ELECTROMAGNETIC VIBRATOR
United States Patent 3764834
An electromagnetic vibrator in the form of a dual mass vibratory system. The vibrator includes a first mass in the form of a base having a central recess and including at least two extensions extending substantially parallel to the vibration axis of the vibrator. A magnetic system is positioned within the recess. The vibrator includes further at least one leaf spring packet and rigid thread means associated with the extensions for fastening ends of the at least one leaf spring packet. Means are provided for rigidly coupling the central portion of the at least one leaf spring packet to a second mass.
US Patent References:
Electromagnetic vibrators
Spurlin - January 1965 - 3167670
Aluminum leaf spring spacer
Spurlin et al. - November 1964 - 3155853
Tuning of vibratory systems
Cerminara - November 1954 - 2694156
Electromagnetic vibrators
Spurlin - January 1965 - 3167670
Aluminum leaf spring spacer
Spurlin et al. - November 1964 - 3155853
Tuning of vibratory systems
Cerminara - November 1954 - 2694156
Inventors:
Brosch, Leo (Stetten, DT)
Fechner, Gerd (Goppingen, DT)
Reichert, Eduard (Kirchheim-Otlingen, DT)
Fechner, Gerd (Goppingen, DT)
Reichert, Eduard (Kirchheim-Otlingen, DT)
Application Number:
05/189233
Publication Date:
10/09/1973
Filing Date:
10/14/1971
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
310/29
International Classes:
H02K33/04; H02K33/00; H02K33/02
Field of Search:
310/15,17,29,28
Primary Examiner:
Duggan D. F.
Claims:
We claim
1. In an electromagnetic vibrator having a vibrating axis and constructed in the form of a dual mass vibratory system the improvement comprising in combination: a first mass in the form of a base having a central recess, said base including at least two stiff, rigid extensions extending substantially parallel to the vibration axis of the vibrator and having respective threaded bores therein; radially extending external ribs stiffening said extensions, resulting in a progressive spring rate; a magnetic system within said recess; at least one leaf spring packet composed of a plurality of individual springs and thin, relatively narrow, highly stressable intermediate layers having inwardly prepressed contacting edges, said layers being disposed between said springs; respective rigid threaded, high-tensile expansion screw bolts positioned in said respective bores of said extensions and extending through respective end portions of said at least one leaf spring packet for rigidly and securely fastening ends of said at least one leaf spring packet against tension forces; a second mass; and means for rigidly coupling said second mass to the central portion of said at least one leaf spring packet whereby the elastic resetting force for the realization of the vibrating movement is obtained by utilization of the superposition of the deflecting force on the pulling force due to the longitudinal expansion of the leaf springs forming the at least one leaf spring packet.
2. The apparatus as defined in claim 1 wherein the magnetic system comprises a C-shaped core.
3. The apparatus as defined in claim 1 wherein the magnetic system is fixed in said recess by cast resin means.
4. The apparatus as defined in claim 2 wherein the C-core is fixed in said recess by cast resin means.
5. The apparatus as defined in claim 1 including a U-shaped member embracing the at least one spring packet on the side thereof remote from the base.
6. The apparatus as defined in claim 1 including a protective hood means for enclosing active components, said hood means including stepped regions at which fastening bolts and annular eyes for transporting purposes are provided.
7. The apparatus as defined in claim 6 wherein the protective hood means is seated on outer edge portions of said base by means of a profiled seal and a recess formed in the outer edge portions of the base.
