ECHNICAL FXEl^P

The present invention relates to a device for releasably clamping an object, such as a workpiece, said device comprising a main part or a base part in which there is provided at least one groove which is able to enclose a screw, and a clamping jaw which coacts with the screw such that rotation of the screw will cause the jaw to move towards or away from an inwardly facing end-part of the screw along the main part of said device, and wherein that end of the screw which is located adjacent said inwardly facing end-part is provided with or formed as a first part of a locking device which comprises at least two parts and which prevents movement of the screw along the groove.

DESCRIPTION OF THE PRIOR ART

The German Patent Specification 302,248 teaches a vice which includes a rotatable screw and a jaw coacting with the thread of said screw, and which are firmly connected through the medium of a nut arrangement in a manner which enables the jaw and the screw to be readily removed, so as to form a structure which is fixed in relation to the main part or base part of the vice.

The U.S. Patent Specification 1,966,338 teaches a clamping device, such as a vice, which includes four jaws which each coact with a respective screw and which further includes a centrally positioned gear wheel arrangement which when one of the screws is rotated functions to cause corresponding rotation of the remaining screws.

In this case, movement of the jaws and positioning of the screws are located within one and the same plane at right angles in relation to one another.

Further examples of the known prior art are described and illustrated in U.S. Patent Specification Nos. 1,342,891 and 1,490,608.

DISCLOSURE OF THE INVENTION

TECHNICAL PROBLEMS

When considering the earlier state of the art as described above, it will be seen that a technical problem resides in providing a clamping device of the kind defined in the introduction in which a first part of a locking device which is intended to hold a screw with coacting jaws and which is formed on the end-part of the screw is so constructed that in coaction with or in the lack of coaction with a simple second part can take a locking or a non-locking position solely in response to simple linear movement of the second part of the locking device.

It will be seen that a technical problem also resides in the provision of a locking device which, in principle, is comprised of only two parts, where one part (the first part) is secured to or formed on one end-part of the screw or screws, and where the second part shall be formed separately so that it can be brought into common coaction with at least two of said first parts in response to a simple linear movement or rotational movement in a direction at right angles to the centre line of the screw.

It will also be seen that a technical problem resides in realizing the significance of enabling a locking device

of the kind intended to be readily supplemented in a manner to enable a plurality of such screws to be locked simultaneously in addition to one or two screws with associated jaws.

It will also be seen that a technical problem resides in realizing the significance of and the simplicity of a locking device that is obtained when the second part of the device includes at least one peripheral edge-part which, in practice, is provided with a number of recesses which correspond to the number of screws and their orientation, and wherein these recesses are mutually so dimensioned and adapted as to enable them to embrace a web with a close fit and partially in the form of a "U" , formed in the end-part of respective screws and located adjacent to or forming said inwardly facing end-part.

It will also be seen that in the case of a locking device of this kind with which one or more of the aforesaid technical problems have been successfully solved, a technical problem resides in the ability to provide conditions which will allow the clamping force acting on the object clamped between the jaws and therewith acting in mutually opposite directions on the screw and jaw to be so adapted and aligned as to enable the second part of the locking device to be locked to the first part of respective screws.

It will also be seen that a technical problem resides in realizing the significance of giving the second part a simple configuration and to provide said part with a circular peripheral edge-part which can readily coact with a recess of slightly larger diameter in the main part.

Another technical problem resides in realizing the advantages afforded by the fact that when a second part is configured in the aforesaid manner, respective screws can be provided with a gear wheel in a known manner and that this gear wheel can be caused to coact, either directly or indirectly, with respective gear wheels on adjacent screws, so that rotation of one screw and one gear wheel will cause remaining screws to rotate, and therewith to realize that these gear wheels can be readily accommodated and covered by the second part of the locking device.

It will also be seen that a technical problem resides in realizing the significance of introducing between the inwardly facing end-parts a stop means which will function to bring respective screws and their respective first parts of the locking device to a predetermined positional setting in relation to the groove and the main part, and that this position can be adapted for direct coaction between the second part of the locking device and the first part of respective screws.

Furthermore, it is proposed that respective screws and their associated jaws can be inserted into respective grooves from outside the main part and in a direction towards the centre of said main part.

SOLUTION

The present invention is intended to provide a solution to one or more of the aforesaid technical problems and to this end takes its starting point from a device which is adapted to releasably secure an object, such as a workpiece, said device comprising a main part which includes at least one, preferably two straight grooves which are conveniently orientated in the extension of one another and each of which is capable of enclosing a

screw-threaded, rotatable screw and a jaw coacting with the thread of the screw, wherein rotation of the screw causes the jaw to move in towards or away from one end- part of the screw, and wherein each of the screws is provided at said one end thereof with or coacts with a first part of a locking device which comprises at least two parts and which prevents movement of the screw along the groove.

