PNEUMATIC VISE WITH HYDRAULIC FORCE AMPLIFIER

Abstract: The invention relates to a vise operated by compressed air as a transmitter of input pressure force and hydraulic oil as a means for amplifying same, with a respective assembly for amplifying the input pressure force residing within the area of a stationary vise jaw. According to the invention, a pneumatic/hydraulic assembly (4) as a unit for amplifying the input pressure force provides a pneumatic piston (16), whose power stroke is directed against the power stroke of a shiftable vise jaw (3), and a hydraulic piston (11), whose power stroke is synchronous and coinciding with the power stroke of said shiftable vise jaw (3). By a shaft piston (15) the force of the pneumatic piston (16) is conveyed into hydraulic oil. The pressure generated in hydraulic oil by said shaft pis ton (15) is conveyed onto a working area of the hydraulic piston (11). The force of the latter is the spanning force of said shiftable vise jaw (3).

Description: PNUEMATIC VICE WITH HYDRAULIC FORCE AMPLIFIER The invention relates to a vise operated by compressed air as a transmitter of an input pressure force and hydraulic oil as means for amplifying same, with a respective assembly for amplifying the input pressure force residing within an area of a stationary vise jaw. Vises of the type specified above are widely known from the market. Besides, patents GB 1,450,505, CH 677.748, US 3,359,728, DE 26 26 557, DE 44 05 935 and DE 37 33 849 have been considered as technological background when creating the present invention. It is a basic object of the present invention to provide a compressed-air/hydraulic-oil vise, specifically a vise of the kind set forth above in the introductory section, which will make possible any desired aggregation of the vises to assemblies of parallel vises arranged either in horizontal configurations or in vertical ones as well as either in two- dimensional arrangements or in three-dimensional ones, without any supply of compressed air at the end of the vise having a shiftable jaw and resulting in great spanning forces in small vises. According to the invention the above object is achieved by the following constructional features. A pneumatic/hydraulic assembly (PHA) as a unit for amplifying an input pressure force provides a pneumatic piston, whose power stroke is directed against the power stroke of a shiftable vise jaw, and a hydraulic piston, whose power stroke is synchronous and coinciding with the power stroke of said shiftable vise jaw. According to the invention said pneumatic section and said hydraulic section of the assembly for amplifying the input force of the vise are united to a single construction. A shaft piston is added to said pneumatic piston on the side opposite to the working face thereof, the shaft piston being preferably integral with the pneumatic piston. A force generated by compressed air on the pneumatic piston i.e. a piston of a greater working area, is thus exerted by this piston by means of a piston providing a smaller working area. A vise stud is added to said hydraulic piston on the side oriented to the shiftable vise jaw, said vise stud being preferably integral with the hydraulic piston. The vise stud is a member of the vise for conveying the force of said hydraulic piston to a vise spindle. Said hydraulic piston provides an axial central hole on its side oriented to said shaft piston, said axial central hole extending, by an appropriately enlarged diameter, into the area of the vise stud to form a cylindrical hydraulic chamber. At least two traverse passages for conveying hydraulic oil are foreseen in the respective wall sections of the vise stud and the hydraulic piston between said cylindrical hydraulic chamber and an outer annular corner created by the vise stud and the hydraulic piston. An axial passage is foreseen in the pneumatic piston and shaft piston, said passage being releasably sealed on the pneumatic-piston side, suitably by a screw plug. Said shaft piston cooperates with said central axial hole and said hydraulic chamber of the hydraulic piston/vise stud, respectively. Said passage of the shaft piston, the hydraulic chamber of the hydraulic piston/vise stud, said traverse passages and a chamber of the PHA created on the working side of the hydraulic piston are filled up with a hydraulic oil, which, in this position, constitutes a constructional member of the vise. A pressure spring is inserted between the pneumatic piston and the hydraulic piston, which works as a return spring when compressed air has been released. Said vise spindle is mounted onto the vise stud preserving the freedom of rotation. An