In this embodi¬ ment the nozzle adaptor 10 is connected with a cylinder 22, in which a piston 24 is arranged so as to be driven through a connector rod 26 from a flywheel 28, this wheel itself being driven by a motor 30 and provided with a clutch unit 32 that can be actuated from the outside for coupling together the flywheel and the piston or connector rod 26 in a manner such that the piston 24 will then be rapidly retracted in the cylinder 22.

Hereby a strong vacuum will be applied on the nozzle tube 12 through the adaptor 10, widely corre¬ sponding to the above connection with the vacuum tank 6. The piston 24 is shown to have a one way valve 36 that will allow a throughflow of air by the upward stroke of the piston, just in case the turned workpiece has not been removed from the turning nozzle when the piston is moved up to its initial position, i.e for counteracting a return blowing of the turned workpiece.

Also in this embodiment, which should be designed to produce a very strong vacuum, a vacuum limiting valve 18 may be used.

In special productions, where all the workpieces can be turned by a vacuum of e.g. 80%, the apparatus

will of course not have to be designed for producing a full vacuum, and in Fig. 1. a corresponding pressostat control of the vacuum pump could be used. Besides, such a control can be used in stead of the valve 18. With the invention, generally it is relevant to make use of a suction in the range of 50-100% vacuum, which is con¬ siderably higher than achievable by usual suction blowers, where some 10% will be an operative maximum.

In Fig. 3 there is additionally shown a regulator valve 38 for the applied vacuum. As mentioned, the oper¬ ational vacuum should be high, but workpieces may occur which can hardly resist such a high vacuum, and the regulator valve may then be used to ascertain that a reasonably restricted vacuum is applied.

A further possibility will be to adjust the stroke length of the working piston by a differentiated coupling in thereof relative to the driving system used, e.g. the flywheel shown, such that by each turning oper¬ ation there will not be spent more energy than actually required.

The said piston can be moved by driving means other than a flywheel, e.g. in being retracted electromagneti- cally or by means of a driving system based on com¬ pressed air mounted in parallel with the operational system and, by virtue of a high overpressure, designed to force the piston rapidly downwards. The invention also comprises the disclosed method of carrying out the turning operations.