阅读说明：本技术 一种用于钢梁初加工用端面锯床 (End face sawing machine for steel beam preliminary machining ) 是由 徐瑞宏 于 2021-11-11 设计创作，主要内容包括：本发明涉及钢梁加工设备技术领域,且公开了一种用于钢梁初加工用端面锯床,所述切割床的中心开设有切割槽,切割槽的内部设置有锯片,切割床的内部设置有输送机构,通过固定机构以及加设的橡胶垫层与垫片不仅可以起到降低钢梁与固定机构之间的磨损,还可以增加钢梁与固定机构之间的摩擦力,从而提高固定机构对钢梁的固定能力,避免了因钢梁在切割时与锯片接触受到巨大的摩擦产生严重的抖动,使得钢梁固定不稳定而出现的切割歪斜以及可能导致钢梁报废的问题,通过设置的输送机构防止了钢梁输送时出现跑偏现象,并且避免了由于钢梁质量大,使得钢梁调整起来费时费力,而且还降低了钢梁的切割效率的问题。(The invention relates to the technical field of steel beam processing equipment, and discloses an end face sawing machine for steel beam primary processing, wherein a cutting groove is formed in the center of the cutting machine, a saw blade is arranged inside the cutting groove, a conveying mechanism is arranged inside the cutting machine, the fixing mechanism, a rubber cushion layer and a gasket are additionally arranged, so that the abrasion between a steel beam and the fixing mechanism can be reduced, the friction between the steel beam and the fixing mechanism can be increased, the fixing capability of the fixing mechanism on the steel beam is improved, the problems of cutting deflection and possible steel beam scrap caused by unstable steel beam fixing due to the fact that the steel beam is contacted with the saw blade to generate serious shaking during cutting are avoided, the deviation phenomenon during steel beam conveying is prevented through the arranged conveying mechanism, and time and labor are avoided due to large mass of the steel beam, but also reduces the problem of the cutting efficiency of the steel beam.)

1. The utility model provides a be used for girder steel for preliminary working terminal surface sawing machine, includes cutting bed (1) and fixed establishment, its characterized in that: cutting groove (2) have been seted up at the center of cutting bed (1), the inside of cutting groove (2) is provided with saw bit (3), the axle center of saw bit (3) and the terminal fixed connection of the rotor of first driving motor (4) and the top of saw bit (3) extend to outside the top of cutting bed (1), the inside of cutting bed (1) is provided with conveying mechanism.

The fixing mechanism comprises a first round rod (12), a second round rod (13), a first positioning plate (14), a second positioning plate (15), a first screw (16) and a second screw (17), a top plate (18) is arranged at the tops of the first round rod (12) and the second round rod (13), the bottoms of the first round rod (12) and the second round rod (13) are fixedly connected with the top of the threaded sleeve (11), the first screw (16) is arranged at the left side of the first positioning plate (14), the first screw (16) penetrates through the first positioning plate (14) and is fixedly connected with a first contact disc (19), the second screw (17) is arranged at the right side of the second positioning plate (15), the second screw (17) penetrates through the second positioning plate (15) and is fixedly connected with a second contact disc (20), a first rotating rod (21) is arranged at the left end of the first screw (16), the right-hand member of second screw rod (17) is provided with second bull stick (22), the outside of cutting bed (1) is provided with controller and external power source, all link to each other with controller and external power source electrical property between first driving motor (4), second driving motor (7) and air exhauster (24).

2. The end face sawing machine for steel beam primary processing according to claim 1, wherein: conveying mechanism includes first threaded rod (5) and second threaded rod (6), the terminal fixed connection of rotor of the one end of first threaded rod (5) and second driving motor (7), first runner (8) and second runner (9) of fixedly connected with are established and overlap respectively in the upper portion outside of first threaded rod (5) and second threaded rod (6), it is equipped with driving belt (10) to add between first runner (8) and second runner (9), the outside of first threaded rod (5) and second threaded rod (6) all is overlapped and is equipped with thread bush (11), the top fixed mounting of thread bush (11) has fixed establishment.