outer end of the vise spindle is constructed (in a known manner) as a drum-shaped knob that creates, on its outer mantle surface and in combination with the vise spindle, an annular shoulder for retaining a supporting pressure spring accommodated in a (known) vise yoke and, on its inner mantle surface, an annular shoulder for taking up the axial pressure force of the vise stud. Hereinafter, the invention is disclosed in detail by way of an example of an embodiment shown in the annexed drawing, in which a single Figure shows an elevational view of a vertical central longitudinal section of a horizontally installed vise of this invention in its stand-by state. The vise comprises a vise bed 1 with its outer design being substantially a parallelepiped block, basically of a channel section, whose side pieces (stands) support, at one end of said block, a stationary vise jaw 2, said stationary vise jaw 2 being suitably connected with said side pieces of the vise bed 1 to constitute an interconnection thereof. The remaining portion of the upper surface of said vise bed side pieces carries a shiftable vise jaw 3 also guided thereby when moving. From the end of the vise bed 1 having the stationary vise jaw 2, a pneumatic/hydraulic vise assembly (PHA) 4 is inserted into the cavity of the profiled vise bed 1 co-axially with it and fastened to it in a manner disclosed below. The PHA 4 consists of a housing 5, whose cross section is suitably, not obligatorily, designed in conformity with the cavity of the vise bed 1 into which it is incorporated. Basically, the housing 5 is a sleeve-type member having a (profiled) outer mantle surface and a stepped cylindrical inner cavity comprising a chamber 6, suitably of a larger diameter, and a further chamber 7 connected thereto, suitably of a smaller diameter. The housing 5 is oriented to provide an orifice of the chamber 6 open in the direction of the nearest end of the profiled vise bed 1. The housing 5 provides a bottom member 8 constituting a closing wall of the chamber 7. In the bottom member 8 a passage 9 is foreseen. From the side of the PHA 4, a vise stud 10 is inserted into the passage 9 of the bottom member 8 of the housing 5, constituting a central element of the vise for interconnecting the PHA 4 and the shiftable vise jaw 3. A piston 11 is inserted into the chamber 7. With respect to the bottom member 8 of the housing 5 of the PHA 4, the piston 11 determines a hydraulic working chamber 7a. As shown, the vise stud 10 and the piston 11 are suitably, not obligatorily, united to one element. The piston 11 provides a central axial hole 12, which is enlarged, on the side of the vise stud 10, to form a chamber 13 extending into the area of the vise stud 10 and annexed to the hole 12. In the wall section of the vise stud 10 providing the chamber 13 and/or in the piston 11, two or more substantially radial passages 14 are foreseen for interconnecting the chamber 13 and the mantle surface of the vise stud 10/piston 11 tandem member, suitably at the location of their meeting line i.e. in the annular corner. Thereby a communication between the chambers 7a, 13 is provided. From the side of the chamber 6 a shaft piston 15 is inserted into the hole 12 of the piston 11. Due to circumstances explained below, the shaft piston 15 is hollow so that it is basically a tube. Into the chamber 6 a disc-shaped piston 16 is inserted, which is centrally holed as well. Suitably, not obligatorily, the shaft piston 15 and the discshaped piston 16 are united to an element as shown and provide a common central passage 17. An orifice of the passage 17 residing on the outer side of the piston 16 is sealed - in the given embodiment - by a screwed plug 18. An expanding i.e. a pressure spring 19 is inserted between the pistons 11, 16. At its orifice the chamber 6 is sealed by a cover 20. With respect to the cover 20 of the PHA 4, the piston 16 defines a pneumatic working chamber 6a. Besides, the PHA 4 is fastened to the vise bed 1 by means of the cover 20, which is, to this end, suitably fastened to the front of profiled bed 1 with the contours of said bed and said cover corresponding to each other. The cover 20 provides a central threaded hole 21. A ventilating hole 6b for the chamber 6 is foreseen near the meeting point of the chambers 6, 7. At the other end of the profiled vise bed 1, i.e. opposite the PHA 4, a vise yoke 22 is incorporated between the side pieces (stands) of the bed profile. The yoke 22 provides a central axial hole 23 extending over a minor axial portion of the yoke and a central axial bearing 24 extending over a major axial portion of the yoke. The axial dimension of the