In accordance with the present invention, it is proposed that in an arrangement of this kind a second part of the locking device is adapted to be brought to locking coaction with at least one, preferably at least two screws belonging to said first part and out of locking coaction with said screws in an opposite direction when said second part is moved or rotated in a direction at right angles to the centre line of the screw.

According to proposed embodiments which lie within the scope of the invention, the number of grooves in the main part and associated screws and jaws may be two, three, four or six.

It is also proposed that the second part of the locking device shall include a peripheral edge-part in which there is formed a number of recesses corresponding to the number of grooves or screws, these recesses being positioned for coaction with screws and associated jaws and adapted to embrace a web formed in the end-parts of respective screws with a small clearance and in a U- shaped fashion.

It is also proposed in accordance with the invention that the clamping force acting on said object or said workpiece shall produce a reaction force which acts on respective screws and jaws and which is adapted and

applied to lock the second part of the locking device to each of said first parts.

According to one particular embodiment, the second part is provided with a circular, peripheral edge-part which in other regards has a thickness and a dimension which will enable it to coact with a corresponding recess in the main part, with a small clearance between said edge- part and the recess.

According to the invention, respective screws can be provided adjacent said first part with a gear wheel which will coact with gear wheels on adjacent screws, either directly or indirectly, wherewith rotation of one screw in one direction to displace the jaw in one direction causes remaining screws and jaws to rotate in the same direction.

It is also proposed in accordance with the invention that a stop is provided between the inwardly facing end- parts, this stop functioning to bring respective screws to a predetermined positional setting in relation to the main part and the grooves provided therein, this positional setting being intended for direct coaction between the second part of the locking device and the first part of respective screws.

In this case, respective screws and jaws can be inserted into respective grooves from outside the main part and in a direction towards the centre of said main part.

ADVANTAGES

Those advantages primarily afforded by an inventive arrangement reside in the fact that the clamping device can include a simple locking device for all screws with associated jaws, and in that the locking device is so

constructed that one single element (a second part of the locking device) is able to lock all screws with associated jaws and the first part of the locking device against movement in relation to the main part in a predetermined position solely by displacing said element in one direction at right angles to a centre line of respective screws, so that movement of the element in one direction will bring the locking device to an active position while movement in an opposite direction will bring the locking device to an inactive position. When the locking device is inactive, the screws and associat¬ ed jaws can be easily removed and replaced with other screws and associated jaws.

The main characteristic features of an arrangement constructed in accordance with the present invention are set forth in the characterizing clause of the following Claim 1.

BRIEF DESCRIPTION OF THE DRAWING

An exemplifying embodiment at present preferred and having characteristic features significant of the present invention will now be described in more detail with reference to the accompanying drawing, in which

Figure 1 is a perspective view of an inventive clamp¬ ing arrangement comprising one single screw and one clamp inserted in one of four grooves and shows a second part of a two-part locking device in an inactive lock¬ ing position;

Figure 2 is a side view of a screw with associated jaw;

Figure 3 is a sectional view of the central part of a main part of the clamping arrangement and shows an alternative embodiment of the lock¬ ing device; and

Figure 4 is a sectional view corresponding to the view of Figure 3 illustrating a further embodiment of the locking device.

DESCRIPTION OF A PROPOSED EMBODIMENT

Figure l illustrates in perspective a clamping device 1 by means of which an object, a workpiece or the like can be clamped in a readily released fashion. Although not shown, it can be assumed to take-up a surface 2 on a flat upper surface 3' of the main part 3. The object concerned may advantageously be an object which is to be worked or machined.

The clamping device l is comprised of a main part or a base 3 which is provided with a number of grooves, normally at least two grooves. In the illustrated embodiment, four grooves are provided.

The grooves shown are referenced 3a, 3b, 3c and 3d, although since the mutual positioning of the grooves and their cross-sectional shapes are identical to one another, the following description is restricted to solely the groove 3a, and to some extent also the diametrically located groove 3c.

Each of the grooves 3a-3d has an inverse T cross- sectional shape, so as to enable each groove to coact with a respective jaw 5 which has an inverse "T" shaped

part and a clamping part 5c arranged for movement over the upper surface 3' of the main part.

The groove 3a is configured so as to be able to enclose a screw or screw 4 and a jaw 5 coacting with the thread 4a of the screw.

The groove 3c is also configured so as to be able to enclose a screw and a jaw coacting with the thread of the screw. The screw and the jaw are not shown, how-ev- er.

It will be seen from Figure 1 that the groove 3a is formed in the main part 3 so that an inwardly facing end-part 3a' of the groove will be located in the proximity of the end-part 3c' of the groove 3c, and that the two grooves open into an inner, circular aperture 6.

As the screw 4 is rotated, with the aid of a pin 4b, the jaw 5 moves inwardly towards or outwardly away from the inwardly facing end-part 3a' or the aperture 6, in a known manner.