3. The end face sawing machine for steel beam primary processing according to claim 1, wherein: the bottom of cutting groove (2) is provided with discharge passage (23), the bin outlet fixed mounting of discharge passage (23) has the diameter size of air exhauster (24) and the internal diameter size phase-match of discharge passage (23), discharge passage (23) are linked together through ejection of compact pipeline (25) and outside collecting box.

4. The face sawing machine for steel beam preliminary working according to claim 2, wherein: spout (26) have all been seted up to the left and right sides of cutting bed (1), the one end that first driving motor (4) were kept away from in spout (26) is all rotated through bearing (27) at first threaded rod (5) and the both ends of second threaded rod (6) and is connected in spout (26), the outside threaded connection of inner wall and first threaded rod (5) and second threaded rod (6) of through-hole and through-hole is seted up in thread bush (11), the top of both sides inner wall sliding connection and thread bush (11) of both sides and spout (26) of thread bush (11) extends to outside the top of cutting bed (1).

5. The end face sawing machine for steel beam primary processing according to claim 1, wherein: the quantity of first pole (12) and second pole (13) is two sets of and the upper portion of first pole (12) and second pole (13) all is provided with the screw thread, the right side annular face of first pole (12) and the left side fixed weld of first locating plate (14), the left side annular face of second pole (13) and the right side fixed weld of second locating plate (15).

6. The end face sawing machine for steel beam primary processing according to claim 1, wherein: screw hole (28) have been seted up at roof (18) top corresponding first round bar (12) and second round bar (13), screw hole (28) are all run through and first nut (29) and second nut (30) fixed connection are passed through to the top of first round bar (12) and second round bar (13).

7. The end face sawing machine for steel beam primary processing according to claim 1, wherein: the number of the first screw rods (16), the first contact discs (19), the first rotating rods (21), the second screw rods (17), the second contact discs (20) and the second rotating rods (22) is two, two sets of through holes are formed in the first positioning plate (14) and the second positioning plate (15), and the outer portions of the first screw rods (16) and the second screw rods (17) are connected with the inner wall threads of the through holes.

8. The end face sawing machine for steel beam primary processing according to claim 1, wherein: the opposite surfaces of the first contact disc (19) and the second contact disc (20) are respectively provided with a rubber cushion layer (31), and the top of the threaded sleeve (11) is provided with a gasket (32).

9. The end face sawing machine for steel beam primary processing according to claim 1, wherein: first bull stick (21) and first screw rod (16) and second bull stick (22) and second screw rod (17) are the integral type structure, the outside of first bull stick (21) and second bull stick (22) all is provided with skid resistant course (33).

Technical Field

The invention relates to the technical field of steel beam processing equipment, in particular to an end face sawing machine for steel beam primary processing.

Background

The steel beam is a long steel bar, and is also called as an I-steel because the section of the steel beam is I-shaped, so the steel beam is widely applied to crane beams and working platform beams in factory buildings, floor beams in multi-storey buildings, purlins in roof structures and the like.

The existing steel beam sawing machine usually adopts a telescopic cylinder to push a clamping plate to simply fix the steel beam when cutting the steel beam, but because the friction force parallel to a saw blade is generated in the steel beam cutting process, the steel beam is contacted with the saw blade to generate great friction and generate serious shaking when cutting, the steel beam is unstable to fix and is possibly cut to be inclined, even the steel beam is scrapped, unnecessary loss is generated, and the existing steel beam sawing machine moves the steel beam to a cutting notch through a conveying roller to cut, the steel beam is possibly displaced up and down in the conveying process to deflect, because the steel beam cannot be ensured to be always in a state vertical to the saw blade in the conveying process, a knife edge can be deflected in the subsequent cutting operation, the position of the steel beam needs to be adjusted and fixed, and because the steel beam has large mass, the adjustment is got up and is wasted time and energy, has not only increased the unnecessary work load of operation personnel, but also has reduced the cutting efficiency of girder steel, for this reason we provide one kind and are used for girder steel for the preliminary working end face sawing machine.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides an end face sawing machine for steel beam primary processing, which aims to solve the problems in the background art.

(II) technical scheme

In order to achieve the purpose, the invention provides the following technical scheme: the utility model provides a be used for girder steel for preliminary working terminal surface sawing machine, includes the cutting bed, cut groove has been seted up at the center of cutting bed, cut groove's inside and be provided with the saw bit, outside the axle center of saw bit extended to the top of cutting bed with the terminal fixed connection of first driving motor's rotor and the top of saw bit, the inside of cutting bed is provided with conveying mechanism.