8. The apparatus as defined in claim 1 wherein the first mass is the working means of the vibrator.
1. In an electromagnetic vibrator having a vibrating axis and constructed in the form of a dual mass vibratory system the improvement comprising in combination: a first mass in the form of a base having a central recess, said base including at least two stiff, rigid extensions extending substantially parallel to the vibration axis of the vibrator and having respective threaded bores therein; radially extending external ribs stiffening said extensions, resulting in a progressive spring rate; a magnetic system within said recess; at least one leaf spring packet composed of a plurality of individual springs and thin, relatively narrow, highly stressable intermediate layers having inwardly prepressed contacting edges, said layers being disposed between said springs; respective rigid threaded, high-tensile expansion screw bolts positioned in said respective bores of said extensions and extending through respective end portions of said at least one leaf spring packet for rigidly and securely fastening ends of said at least one leaf spring packet against tension forces; a second mass; and means for rigidly coupling said second mass to the central portion of said at least one leaf spring packet whereby the elastic resetting force for the realization of the vibrating movement is obtained by utilization of the superposition of the deflecting force on the pulling force due to the longitudinal expansion of the leaf springs forming the at least one leaf spring packet.
2. The apparatus as defined in claim 1 wherein the magnetic system comprises a C-shaped core.
3. The apparatus as defined in claim 1 wherein the magnetic system is fixed in said recess by cast resin means.
4. The apparatus as defined in claim 2 wherein the C-core is fixed in said recess by cast resin means.
5. The apparatus as defined in claim 1 including a U-shaped member embracing the at least one spring packet on the side thereof remote from the base.
6. The apparatus as defined in claim 1 including a protective hood means for enclosing active components, said hood means including stepped regions at which fastening bolts and annular eyes for transporting purposes are provided.
7. The apparatus as defined in claim 6 wherein the protective hood means is seated on outer edge portions of said base by means of a profiled seal and a recess formed in the outer edge portions of the base.
8. The apparatus as defined in claim 1 wherein the first mass is the working means of the vibrator.
Description:
BACKGROUND OF THE INVENTION
This invention relates to an electromagnetic vibrator in the form of a dual mass vibratory system. In particular, the invention relates to an electromagnetic vibrator in the form of a dual mass vibratory system using leaf springs as spring elements.
It has already been proposed to clamp leaf spring packets which serve as the vibratory element in an electromagnetic vibrator, contrary to the previous custom, rigidly and particularly force-transmittingly in longitudinal direction so that when the springs are vibrating, their tensile strength is stressed more than their bending strength which constitutes a substantial increase in the magnitude of the resetting force.
This increased stress in the axial direction of the springs must, of course, also be absorbed by the fastening portions and the spring-supporting frame. Elasticity and/or resiliency in these portions of the vibrator lower the calculated spring constant which permits the development of undesirable natural frequencies and reduce the attainable useful output.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an electromagnetic vibrator in the form of a dual mass vibrator system having an improved, high useful output.
It is another object of the present invention to provide an electromagnetic vibrator in the form of a dual mass vibrator system in which a mass in the form of a base is provided with extensions which extend substantially parallel to the vibration axis of the vibrator and include rigid thread means for fastening ends of a leaf spring packet.
It is a further object of the present invention to provide an electromagnetic vibrator in the form of a dual mass vibrator system in which a magnetic system is positioned within a recess formed within one of the dual masses.
It is an additional object of the present invention to provide an electromagnetic vibrator in the form of a dual mass vibrator system which is substantially free of undesirable resonances.
It is yet another object of the present invention to provide an electromagnetic vibrator in the form of a dual mass vibrator system from which heat removal is substantially improved.
It is yet a further object of the present invention to provide an electromagnetic vibrator in the form of a dual mass system which is simple and inexpensive to fabricate.
The abovementioned and additional objects are accomplished by an electromagnetic vibrator in the form of a dual mass vibratory system including a first mass in the form of a base having a central recess, the base including at least two extensions extending substantially parallel to the vibratory axis of the vibrator. A magnetic system is positioned within the recess. The vibrator includes additionally a leaf spring packet and rigid thread means associated with the two extensions for fastening ends of the leaf spring packet. A second mass is rigidly coupled by conventional means to the central portion of the leaf spring packet.
The first mass is preferably the operating mass and is designed as a base, more or less in the form of a plate, having a central recess to hold the magnetic system. The extensions, which extend substantially parallel to the vibration axis of the vibrator, contain at least two rigid threads which serve to fasten the ends of a leaf spring packet. The central portion of the leaf spring packet is rigidly coupled with the second mass.