Each of the screws, such as the screw 4, is provided on the end 4' thereof that can be located adjacent the inwardly facing end-part 3a ' with a first part 7 of an at least two-part locking device which functions to prevent movement of the screw 4 and the jaw 5 along the groove 3a when in its inactive position, shown in Figure 1.

The second part 8 of the locking device has a circular shape and can be inserted into the aperture 6 with a small clearance, for coaction with the aperture. The second part 8 of the locking device is constructed so that when moved in a direction "P" at right angles to the centre line 4c of a screw 4, it can be brought to an

active position in which it coacts with at least one, although preferably more than two screws or grooves belonging to respective first parts 7 of the locking of the locking device and disposed at different or other angular positions.

The part 8 of the illustrated embodiment is provided with an angled groove 10', which enables the aforesaid locking effect to be achieved by displacing and rotating the part 8.

Normally , the number of grooves 3a, 3b, 3c, 3d will be more than two, and it is preferred that three, four or six grooves are provided in practice. A screw with associated jaw supported against a fixed support may also be used.

The second part 8 of the clamping device has a periph¬ eral edge-part 8a which includes a number of U-shaped recesses 10. The number of recesses and their positions around the edge-part 8a correspond to the number of grooves 3a-3d, or preferably to the number of screws 4. Each recess 10 is intended to coact with the first part 7 of the screw 4 and the edge-part has a thickness which conforms to the thickness of the web 11 of the first part 7.

The U-shaped recess 10 is intended to embrace the web 11 formed in the end-part 4' of respective screws 4 and located adjacent said inwardly facing end-part 3a' , with a small clearance between the recess and said web.

It will be understood that the clamping force which acts on respective screws and jaws as a reaction force will be so adapted with regard to direction and magnitude as to clamp and lock the second part 8 of the locking device to respective first parts 7 of said device.

Normal dimensioning and adaptation is required to this end.

The screw 4 can be provided adjacent said first part 7 with a bevel gear 12 which coacts, either directly or indirectly, with a gear 12' for an adjacent screw or screws coacting with the grooves 3b and 3d, wherein rotation of the screw 4 will cause remaining screws to rotate in a corresponding fashion.

Figures 3 and 4 illustrate alternative embodiments of the centrally located locking device, among other things.

As will be seen from the Figures, the central aperture 6 in the main part 3 is sealed at its lower part by a guide plate 16 having a centrally positioned part 11 around which a guide ring 12 is fitted.

A centre plate 13 or the second part of the locking device could be removed and take an inactive locking position.

The invention provides the simple possibility of forming in an inactive position between the inwardly facing end- parts 4' a stop adjacent the guide ring 12 which is intended to bring the end-parts 4' of respective screws to a predetermined positional setting in relation to the groove and the aperture 6. This positional setting shall be adapted to afford direct coaction between the first parts 11 of the locking device and the second part 13 of the locking device, meaning that the web 11 will take a position which enables the recess 10 to be brought into direct coaction with the web 11 with a slight clearance therebetween, by virtue of the width of the recess.

When the second part 8 of the locking device is in the upper, inactive position shown in Figure 1, respective screws 4 and their associated jaws 5 can be inserted and withdrawn through the groove 3a from outside the main part 3 and in a direction towards and away from the centre of the main part.

When the centre plate 13 occupies the position illus¬ trated in Figure 3, the edge-parts 8a' will block movement of the screw 4 to the left in Figure 3.

The centre plate 13 can be secured to the guide plate 16 with the aid of a centrally positioned screw fastener forming a third part of the locking device, although this is not shown.

It will be noted that in the case of this embodiment, rotation of one screw 4 will not influence the other screws.

Figure 4 illustrates a further embodiment in which a bevel gear 12 meshes with a rotatable bevel gear 14 which, in turn, meshes with other gears on remaining screws. A centre plate 13 (a part 8 belonging to the locking device) has edge-parts 8a' which block movement of the screw 4 and remaining screws away from the centre 3".

Although not shown, the centre plate 13 can be fastened to the guide plate 16 with the aid of a centrally positioned screw fastener.

The jaw 5 includes a hole 5a which has a screw-thread 5a' corresponding to the thread 4a of the screw 4, a web 5b which fits through the narrow part of the groove 3a, and a jaw part 5c having a jaw surface 5c' which is intended to abut the object to be worked.

It will be understood that the invention can be imple¬ mented in many other ways than that described and illustrated.

For instance, the main part 3 may be provided with a permanently fixed jaw or support and one single screw carrying a jaw which moves towards and away from the fixed support, or alternatively two or more screws with jaws that move towards and away from said fixed support.

In practice, the most convenient application is one in which the angular distance between the grooves conforms to the formula 360°/n, where "n ⁿ is one of the discrete values 2, 3, 4 or 6 with symmetrically disposed grooves and jaws.

It will be understood that the invention is not re¬ stricted to the aforedescribed and illustrated exem¬ plifying embodiments thereof and that modifications can be made within the scope of the invention as defined in the following Claims.