DESC:4. DESCRIPTION
Technical Field of the invention

The present invention relates to an Electro Permanent Magnetic work holding apparatus with a monolithic work face. More specifically, the invention relates to an Electro Permanent Magnetic (EPM) clamping apparatus consisting of a solid construction that eliminates the seepage of coolant water through its working face.

Background of the invention

Clamping of various work pieces is ever existing process in manufacturing industries. These clamping apparatuses generally operated with hydraulic or pneumatic clamps owning a moving piston and a fixed base is a known mechanism. Clamping of work pieces is attained by applying high pressure on the piston for effectively clamping the work piece.

Electro-permanent magnetic apparatuses are used for holding workpieces during machining, holding dies/molds in presses, lifting, transporting, etc. The magnetic circuit of an electro-permanent magnetic apparatus includes a permanent magnet that can be electrically switched between ON (magnetized) and OFF (de-magnetized) states, and once in either state, no further electrical energy is required to maintain the permanent magnet in that state. Once energized, the electro-permanent magnet can thus be disconnected from electrical power indefinitely without losing magnetic clamping power.

Electro Permanent Magnetic chuck has been used for clamping of ferromagnetic objects for very long time. Generally, these magnetic chucks have a ferrous body in which the reversible and/or non-reversible magnets and electrical coil(s) are placed. Furthermore, the body itself is a complete magnet. An additional laminated top plate is placed on top of the magnet to reduce the pole configuration making thinner components clamping easier.

In the following illustrations we would use the following words to explain the magnetic chuck.

Reversible magnet: These are generally soft magnetic material like AlNiCo etc., whose magnetic orientation can be changed using an electrical coil.

Non-Reversible magnet: These are generally hard magnetic material like NdFeB, SmCo, or StFe etc., whose magnetic orientation will not change during operation.

Fig. 1a illustrates a prior art magnetic clamping apparatus. The prior art magnetic clamping apparatus as shown in Fig. 1a comprises of a ferromagnetic bottom plate (10), and a reversible magnet (4) surrounded by a coil (6). On top of the reversible magnet (4) a ferromagnetic pole (7) is placed, and this is surrounded by non-reversible magnet (8). On top of this magnetic assembly, a laminated top plate (3) is placed.

The construction of a laminated top plate (3) is shown in fig. 1b, wherein the laminated top plate (3) consists of end bars (11) through which one or more non-magnetic tie rods (13) can pass through. The lamination consists of magnetic piece (4) and non-magnetic piece (8) like brass, aluminium, stainless steel or the like materials. The lamination is tightened with the help of nuts (12). Sometimes these tie rods are welded or brazed together. The complete laminated plate (3) is secured onto the magnet with the help of the bolts.

Fig. 1c illustrates another variation of the prior art, in this, the ferromagnetic frame (10) houses reversible magnet(s) (4) and the coil(s) (6). The laminated top plate (3) is placed on top of it directly. The empty area is filled up with filler material like epoxy/ resin etc. Sometimes, a metal thin sheet is placed in between the magnet (4) and the laminated top plate (3) to protect from water seepage.

The illustrated prior arts and similar apparatus have certain disadvantages like:
a) The laminated top plate is made with individual parts so there is an inherent gap between the pieces through which water can seep through.
b) Since lamination is done through a tie rod there is always a gap and due to the usage, the lamination can get distorted creating peaks and valleys in it.
c) As the magnetic chuck is used, it will have dents and scratches. Since the lamination is bolted to the body, the working life of the magnetic chuck is limited to the tapping depth of the bolting arrangement.

The prior art practices to remove the scratches or dents so formed is to mill or grind the working face to make it smooth again. The other problem with the prior art apparatus construction is that the provision of taps underneath the working face. Once the tapped holes are opened up, it will expose the magnetic chuck underneath and water or coolant can seep in.

To overcome the drawbacks of the prior art, there is a dire need to develop a solidly constructed Electro Permanent Magnetic (EPM) clamping apparatus that eliminates the seepage of coolant, or water through the working face.

Brief Summary of the invention

The following presents a simplified summary of the disclosure in order to provide a basic understanding to the reader. This summary is not an extensive overview of the disclosure, and it does not identify key elements of the invention or delineate the scope of the invention. Its sole purpose is to present some concepts disclosed herein in a simplified form as a prelude to the more detailed description that is presented later.

It is a prime object of the present invention to construct an Electro Permanent Magnetic (EPM) clamping apparatus for clamping of work pieces during machining operation/ grinding operation etcs.

It is yet another object of the invention to eliminate the seepage of coolant through the working face of clamping apparatus.

According to an aspect of the present invention, an Electro Permanent Magnetic (EPM) clamping apparatus for no seepage of coolant through its working face is disclosed. The EPM clamping apparatus comprises a top plate, coil, a bottom plate, and bolts.

In accordance with the aspect of the present invention, wherein the top plate is machined to have recess on the top face and on the rear face. The recess on the top face of the said top plate is filled with magnetic and non-magnetic fillings.