With this particular design of the base, a high rigidity is obtained so that leaf spring mounts attached to the two outer edges can be considered to be sufficiently rigid.
A further improvement is realized if, according to a further inventive idea, the magnetic system is designed as a C-core and mounted in the recess of the base. Particularly when this magnetic system is rigidly connected with the base by means of a cast resin and the recess is fully filled with a solid mass, extraordinary rigidity is obtained which can even be augmented further by reinforcing ribs leading to the extensions for fastening the leaf spring packet.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of an electromagnetic vibrator in the form of a dual mass vibratory system according to the present invention.
FIG. 2 is a sectional view of a second embodiment of an electromagnetic vibratory system according to the present invention which has a higher vibrating frequency than the embodiment illustrated in FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring in detail to FIG. 1, the electromagnetic vibrator includes a base 10, more or less in the form of a plate, which includes a first mass illustrated as a working mass in accordance with a preferred embodiment.
The base 10 is provided on the right and left with rigid cast extensions 11 which are stiffened by ribs 12. Each of the extensions 11 is provided with a threaded bore, generally designated by the numeral 13.
A recess 14 is provided in the base 10 for accommodating a magnetic system which comprises a C-shaped core 15 and a winding 16. As illustrated, the C-shaped core 15 and the winding 16 are encased in cast resin.
A leaf spring packet, including a plurality of leaf springs 17 separated from one another by specific, highly stressable intermediate layers 18, is fixed at its ends to the extensions 11 by high-tensile bolts 19 (expansion screws) which extend into the threaded bores 13. The intermediate layers 18 may desirably have inwardly prepressed contacting edges. The intermediate layers 18 may be of conventional material.
The central portion of the leaf spring packet including the leaf springs 17 and the intermediate layers 18, is connected by conventional means to a second mass 20 which is separated from the C-shaped core 15 by an air gap and acts as an armature.
Center clamping of the leaf spring packet including the leaf springs 17 and the intermediate layers 18 is effected by bolts 21 which extend through a free side member 22. If desired for frequency tuning additional weights, generally designated by the numeral 23, may be fixed to the side member 22 by bolts 24 which extend through a plate 25, the plate 25 forming part of the additional weights.
The base 10 is provided with an indent or groove 26 extending around a surface in its periphery. A protective hood 27 having a seal of profiled material 28 is positioned over the structure, the profiled material 28 being seated in the indent or groove 26. The protective hood is provided with step-like indentations 29 for seating annular screws 30 which are provided to hold the protective hood 27 in place. As illustrated, the annular screws 30 are provided with free ends 31 of O-shape which may be used for transportation purposes.
During vibration strong tensile forces are exerted on the outer spring mounts, which forces are absorbed by the force-transmitting clamping arrangement, rigid housing including the extensions 11, the high-tensile bolts 19 (expansion screws) and the specific, highly stressable intermediate layers 18. Movement within the mount of the leaf spring packet is virtually impossible so that wearing from friction and undesirable damping from these causes are for practical purposes eliminated.
The embodiment of the invention illustrated in FIG. 2 of the drawings is constructed and operates similarly to the embodiment of the invention shown in FIG. 1 of the drawings. The prime numerals used in FIG. 2 designate parts corresponding to parts designated by corresponding numerals used in FIG. 1 without a prime sign. Thus, it is not necessary to describe FIG. 2 of the drawing in detail.
The electromagnetic vibrator in the form of a dual mass system as illustrated in FIG. 2 is provided with an air gap between a C-core 15' and a second mass 20' which is somewhat less than the air gap between the C-core 15 and mass 20 shown in FIG. 1. Additionally, the leaf spring packet composed of a plurality of leaf springs 17' and intermediate layers 18' is not as thick as the corresponding leaf spring packet shown in FIG. 1. As a consequence of these differences (smaller air gap and less total spring tension), the electromagnetic vibrator shown in FIG. 2 operates at a higher frequency (50 Hz) than the frequency (25 Hz) at which the vibrator shown in FIG. 1 operates.