vise stud 10 is sufficient for it to extend through the yoke 22. A significant clearance exists between the outer mantle surface of the vise stud 10 and the hole 23 of the yoke 22. From the side of the yoke 22, a tubular vise spindle 25 is put on the vise stud 10, the wall thickness of said spindle being adapted to the size of the above-mentioned significant clearance. On the prevailing portion of its length, the vise spindle 25 provides an outer thread co-operating with an internal thread of a carrier 26 of the shiftable vise jaw 3. In the area of the orifice of the yoke 22, the vise spindle 25 is flangedly widened to have the diameter of the bearing 24 so that between said flanged widening of the spindle 25 and the bottom member of the bearing 24 there exists an annular axial space occupied by an expanding i.e. pressure spring 27 being inserted therein. Between the spring 27 (being an element stationary with respect to rotation) and the flanged widening of the spindle 25 (rotary element) a thrust bearing is suitably inserted. The vise stud 10 terminates by a cylindrical prolongation member for the accommodation of a ring-type spacer 28 and by a threaded prolongation member to mount a screw nut 29. The outer diameter of the spacer 28 exceeds the diameter of the vise stud 10 so that the latter and the spacer 28 together create a chamber for accommodating a thrust bearing separating the vise stud 10 (stationary with respect to rotation) from the (rotary) spindle 25. In the area of the screw nut 29, the spindle 25 terminates by a drum-shaped knob 30. A charge of hydraulic oil not specifically shown in the drawing constitutes a constituent member of the proposed vise. In the state of vise as shown, the chamber 7a, the passages 14, the chamber 13 and the chamber 17 are filled up with hydraulic oil. To the threaded hole 21 there is connected a compressed air supply provided with a two-position ON/OFF controller (not shown) known per se. By rotating the knob 30 the carrier 26 of the shiftable vise jaw 3 is shifted along the spindle 25 either in one or in another direction with respect to the stationary vise jaw 2, thus adjusting the vise clearance A for applying a workpiece. For spanning the workpiece in the vise there is foreseen a working stroke B of the shiftable vise jaw 3. Thus, the extension (A - B) is the spanning extension of the workpiece. By the admission of compressed air (ON position) into the chamber 6a, air strikes against the piston 16, which begins moving along the chamber 6 to the left as according to the drawing. The tubular piston 15 functioning in the chamber 13 like a plunger drives hydraulic oil out of the chamber 13. This occurs on the account of the streaming of oil out of the chamber 13 through the passages 14 into the chamber 7a resulting in shifting the piston 11 along the chamber 7 to the right as according to the drawing. The spring 19 gets compressed. It is preferably foreseen that the mutual approaching of the pistons 16, 11 ends when the pistons have met. Since the vise stud 10 is connected to the piston 11, it moves together with it. At the same time, by means of the respective thrust bearing, the spacer 28 pushes the spindle 25 in front of itself, the spindle 25 towing the carrier 26 suspended onto it and thereby the shiftable vise jaw 3 annexed to it. The movement of thespindle 25 is accompanied by the compressing of the pressure spring 27 within the yoke 22. Obviously, this is a working stroke of the shiftable vise jaw 3 and it is adjusted to the extent of B. The input force of the vise is the force of compressed air acting on the piston 16. The force of the piston 16 equals the force of the piston 15 compressing hydraulic oil in the chamber 13. By means of the passages 14, oil pressure is also set up in the chamber 7a where oil acts onto the piston 11. The ratio of the working areas of the pistons 11, 15 and of the strokes of the pistons 15, 11 is a multiplier of the input vise force. By releasing compressed air (OFF position) from the PHA 4, the force acting on the piston 16 is eliminated. The accumulated energy of the pressure springs 19, 27 gets activated and said springs begin to restore the previous state of the PHA 4 and, finally, they restore it. The extent of the spanning force depends on the maximum allowable elastic strain of the workpiece. The extent of the working stroke of the vise jaw 3 i.e. the dimension of B is adapted thereto. A state providing a total compression of one of the springs 19, 27 is prevented by a pre-defined space between the inner base area of the spindle 25 and the opposed base area of the bottom member 8 of the housing 5 of the PHA 4.