In accordance with the aspect of the present invention, the EPM clamping apparatus act as housing for the reversible magnets each wound up with a coil(s).

In accordance with the aspect of the present invention, wherein the top plate is having recess on both faces wherein, on the working face recess are provided and filled it up with magnetic fillings, in between non-magnetic material.

In accordance with the aspect of the present invention, the EPM clamping apparatus houses the electrical coil inside the top plate. A small shorting is left between the top and bottom recess such that fluids cannot seep inside the EPM apparatus.

In accordance with the aspect of the present invention, the EPM apparatus holds a workpiece on energizing the reversible magnets by a small pulse of electricity in a particular direction, say N or S orientation.

In accordance with the aspect of the present invention, wherein the non-magnetic materials filled into the recess are brass, aluminum, stainless steel or similar non-magnetic material.

In accordance with the aspect of the present invention, the apparatus releases the work piece when a pulsating alternating polarity of current is passed through the coil for a few seconds so that is demagnetizes the reversible magnet(s).

In particular, all combinations of claimed subject matter appearing at the end of this disclosure are contemplated as being part of the inventive subject matter disclosed herein. It should also be appreciated that terminology explicitly employed herein that also may appear in any disclosure incorporated by reference should be accorded a meaning most consistent with the particular concepts disclosed herein.

Brief Description of the Drawings

The invention will be further understood from the following detailed description of a preferred embodiment taken in conjunction with an appended drawing, in which:

Fig. 1a illustrates a prior art magnetic clamping apparatus for holding work pieces;

Fig. 1b illustrates a laminated top plate that is assembled on the top of the magnetic assemble illustrated in Fig. 1a;

Fig. 1c illustrates another prior art, a magnetic clamping apparatus for holding work pieces;

Fig. 2 illustrates an Electro Permanent Magnetic (EPM) clamping apparatus in accordance with a first exemplary embodiment of the present invention;

Fig. 3 illustrates one variation of placement of components of a clamping apparatus in accordance with a second exemplary embodiment of the present invention;

Fig. 4 illustrates another variation of placement of components of a clamping apparatus in accordance with a third exemplary embodiment of the present invention.

Fig. 5 illustrates another variation of placement of components of a clamping apparatus in accordance with a fourth exemplary embodiment of the present invention.

Fig. 6 illustrates another variation of placement of components of a clamping apparatus in accordance with a fifth exemplary embodiment of the present invention.

Detailed Description of the invention

It is to be understood that the present disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The present disclosure is capable of other embodiments and of being practiced or of being carried out in various ways. In addition, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

The use of “including”, “comprising” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced items. Further, the use of terms “first”, “second”, and “third”, and the like, herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another.

According to a first exemplary embodiment of the present invention, an Electro Permanent Magnetic (EPM) clamping apparatus for no seepage of coolant through its working face is disclosed. The EPM clamping apparatus comprises of a top plate, a coil, a bottom plate, and bolts.

In accordance with the first exemplary embodiment of the present invention, the top plate of the EPM clamping apparatus comprises recess on the working face and the bottom face. The recesses on the bottom face are filled with reversible magnets surrounded by a coil. The recess on the working face is filled with an array of non-magnetic and magnetic fillings. The recess is placed such that they are on either side of the reversible magnet.

In accordance with the first exemplary embodiment of the present invention, in between the recess of the working and bottom face, a small shorting of steel is left such that no liquid like water, or coolant etc., can pass through it.

In accordance with the first exemplary embodiment of the present invention, the placement of the recess is such that they optimize the magnetic area of the working face. Recesses are made on the top of reversible magnet making it suitable to clamp thin and thick jobs. The bottom plate is placed underneath to complete the magnetic circuit and seal the same.

In accordance with the first exemplary embodiment of the present invention, the apparatus holds a work piece on energizing the reversible magnets by a small pulse of electricity in a particular direction (say N, or S orientation). The apparatus releases the work piece when a pulsating diminishing reversing polarity is passed through the coil for a few seconds.

Referring to the Figures, Fig. 2 illustrates the EPM clamping apparatus in accordance with the first exemplary embodiment of the present invention. The apparatus comprises the top plate (2) machined to have slotted recess (14, 16) on rear and working faces leaving a steel piece as magnetic shorting. The top plate (2) is closed from bottom side using the bottom plate (10) by using bolts (12). The recess (16) on working face are filled with an array of magnet (4) and non-magnetic (8) fillings. The recess (14) on rear side of the top plate (2) acts as housing for the reversible magnets (4) surrounded by a coil (6).

The apparatus (1) as shown in Fig. 2 holds a work piece on energizing the reversible magnets (4) by a small pulse of electricity in a particular direction (say N, or S orientation). The apparatus (1) releases the work piece when a pulsating diminishing alternative polarity is passed through the coil (6) for a a few seconds.