The fixing mechanism comprises a first round rod, a second round rod, a first positioning plate, a second positioning plate, a first screw rod and a second screw rod, the top parts of the first round rod and the second round rod are provided with top plates, the bottom parts of the first round rod and the second round rod are fixedly connected with the top part of the threaded sleeve, the first screw rod is arranged at the left side of the first positioning plate and penetrates through the first positioning plate and is fixedly connected with a first contact disc, the second screw rod is arranged at the right side of the second positioning plate and penetrates through the second positioning plate and is fixedly connected with a second contact disc, the left end of the first screw rod is provided with a first rotating rod, the right end of the second screw rod is provided with a second rotating rod, the cutting bed is characterized in that a controller and an external power supply are arranged outside the cutting bed, and the first driving motor, the second driving motor and the exhaust fan are electrically connected with the controller and the external power supply.

Preferably, conveying mechanism includes first threaded rod and second threaded rod, the one end of first threaded rod and second driving motor's the terminal fixed connection of rotor, the upper portion outside of first threaded rod and second threaded rod is overlapped respectively and is established and first runner of fixedly connected with and second runner, it is equipped with driving belt to add between first runner and the second runner, the outside of first threaded rod and second threaded rod all is overlapped and is equipped with the thread bush, the top fixed mounting of thread bush has fixed establishment.

Preferably, the bottom of cutting the groove is provided with discharge passage, discharge opening fixed mounting of discharge passage has the diameter size of air exhauster and discharge passage's internal diameter size phase-match, discharge passage is linked together through ejection of compact pipeline and outside collecting box.

Preferably, the spout has all been seted up to the left and right sides of cutting bed, the one end that first driving motor was kept away from to first threaded rod all rotates through the bearing with the both ends of second threaded rod and connects in the spout, the threaded sleeve sets up the inner wall of through-hole and the outside threaded connection of first threaded rod and second threaded rod, the both sides of threaded sleeve and the both sides inner wall sliding connection of spout and the top of threaded sleeve extend to outside the top of cutting bed.

Preferably, the quantity of first round bar and second round bar is two sets of and the upper portion of first round bar and second round bar all is provided with the screw thread, the right side annular face of first round bar and the left side fixed weld of first locating plate, the left side annular face of second round bar and the right side fixed weld of second locating plate.

Preferably, the top plate is provided with a screw hole corresponding to the tops of the first round rod and the second round rod, and the tops of the first round rod and the second round rod penetrate through the screw hole and are fixedly connected with the second nut through the first nut.

Preferably, the number of the first screw, the first contact disc, the first rotating rod, the second screw, the second contact disc and the second rotating rod is two, two sets of through holes are formed in the first positioning plate and the second positioning plate, and the outer portions of the first screw and the second screw are in threaded connection with the inner walls of the through holes.

Preferably, the opposite surfaces of the first contact disc and the second contact disc are respectively provided with a rubber cushion layer, and the top of the threaded sleeve is provided with a gasket.

Preferably, the first rotating rod and the first screw rod are of an integrated structure with the second rotating rod and the second screw rod, and anti-slip layers are arranged outside the first rotating rod and the second rotating rod.

(III) advantageous effects

Compared with the prior art, the invention provides an end face sawing machine for steel beam primary processing, which has the following beneficial effects:

1. the end face sawing machine for steel beam primary processing is characterized in that a steel beam is arranged between a top plate and a threaded sleeve, the tops of a first round rod and a second round rod penetrate through screw holes formed in the top plate, the top plate is tightly abutted to the upper surface of the steel beam, then the fixing effect on the steel beam is increased through fixedly connecting a first nut and a second nut, the first rotating rod and the second rotating rod are rotated, a first contact disc and a second contact disc are both drawn close to the steel beam and tightly abutted to the side surface of the steel beam by utilizing a first screw rod and a second screw rod to achieve the effect of jointly clamping and fixing the steel beam, two groups of gaskets are arranged on the first rotating rod, the first screw rod, the first contact disc, the second rotating rod, the second screw rod and the second contact disc, the effect of jointly clamping and fixing the steel beam is further improved, and rubber gaskets additionally arranged on the top of the threaded sleeve and the opposite surfaces of the first contact disc and the second contact disc are additionally arranged, not only can play the wearing and tearing that reduce between girder steel and the fixed establishment, can also increase the frictional force between girder steel and the fixed establishment to improve the fixed ability of fixed establishment to the girder steel, avoided receiving huge friction when the cutting and the saw bit contact because of the girder steel and produced serious shake, make the fixed unstable cutting that appears of girder steel crooked and probably lead to the condemned problem of girder steel.

