GB2125073A - Clamping frame in embroidering and sewing machines - Google Patents

Abstract

The invention is for a quick- change clamping frame for embroidering and sewing machines, preferably multi-head automatic embroidering machines with holding straps 2 disposed on opposite sides of the base portion 1 of the frame, of which straps at least one is provided with a two-part spring loaded clamping device for the removable fixing of the clamping frame on one 4 of two mounting supports 3, 4 connected with the pantograph of the machine. One of the mounting supports 4 is designed with a longitudinal slit 6 and the other 3 with a transversal slit 5 for pushing in a pin 8 in each case. To simplify handling, the rear edge of the transversal slit, is extended by a limiting edge 13, whilst the longitudinal slit is provided with a funnel-shaped widening 14. The guiding length of the outer part of the widening 14 corresponds to at least the length of the limiting edge, while the guiding length of the inner part of the widening corresponds to at least an excess length designed in the transversal slit. <IMAGE>

Description

SPECIFICATION Quick-change clamping frame for embroidering and sewing machines The invention relates to a quick-change clamping frame for embroidering and sewing machines, preferably multi-head automatic embroidering machines with holding straps disposed on opposite sides of the base portion of the frame, of which straps at least one is provided with a two-part spring-loaded clamping device for the removable fixing of the clamping frame on one of the two mounting supports connected with the pantograph of the machine, one of the mounting supports being designed with a longitudinal slit and the other with a transversal slit for pushing in a pin in each case.

In order to be able to fix interchangeable embroidery frames on the pantographs of embroidering or sewing machines, various constructions are now known. Apart from mounting supports at the rear of embroidery frames, which supports are used preferably on machines with a high number of heads because of the limited space requirements, lateral mounting supports are known.

German Utility Model Specification 1 894 1 62 shows a quick-change clamping frame of the type first defined hereinabove which is connected by means of lateral mounting supports with the pantograph of the machine. Such quick-change clamping frames are made in all shapes and sizes and used in practice with success.

Although the mounting of the known quickchange clamping frames on the mounting supports of the machine requires only some three seconds, the claim has been laid to shorten the time for the fixing of the quick-change clamping frames on the mounting supports, and at the same time to improve handling in such a manner that the putting on and removal of the clamping frame on the mounting supports can be done with one hand and without close watch. To an increasing extent, as dictated by fashion, textile underlays are used as embroidering background which hang over extensively over the clamping frames and their mounting supports, such as, e.g.

table cloths, handkerchiefs, cuts of blouses or shirts. By this extensively overhanging background for embroidery, the view of the mounting supports provided with slits and of the pins to be pushed in on the holding straps of the clamping frame is obstructed. With the known clamping frames the operator is therefore compelled, before placing the clamping frame in position, to throw back the overhanging embroidery background if he is to avoid tedious feeling about for the start of the slits.

The invention has for its object to obviate these drawbacks and to provide a quick-change clamping frame of the type first defined hereinabove which can be mounted with in a considerably shorter time on the mounting supports of the pantograph, this being effected also when embroidery background overhangs and preferably with one hand.

The achievement of this object by means of the invention is characterised in that the rear edge of the transversal slit is, in one mounting support, extended into a limiting edge, and in that the longitudinal slit provided in the other mounting support is provided with a funnel-shaped widening.

By means of this further embodiment according to the invention it is achieved that the quick-change clamping frame is led with one pin from the front only onto the limiting edge before the transversal slit, and subsequently, with the other pin, it has to be applied onto the funnelshaped widening before the longitudinal slit in order, by a subsequent pressing of the clamping frame, to achieve an automatic in-sliding of the two pins in their respective slits. This handling may be carried out blindly, i.e. without observation of the pins and mounting supports, also with one hand, so that the placing on of the clamping frame is not hindered either by the overhanging of the material for embroidering.

Tests have shown that the quick-change clamping frame according to the invention can be mounted on the mounting supports of the pantograph within a time of only one second, so that, in addition to simplification, a considerable time saving is achieved.

These considerable advantages of the invention may be achieved with simple constructive means which, in addition, permit the use of quick-change clamping frames according to the invention on mounting supports of existing embroidering and sewing machines as weil as of existing quick-change clamping frames on mounting supports constructed according to the invention.

According to a further feature of the invention the guiding length of the widening provided on the externally-placed leg of the mounting support corresponds at least to the length of the limiting edge, and the guide length of the widening provided on the internally-placed leg at least to one excess length made in the transversal slit. By this means it is assured that the funnel-shaped widening introduces the relevant pin reliably into the longitudinal slit of the mounting support, and that with an excess length of the transversal slit the different distances between the pins arranged on the holding straps do not result in an obstacle to satisfactory performance.

While with the known quick-change clamping frames two-part spring-loaded clamping devices are used on both holding straps, it is possible as a simplification, according to a further feature of the invention to provide only one holding pin on the holding strap cooperating with the mounting support with transversal slit. This holding pin is sufficient for a proper fastening of the clamping frame, so that it is possible to save one clamping device.