While no additional weights, corresponding to weights 23, are illustrated in FIG. 2 of the drawing, it is to be appreciated that such weights could be placed between the plate 25' and the side member 22' if desired for frequency tuning.
With the configuration of the vibrator according to the present invention not only the desired rigidity is obtained for the clamping points of the leaf springs but also a simplification and reduction of cost of the fabrication is effected. In addition, due to the close position and connection of the magnetic system with the part in the operating side of the electromagnetic vibrator which serves as the base, the heat removal is substantially improved since the entire vibrator operating side acts as a reflecting surface, on the one hand, and, on the other hand, heat can be conducted via the vibrator mounting feet to a connecting block of the conveyor trough or the like. This permits substantially better utilization of the active material.
It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.
This invention relates to an electromagnetic vibrator in the form of a dual mass vibratory system. In particular, the invention relates to an electromagnetic vibrator in the form of a dual mass vibratory system using leaf springs as spring elements.
It has already been proposed to clamp leaf spring packets which serve as the vibratory element in an electromagnetic vibrator, contrary to the previous custom, rigidly and particularly force-transmittingly in longitudinal direction so that when the springs are vibrating, their tensile strength is stressed more than their bending strength which constitutes a substantial increase in the magnitude of the resetting force.
This increased stress in the axial direction of the springs must, of course, also be absorbed by the fastening portions and the spring-supporting frame. Elasticity and/or resiliency in these portions of the vibrator lower the calculated spring constant which permits the development of undesirable natural frequencies and reduce the attainable useful output.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an electromagnetic vibrator in the form of a dual mass vibrator system having an improved, high useful output.
It is another object of the present invention to provide an electromagnetic vibrator in the form of a dual mass vibrator system in which a mass in the form of a base is provided with extensions which extend substantially parallel to the vibration axis of the vibrator and include rigid thread means for fastening ends of a leaf spring packet.
It is a further object of the present invention to provide an electromagnetic vibrator in the form of a dual mass vibrator system in which a magnetic system is positioned within a recess formed within one of the dual masses.
It is an additional object of the present invention to provide an electromagnetic vibrator in the form of a dual mass vibrator system which is substantially free of undesirable resonances.
It is yet another object of the present invention to provide an electromagnetic vibrator in the form of a dual mass vibrator system from which heat removal is substantially improved.
It is yet a further object of the present invention to provide an electromagnetic vibrator in the form of a dual mass system which is simple and inexpensive to fabricate.
The abovementioned and additional objects are accomplished by an electromagnetic vibrator in the form of a dual mass vibratory system including a first mass in the form of a base having a central recess, the base including at least two extensions extending substantially parallel to the vibratory axis of the vibrator. A magnetic system is positioned within the recess. The vibrator includes additionally a leaf spring packet and rigid thread means associated with the two extensions for fastening ends of the leaf spring packet. A second mass is rigidly coupled by conventional means to the central portion of the leaf spring packet.
The first mass is preferably the operating mass and is designed as a base, more or less in the form of a plate, having a central recess to hold the magnetic system. The extensions, which extend substantially parallel to the vibration axis of the vibrator, contain at least two rigid threads which serve to fasten the ends of a leaf spring packet. The central portion of the leaf spring packet is rigidly coupled with the second mass.
With this particular design of the base, a high rigidity is obtained so that leaf spring mounts attached to the two outer edges can be considered to be sufficiently rigid.
A further improvement is realized if, according to a further inventive idea, the magnetic system is designed as a C-core and mounted in the recess of the base. Particularly when this magnetic system is rigidly connected with the base by means of a cast resin and the recess is fully filled with a solid mass, extraordinary rigidity is obtained which can even be augmented further by reinforcing ribs leading to the extensions for fastening the leaf spring packet.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of an electromagnetic vibrator in the form of a dual mass vibratory system according to the present invention.