2. This a be used for terminal surface sawing machine for girder steel preliminary working, fix the top at the thread bush through the both ends of fixed establishment with the girder steel, rotate through second driving motor and drive first threaded rod and rotate, and drive the second threaded rod simultaneously through driving belt, make the girder steel can at the uniform velocity and move towards the direction perpendicular and cut groove all the time and can not appear the off tracking because of the girder steel displacement from top to bottom in transportation process, can not cause edge of a knife off normal when having guaranteed to the girder steel cutting, cutting quality has been improved, the problem of wasting time and energy has been avoided simultaneously because the girder steel quality leads to the girder steel adjustment to get up greatly, and operating personnel unnecessary work load has been reduced, and the cutting efficiency of girder steel has still been improved.

Drawings

FIG. 1 is a schematic top view of the present invention;

FIG. 2 is a schematic cross-sectional view of the present invention;

FIG. 3 is a schematic view of a scrap collecting structure of the cutting groove of the present invention;

FIG. 4 is a front view of the fixing mechanism of the present invention;

FIG. 5 is a schematic top view of the fixing mechanism of the present invention;

FIG. 6 is a schematic top view of the top plate of the present invention;

in the figure: 1. cutting the bed; 2. cutting the groove; 3. a saw blade; 4. a first drive motor; 5. a first threaded rod; 6. a second threaded rod; 7. a second drive motor; 8. a first runner; 9. a second runner; 10. a drive belt; 11. a threaded sleeve; 12. a first round bar; 13. a second round bar; 14. a first positioning plate; 15. a second positioning plate; 16. a first screw; 17. a second screw; 18. a top plate; 19. a first contact pad; 20. a second contact pad; 21. a first rotating lever; 22. a second rotating rod; 23. a discharge channel; 24. an exhaust fan; 25. a discharge pipeline; 26. a chute; 27. a bearing; 28. a screw hole; 29. a first nut; 30. a second nut; 31. a rubber cushion layer; 32. a gasket; 33. and an anti-slip layer.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1, 2 and 3, the invention provides a technical scheme, in particular to an end face sawing machine for steel beam primary processing, which comprises a cutting bed 1, wherein a cutting groove 2 is formed in the center of the cutting bed 1, a saw blade 3 is arranged in the cutting groove 2, the axis of the saw blade 3 is fixedly connected with the tail end of a rotor of a first driving motor 4, the top of the saw blade 3 extends out of the top of the cutting bed 1, a discharge passage 23 is arranged at the bottom of the cutting groove 2, an exhaust fan 24 is fixedly arranged at a discharge port of the discharge passage 23, the diameter of the exhaust fan 24 is matched with the inner diameter of the discharge passage 23, the discharge passage 23 is communicated with an external collecting box through a discharge pipe 25, scraps generated in cutting operation fall into the cutting groove 2, metal scraps generated in cutting operation have a certain utilization value, and are adsorbed by the exhaust fan 24 at the discharge port of the discharge passage 23, the sweeps passes through discharge tube 25 and gets into in the outside collection box with higher speed, make the metal sweeps obtain the collection, be convenient for subsequent recovery and recycle, simultaneously still avoided piling up the problem that influences the cutting of saw bit 3 to the girder steel and cause saw bit 3 to damage in cutting cut 2 because of the sweeps for a long time, the inside of cutting bed 1 is provided with conveying mechanism, conveying mechanism includes first threaded rod 5 and second threaded rod 6, the terminal fixed connection of the one end of first threaded rod 5 and the rotor of second driving motor 7, overlap respectively and establish and fixedly connected with first runner 8 and second runner 9 in the upper portion outside of first threaded rod 5 and second threaded rod 6, it is equipped with driving belt 10 to add between first runner 8 and the second runner 9, the outside of first threaded rod 5 and second threaded rod 6 all is overlapped and is equipped with thread bush 11, spout 26 has all been seted up to the left and right sides of cutting bed 1, the one end that first driving motor 4 was kept away from to first threaded rod 5 and the both ends of second threaded rod 6 all rotate through bearing 27 The steel beam cutting machine is connected in the sliding groove 26, the threaded sleeve 11 is provided with a through hole, the inner wall of the through hole is in threaded connection with the outer parts of the first threaded rod 5 and the second threaded rod 6, the two sides of the threaded sleeve 11 are in sliding connection with the inner walls of the two sides of the sliding groove 26, the top of the threaded sleeve 11 extends out of the top of the cutting bed 1, the top of the threaded sleeve 11 is fixedly provided with a fixing mechanism, the two ends of the steel beam are fixed on the top of the threaded sleeve 11 through the fixing mechanism, the first threaded rod 5 is driven to rotate through the rotation of the second driving motor 7, the second threaded rod 6 is driven through the transmission belt 10, the steel beam can move at a constant speed and always towards the direction vertical to the cutting groove 2, the steel beam cannot deviate due to the vertical displacement of the steel beam in the conveying process, the deviation of the steel beam cannot be caused when the steel beam is cut, the cutting quality is improved, and the time and labor are avoided due to the large mass of the steel beam, not only increased the unnecessary work load of operation personnel, but also reduced the problem of the cutting efficiency of girder steel, the outside of cutting bed 1 is provided with controller and external power source, all links to each other with controller and external power source electrical property between first driving motor 4, second driving motor 7 and the air exhauster 24.