Claims: C L A I M S 1. A vise operated by compressed air as a transmitter of input pressure force and hydraulic oil as a means for amplifying same, with a respective assembly for amplifying the input pressure force residing within the area of stationary vise jaw, characterized in that a pneumatic/hydraulic assembly (PHA) (4) as a unit for amplifying the input pressure force provides a pneumatic piston (16) with a power stroke being directed against a power stroke of a shiftable vise jaw (3), and a hydraulic piston (11), whose power stroke is synchronous and coinciding with the power stroke of the shiftable vise jaw (3). 2. The vise of claim 1, characterized in that a shaft piston (15) is added to the pneumatic piston (16) on the side opposite to a working face thereof, the shaft piston (15) being integral with the pneumatic piston (16). 3. The vise of claim 1, characterized in that a vise stud (10) is added to the hydraulic piston (11) on the side oriented to the shiftable vise jaw (3), the vise stud (10) being integral with the hydraulic piston (11). 4. The vise of claim 3, characterized in that the hydraulic piston (11) provides an axial central hole (12) on its side oriented to the shaft piston (15), the axial central hole (12) extending by an appropriately enlarged diameter into the area of the vise stud (10) to form a cylindrical hydraulic chamber (13). 5. The vise of claim 3 and 4, characterized in that at least two traverse passages (14) for conveying hydraulic oil are foreseen in the wall section of the vise stud (10) and of the hydraulic piston (11), between the cylindrical hydraulic chamber (13) and an outer annular corner created by the vise stud (10) and the hydraulic piston (11). 6. The vise of claim 2, characterized in that an axial passage (17) is foreseen in the pneumatic piston (16) and in the shaft piston (15), the passage (17) being releasably sealed on the pneumatic piston side, suitably by a screw plug (18). 7. The vise of claims 2 to 4, characterized in that said shaft piston (15) cooperates with the central axial hole (12) and the hydraulic chamber (13) of the hydraulic piston (l l)/vise stud (10). 8. The vise of one of the preceding claims, characterized in that the passage (17) of the shaft piston (15), the hydraulic chamber (13) of the hydraulic piston (ll)/vise stud (10), the traverse passages (14) and a chamber (7a) of the PHA (4) created on the working side of the hydraulic piston (11) are filled up with hydraulic oil. 9. The vise of claim 1, characterized in that a pressure spring (19) is inserted between the pneumatic piston (16) and the hydraulic piston (11). 10. The vise of claim 3, characterized in that a vise spindle (25) is mounted onto the vise stud (10) preserving the freedom of rotation. 11. The vise of claim 10, characterized in that the outer end of the vise spindle (25) is constructed as a drum-shaped knob (30) that creates, on its outer mantle surface, in combination with the vise spindle (25) an annular shoulder for retaining a supporting pressure spring (27) accommodated in a vise yoke (22) and, on its inner mantle surface, an annular shoulder for taking up the axial pressure force of the vise stud (10).

Inventors: PIVK JOZE, PIVK, JOZE
Applicants: PIVK JOZE, PIVK, JOZE
Application year: 2000
Main classification: B25B1
IPC codes: B25B1