The apparatus (1) as shown in Fig. 2 the top plate (2) which has slotted recess on working and bottom faces (16, 14) leaves a solid portion of steel in between them such that there is no seepage of coolant or other liquids through it.

Fig. 3 illustrates an alternative construction of the EPM clamping apparatus (1) in accordance with a second exemplary embodiment of the present invention. In this construction, the top plate (2) has recess on both faces namely working face and rear face. The rear face recess (14) is placed with reversible magnet (4) and coil (6). The working face recess (16) is filled with non-magnetic fillings (8) like brass/ aluminium/ stainless steel epoxy or similar. The bottom plate (10) is placed underneath to complete the circuit and seal the apparatus.

Fig. 4 illustrates an alternative construction of the EPM clamping apparatus (1) in accordance with a third exemplary embodiment of the present invention. In this construction, the top plate (2) has recess on both faces, working recess (16) is filled up with non-magnetic fillings (8) and bottom recess (14) is filled up with non-reversible magnet and also houses reversible magnets (4) and coil (6). The apparatus holds a work piece on energizing the reversible magnets (4) by a small pulse of electricity in a particular direction (say N, or S orientation). The apparatus (1) releases the work piece when current of reverse polarity is passed through the coil (6) for a split second.

Fig.5 illustrates an alternative construction of the EPM clamping apparatus (1) in accordance with a fourth exemplary embodiment of the present invention. In this construction, the bottom plate (10) is composed of recess having reversible magnets (4) and coil (6). The top plate (2) closing the bottom plate is machined recess on bottom face for filling the non-magnetic fillings (8) and the both plates are bolted.

Fig. 6 illustrates an alternative construction of the EPM clamping apparatus (1) in accordance with a fifth exemplary embodiment of the present invention. In this construction, the bottom plate (10) is composed of recess for placing the reversible magnets (4) and coils (6). The top plate (2) is machined top face as well as bottom face (10), the top recess (16) is filled with non-magnetic fillings (8) and bottom recess (14) is filled with non-reversible magnets (18).

,CLAIMS:5. CLAIMS
We Claim:
1. An Electro Permanent Magnetic (EPM) clamping apparatus (1), comprising:
a top plate (2), coil (6), a bottom plate (10), and bolts (12);
the said top plate (2) is machined to have slotted recess (14, 16) on rear and working faces;
the top plate (2) is closed from rear side using a bottom plate (10) by using bolts (12);
Characterized in that
the said recess (16) on working face are filled with reversible magnetic filling (4), in between a non-magnetic filling (8);
the said recess (14) on rear side of the top plate (2) act as housing for the reversible magnets (4) windup with said coil (6);
the said apparatus (1) holds a work piece on energizing the reversible magnets (4) by a small pulse of electricity in a particular direction (say N or S orientation);
the said apparatus (1) releases the work piece when a reversing pulsating diminishing polarity is passed through the coil (6) for a few seconds; and
wherein, the top plate (2) with slotted recess on working and rear faces (16, 14) has a steel shorting left between, allowing no seepage through it.

2. The apparatus (1) as claimed in claim 1, wherein the said non-magnetic filling (8) in the recess (16) on the working side of the said top plate (2) includes brass, aluminium, stainless steel, or epoxy or similar non-magnetic material.

3. The apparatus (1) as claimed in claim 1, the said recess (16) on working face filled with reversible magnetic filling (4) and non-magnetic filling (8) distributes the magnetic poles to leverage lower magnetic flux throw.

4. The apparatus (1) as claimed in claim 1, wherein the bottom plate (10) of the apparatus (1) completes the magnetic circuit and conceals the apparatus (1).

5. The apparatus (1) as claimed in claim 1, wherein the placement of the recess (14, 16) maximizes the magnetic area and minimizes the non-reversible area.

6. The apparatus (1) as claimed in claim 1, wherein the recess (as shown in Fig. 3) in the working part of the top plate (2) houses only non-magnetic filling (8) like brass, aluminum, stainless steel, epoxy resin or similar material.

7. The apparatus (1) as claimed in claim 1, wherein the rear side of the top plate (2) recess (as shown in Fig. 4) houses both non-reversible magnets and also reversible magnets (4) surrounded by coils (6).

8. The apparatus (1) as claimed in claim 1, wherein the bottom plate has recess (as shown in Fig.5) and it houses reversible magnets (4) and the said coil (6), wherein the top plate (2) has recesses on the working face that houses the non-magnetic filling(s) (8) to create magnetic poles.

9. The apparatus (1) as claimed in claim 1, wherein the bottom plate (10) (as shown in Fig.5) has small shorting left in the bottom side to make sure that water, or coolant does not seep inside the magnet (4).

10. The apparatus (1) as claimed in claim 1, wherein the rear side of the top plate (2) recess (as shown in Fig. 6) houses non-reversible magnets, and the bottom plate houses the reversible magnets (4) surrounded by coils (6).

6. DATE AND SIGNATURE

Dated this 15th day of June, 2022