As shown in fig. 4, 5 and 6, the fixing mechanism includes a first round bar 12, a second round bar 13, a first positioning plate 14, a second positioning plate 15, a first screw 16 and a second screw 17, a top plate 18 is disposed on the top of the first round bar 12 and the second round bar 13, a screw hole 28 is disposed on the top plate 18 corresponding to the top of the first round bar 12 and the second round bar 13, the top of the first round bar 12 and the top of the second round bar 13 both penetrate through the screw hole 28 and are fixedly connected with a second nut 30 through the first nut 29, the top plate 18 is fixed on the top of the steel beam through the double-layer fixed connection of the first nut 29 and the second nut 30, so as to improve the stability of the steel beam, the bottom of the first round bar 12 and the bottom of the second round bar 13 are both fixedly connected with the top of the thread bushing 11, the number of the first round bar 12 and the number of the second round bar 13 are two groups, and the upper portions of the first round bar 12 and the second round bar 13 are both provided with threads, the right annular surface of the first round rod 12 is fixedly welded with the left side of the first positioning plate 14, the left annular surface of the second round rod 13 is fixedly welded with the right side of the second positioning plate 15, the first screw 16 is arranged on the left side of the first positioning plate 14, the first screw 16 penetrates through the first positioning plate 14 and is fixedly connected with a first contact disc 19, the second screw 17 is arranged on the right side of the second positioning plate 15, the second screw 17 penetrates through the second positioning plate 15 and is fixedly connected with a second contact disc 20, the left end of the first screw 16 is provided with a first rotating rod 21, the right end of the second screw 17 is provided with a second rotating rod 22, the first screw 16, the first contact disc 19, the first rotating rod 21, the second screw 17, the second contact disc 20 and the second rotating rod 22 are respectively in two groups, the first positioning plate 14 and the second positioning plate 15 are respectively provided with two groups of through holes, the outer parts of the first screw 16 and the second screw 17 are respectively in threaded connection with the inner walls of the through holes, the first rotating rod 21 and the second rotating rod 22 are rotated, the first screw rod 16 and the second screw rod 17 are utilized to enable the first contact disc 19 and the second contact disc 20 to be close to the steel beam and tightly abut against the side face of the steel beam to achieve the effect of clamping and fixing the steel beam together, two groups of the first rotating rod 21, the first screw rod 16, the first contact disc 19, the second rotating rod 22, the second screw rod 17 and the second contact disc 20 are arranged, the effect of clamping and fixing the steel beam together is further improved, rubber cushion layers 31 are additionally arranged on the opposite faces of the first contact disc 19 and the second contact disc 20, a gasket 32 is arranged at the top of the thread sleeve 11, and the gasket 32 and the rubber cushion layers 31 are additionally arranged, so that the abrasion between the steel beam and the fixing mechanism can be reduced, the friction force between the steel beam and the fixing mechanism can be increased, the fixing capacity of the fixing mechanism on the steel beam is improved, and the serious vibration caused by the huge friction when the steel beam is contacted with the 3 during cutting is avoided, make the fixed unstable cutting that appears of girder steel crooked and probably lead to the condemned problem of girder steel, first bull stick 21 and first screw rod 16 and second bull stick 22 and second screw rod 17 are the integral type structure, and the outside of first bull stick 21 and second bull stick 22 all is provided with skid resistant course 33, can play the frictional force between increase palm and the bull stick, and the better power of giving an effect of being convenient for rotates the bull stick.