According to a further feature of the invention, on the holding strap cooperating with the mounting support with longitudinal slit, at least one clamping device is arranged which, in known manner, consists in a guide pin fixed on the holding strap with a superimposed upper portion and a bottom portion which can be raised relative to the guide pin against the force of a spring. The bottom portion and upper portion of the clamping device are preferably made of plastic, this being done by simultaneous spraying of plastic around the guide pin.

The bottom portion of the clamping device is further provided, in per sue known manner, with a guide cone which can engage by spring action into a conical recess of the mounting support provided with the longitudinal slit. In a further embodiment of the invention the conical recess is formed on an attachment surrounding the bottom of the longitudinal slit. This attachment is, according to further features of the invention, mounted on the mounting support, preferably rivetted and provided with inclined ramps which, on pushing in the guide pin into the slit support a lifting of the bottom portion against the upper portion of the clamping device, or effect such lifting automatically, so that the clamping device must be fully actuated only on the removal of the quick-change clamping frame. Preferably, the attachment is made of a plastic able to slide freely.

Represented on the drawing are two examples of embodiment of the quick-change clamping frame according to the invention, wherein Fig. 1 shows a top view of a clamping frame on being positioned on the mounting supports; Fig. 2 shows a top view corresponding to Fig. 1 in positioned condition; Fig. 3 shows a front view of Fig. 2 with a clamping device represented in cross-section; Fig. 4 shows a perspective view of the mounting support provided with the longitudinal slit, and Fig. 5 shows a front view corresponding to Fig.

3 of a second form of embodiment of the clamping frame.

The quick-change clamping frame represented on the drawing as an example of embodiment comprises an annular frame bottom section 1, which may be constructed not only circular, but also oval or elliptical or in any other desired shape. To this frame bottom section 1 the material for embroidering is clamped by means of a frame upper section which has not been represented on the drawing for the sake of greater clarity.

The frame bottom section 1 is provided on opposite sides with holding straps 2 which carry in each case a pin which cooperates with a slit in the mounting supports 3 and 4, said supports being connected with the pantograph of the machine concerned and accordingly, correspondingly with the controlling of the machine, are moved to form the pattern. As shown in particular by Fig. 1, the mounting support 3 is provided with a transversal slit 5, and support 4 with a longitudinal slit 6.

The pins cooperating with these slits 5 and 6 of the clamping frame are, in the example of embodiment according to Figs. 1 to 4, constructed as guide pins 8 of a clamping device 7 which is represented in longitudinal section in the right-hand part of Fig. 3.

This representation shows that the guide pin 8 is, over a threaded attachment 8a and with the aid of a threaded bush 8b, screwed by means of a nut Sc onto the underside of the holding strap 2 and extends upwards through an aperture in the holding strap 2. On the upper end of the guide pin 8 an upper portion 9 is disposed which is made preferably of plastic. On said upper portion 9 or the guide pin 8 there is passed furthermore, in movable manner, a bottom portion 10 which may also be made of plastic. Between the upper portion 9 and the bottom portion 10 a spring 11 is disposed which, in the example of embodiment, is constructed as a spiral spring passed onto the guide pin 8.This spring 11 which rests by its upper end on the upper section 9 and by its lower end on the bottom section 10, effects that the bottom section 10 is always loaded in the direction of the holding strap 2.

The bottom section 10 of the clamping device 7 is provided with a guide cone 1 0a which cooperates with a corresponding conical recess 1 2a which is provided on the mounting support 4.

In the example of embodiment represented the conical recess 1 2a is formed on an attachment 12 surrounding the bottom of the longitudinal slit 6.

This attachment 12 which preferably is made of plastic is, in the first example of embodiment, fixed on the upper side of the mounting support 4, e.g. by rivetting. As particularly Fig. 4 shows, the attachment 12 has, in addition to the conical recess 1 2a, inclined ramps 1 2b, which cooperate with the underside of the bottom section 10, in order to lift the latter on the introduction into the longitudinal slit 6 against the force of the spring 1 so that by its guide cone 1 0a it engages properly into the conical recess 1 2a of the attachment 12.

According to Figs. 1 and 2 the rear edge of the transversal slit 5 in the mounting support 3 is extended by a limiting edge 1 3 which therefore along a section of the width forms the forward front surface of the mounting support 3. The longitudinal slit 6 formed in the mounting support 4 is provided with a funnel-shaped widening 14 which in the example of embodiment has been constructed symmetrically. The guide length of the widening 14 corresponds at least to the length of the limiting edge 13 or the excess length of the transversal slit 5.

To introduce the clamping frame by means of its guide pins 8 into the slits 5 and 6 of the mounting supports 3 and 4, the frame bottom section 1 provided with the stretched and sometimes overhanging material to be embroidered, is laid before the mounting supports 3 and 4 on the embroidery table, the two clamping arrangements 7 lying at a suitable height in respect of the mounting supports 3 and 4. The overhanging material to be embroidered is-as far as necessary-rolled up together from the sides; however it does not require to be thrown back over the clamping devices 7.