FIG. 2 is a sectional view of a second embodiment of an electromagnetic vibratory system according to the present invention which has a higher vibrating frequency than the embodiment illustrated in FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring in detail to FIG. 1, the electromagnetic vibrator includes a base 10, more or less in the form of a plate, which includes a first mass illustrated as a working mass in accordance with a preferred embodiment.
The base 10 is provided on the right and left with rigid cast extensions 11 which are stiffened by ribs 12. Each of the extensions 11 is provided with a threaded bore, generally designated by the numeral 13.
A recess 14 is provided in the base 10 for accommodating a magnetic system which comprises a C-shaped core 15 and a winding 16. As illustrated, the C-shaped core 15 and the winding 16 are encased in cast resin.
A leaf spring packet, including a plurality of leaf springs 17 separated from one another by specific, highly stressable intermediate layers 18, is fixed at its ends to the extensions 11 by high-tensile bolts 19 (expansion screws) which extend into the threaded bores 13. The intermediate layers 18 may desirably have inwardly prepressed contacting edges. The intermediate layers 18 may be of conventional material.
The central portion of the leaf spring packet including the leaf springs 17 and the intermediate layers 18, is connected by conventional means to a second mass 20 which is separated from the C-shaped core 15 by an air gap and acts as an armature.
Center clamping of the leaf spring packet including the leaf springs 17 and the intermediate layers 18 is effected by bolts 21 which extend through a free side member 22. If desired for frequency tuning additional weights, generally designated by the numeral 23, may be fixed to the side member 22 by bolts 24 which extend through a plate 25, the plate 25 forming part of the additional weights.
The base 10 is provided with an indent or groove 26 extending around a surface in its periphery. A protective hood 27 having a seal of profiled material 28 is positioned over the structure, the profiled material 28 being seated in the indent or groove 26. The protective hood is provided with step-like indentations 29 for seating annular screws 30 which are provided to hold the protective hood 27 in place. As illustrated, the annular screws 30 are provided with free ends 31 of O-shape which may be used for transportation purposes.
During vibration strong tensile forces are exerted on the outer spring mounts, which forces are absorbed by the force-transmitting clamping arrangement, rigid housing including the extensions 11, the high-tensile bolts 19 (expansion screws) and the specific, highly stressable intermediate layers 18. Movement within the mount of the leaf spring packet is virtually impossible so that wearing from friction and undesirable damping from these causes are for practical purposes eliminated.
The embodiment of the invention illustrated in FIG. 2 of the drawings is constructed and operates similarly to the embodiment of the invention shown in FIG. 1 of the drawings. The prime numerals used in FIG. 2 designate parts corresponding to parts designated by corresponding numerals used in FIG. 1 without a prime sign. Thus, it is not necessary to describe FIG. 2 of the drawing in detail.
The electromagnetic vibrator in the form of a dual mass system as illustrated in FIG. 2 is provided with an air gap between a C-core 15' and a second mass 20' which is somewhat less than the air gap between the C-core 15 and mass 20 shown in FIG. 1. Additionally, the leaf spring packet composed of a plurality of leaf springs 17' and intermediate layers 18' is not as thick as the corresponding leaf spring packet shown in FIG. 1. As a consequence of these differences (smaller air gap and less total spring tension), the electromagnetic vibrator shown in FIG. 2 operates at a higher frequency (50 Hz) than the frequency (25 Hz) at which the vibrator shown in FIG. 1 operates.
While no additional weights, corresponding to weights 23, are illustrated in FIG. 2 of the drawing, it is to be appreciated that such weights could be placed between the plate 25' and the side member 22' if desired for frequency tuning.
With the configuration of the vibrator according to the present invention not only the desired rigidity is obtained for the clamping points of the leaf springs but also a simplification and reduction of cost of the fabrication is effected. In addition, due to the close position and connection of the magnetic system with the part in the operating side of the electromagnetic vibrator which serves as the base, the heat removal is substantially improved since the entire vibrator operating side acts as a reflecting surface, on the one hand, and, on the other hand, heat can be conducted via the vibrator mounting feet to a connecting block of the conveyor trough or the like. This permits substantially better utilization of the active material.
It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.