The working principle of the device is as follows: firstly, two ends of the steel beam are placed between the top plate 18 and the threaded sleeve 11, so that the tops of the first round rod 12 and the second round rod 13 penetrate through the threaded hole 28 formed in the top plate 18, the first round rod and the second round rod are fixed through the first nut 29 and the second nut 30, so that the first round rod and the second round rod are tightly connected and abutted against the top of the steel beam, then the first rotating rod 21 is rotated, the first contact disc 19 is drawn towards the steel beam through the first screw 16, the second contact disc 20 is drawn towards the steel beam through the second screw 17 by rotating the second rotating rod 22, the first contact disc 19 and the second contact disc 20 are tightly abutted against the side surface of the steel beam to achieve the effect of commonly clamping and fixing the steel beam, two groups are arranged through the first rotating rod 21, the first screw 16, the first contact disc 19, the second rotating rod 22, the second screw 17 and the second contact disc 20, the effect of commonly clamping and fixing the steel beam is further improved, and the added gasket 32 and the rubber cushion 31 can not only reduce the abrasion between the fixing mechanism, the friction force between the steel beam and the fixing mechanism can be increased, so that the fixing capacity of the fixing mechanism to the steel beam is improved, the problems that the steel beam is contacted with the saw blade 3 to generate serious shaking due to huge friction when the steel beam is cut, the steel beam is fixed unstably and the steel beam is possibly scrapped are solved, then the cutting bed 1 is connected with an external power supply, the first driving motor 4 and the second driving motor 7 are started through an external controller, the rotor of the first driving motor 4 rotates to drive the saw blade 3 to rotate at high speed, the rotor of the second driving motor 7 rotates to drive the first threaded rod 5 to rotate, the first threaded rod 5 rotates to drive the first runner 8 to rotate, the first runner 8 rotates to drive the second runner 9 to rotate through the transmission belt 10, the second runner 9 rotates to drive the second threaded rod 6 to rotate simultaneously, so that the threaded sleeve 11 moves on the first threaded rod 5 and the second threaded rod 6 simultaneously to convey the steel beam to the cutting groove 2, the two ends of the steel beam are fixed at the top of the thread sleeve 11 by using the fixing mechanism, the steel beam can move towards the direction vertical to the cutting groove 2 at a constant speed and all the time through the conveying mechanism, and the steel beam can not deviate due to vertical displacement in the conveying process, thereby ensuring that the knife edge can not deviate when the steel beam is cut, improving the cutting quality, simultaneously avoiding the problems that the steel beam is time-consuming and labor-consuming to adjust due to large quality of the steel beam, not only increasing the unnecessary workload of operators, but also reducing the cutting efficiency of the steel beam, when the saw blade 3 cuts the steel beam, the exhaust fan 24 is started, the generated scraps fall to the discharge channel 23 and enter an external collection box through the discharge pipeline 25 by the exhaust fan 24 to recycle the metal scraps, avoiding the waste of the metal scraps, after the steel beam is cut, and (3) closing the first driving motor 4 and the exhaust fan 24, removing the cut steel beam, and controlling the second driving motor 7 to reversely rotate through an external controller to reset the threaded sleeve 11.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.