Subsequently, the left guide pin 8, according to Fig. 1, is pressed against the limiting edge 1 3 of the mounting support 3, and the right guide pin 8 is pressed into the funnel-shaped widening 14 of the mounting support 4. A further pressing with a left-ward movement then provides for the proper insertion of the left guide pin 8 into the transversal slit 5 of the left mounting support 3, and of the right guide pin 8 into the longitudinal slit 6 of the right mounting support 4. On this entry of the right guide pin 8 into the longitudinal slit 6 the inclined ramps 1 2b of the attachment 12 lift the bottom section 10 of the clamping arrangement against the action of the spring 11.

As soon as the guide cone 1 0a lies properly above the conical recess 1 2a of the attachment 12, the bottom section 10 is pressed downwards by the spring 11. By this means there is effected the desired position fixing of the right clamping arrangement 7 on the mounting support 4 which in respect of the left mounting support 3 is effected by the setting of the guide pin 8 in the transversal slit 5.The clamping frame has then assumed the position represented in Fig. 2, in which the working process can begin. To remove the quick-change clamping frame it is only necessary to lift with one hand the bottom section 10 of the right clamping arrangement 7 against the force of the spring 11 with its guide cone 1 0a out of the conical recess 1 2a of the attachment 12 and, by means of the right clamping arrangement 7 to pull out the holding strap 2 forward out of the longitudinal slit 6 of the mounting support 4. In this operation the guide pin 8 of the left clamping arrangement 7 glides automatically out of the transversal slit 5 of the left mounting support 3, so that the clamping frame may be taken off forward quickly and without difficulty, within the shortest time, from the mounting supports 3 and 4.

As will be appreciated from the foregoing considerations, it is not necessary to use both hands for the placing and removal of the clamping frame. The double arrangement of the clamping device 7 in the example of embodiment according to Fig. 1 to 4 is provided only so that the two holding straps 2 can cooperate with the mounting support 4 provided with the attachment 12. Also, a frame bottom section 1 rotated to 180 can therefore be set on the mounting supports 3 and 4.

In the second example of embodiment according to Fig. 5 the left clamping arrangement 7 is replaced by a simple holding pin 15, which is slighly longer than the thickness of the mounting support 3. It is thus protruding above the holding strap 2 only to the extent that on normal embroidering it cannot slide out of the transversal slit 5 of the mounting support 3 downwards. In order to prevent injury to the operator or damage to the material for embroidery the holding pin 1 5 has preferably a rounded dome.

Claims (9)

Claims

1. Quick-change clamping frame for embroidering and sewing machines, preferably multi-head automatic embroidering machines with holding straps disposed on opposite sides of the base portion of the frame, of which straps at least one is provided with a two-part springloaded device for the removable fixing of the clamping frame on one of the two mounting supports connected with the pantograph of the machine, one of the mounting supports being designed with a longitudinal slit and the other with a transversal slit for pushing in a pin in each case, characterized in that the rear edge of the transversal slit (5) is, in one mounting support (3), extended into a limiting edge (13), and in that the longitudinal slit (6) provided in the other mounting support (4) is provided with a funnelshaped widening (14).

2. Quick-change clamping frame according to Claim 1, characterized in that the guide length of the widening (14) provided on the externally-lying arm of the mounting support (4) corresponds at least to the length of the limiting edge (13), and the guide length of the widening (14) provided on the internally-lying arm correspdnds at least to an excess length provided in the transversal slit (5).

3. Quick-change clamping frame according to Claim 1 or 2, characterized in that a fixed holding pin (15) is provided on the holding strap (2) cooperating with the mounting support (3) with transversal slit (5).

4. Quick-change clamping frame according to Claims 1 to 3, characterized in that a clamping arrangement (7) is provided on the holding strap (2) cooperating with the mounting support (4) with longitudinal slit (6), which clamping arrangement (7) consists in a guide pin (8) with superimposed upper portion (9) fixed on the holding strap (2) and a bottom section (10) which can be raised relative to the guide pin (8) against the force of a spring (11).

5. Quick-change clamping frame according to Claim 3, characterized in that the bottom section (10) of the clamping device (7) is provided with a guide cone (10a) which can be engaged into a conical recess (1 2a) of the mounting support (4) through the action of a spring (1 1).

6. Quick-change frame according to Claim 5, characterized in that the conical recess (12a) is formed on an attachment (12) surrounding the bottom of the longitudinal slit (6).

7. Quick-change clamping frame according to Claim 6, characterized in that the attachment (12) is provided with inclined ramps (1 2b).

8. Quick-change clamping frame according to Claims 6 or 7, characterized in that the attachment (12) is made in a plastic with sliding properties.

9. A clamping frame substantially as herein described with reference to the accompanying drawings.