阅读说明：本技术 一种新型预制舱电缆连接结构 (Novel prefabricated cabin cable connection structure ) 是由 王荣 任谦 葛其运 袁超 姜潞 于 2019-03-13 设计创作，主要内容包括：本发明涉及预制舱技术领域,且公开了一种新型预制舱电缆连接结构。该新型预制舱电缆连接结构,包括舱体,所述舱体的内部包括开关柜、垫板、限位槽、限位块、通孔、保温板、第一电缆板、第二电缆板、电缆孔、箱口和箱门,开关柜位于舱体的内部设置,开关柜的底部与垫板的上表面固定连接,限位槽位于垫板的上表面开设,限位槽的内壁与限位块的表面相互配合,通孔位于舱体的左侧底部开设。该新型预制舱电缆连接结构,电缆孔设计成与水平成倾斜度45角结构,利于操作,方便电缆进入,同时保温板是由聚氨酯保温材料制成,此材料保温防火性能好且重量轻,使该新型预制舱电缆连接结构具有隔热和防火功能,安全性较高。(The invention relates to the technical field of prefabricated cabins, and discloses a novel prefabricated cabin cable connecting structure. This novel prefabricated cabin cable junction structure, including the cabin body, the inside of the cabin body includes cubical switchboard, backing plate, spacing groove, stopper, through-hole, heated board, first cable board, second cable board, cable hole, case mouth and chamber door, and the cubical switchboard is located the inside setting of the cabin body, and the bottom of cubical switchboard is connected with the last fixed surface of backing plate, and the spacing groove is located the upper surface of backing plate and sets up, and the inner wall of spacing groove mutually supports with the surface of stopper, and the through-hole is located the left side bottom of the cabin body and sets up. This novel prefabricated cabin cable connection structure, cable hole design become with the level 45 angle structures of gradient, do benefit to the operation, make things convenient for the cable to get into, the heated board is made by polyurethane insulation material simultaneously, this material keeps warm fire behavior is good and light in weight, makes this novel prefabricated cabin cable connection structure have thermal-insulated and fire prevention function, and the security is higher.)

1. The utility model provides a novel prefabricated cabin cable junction structure, includes the cabin body (1), the inside of the cabin body (1) includes cubical switchboard (2), backing plate (3), spacing groove (4), stopper (5), through-hole (6), heated board (7), first cable board (8), second cable board (9), cable hole (10), case mouth (11) and chamber door (12), its characterized in that: cubical switchboard (2) are located the inside setting of the cabin body (1), the bottom of cubical switchboard (2) is connected with the last fixed surface of backing plate (3), spacing groove (4) are located the upper surface of backing plate (3) and are seted up, the inner wall of spacing groove (4) is mutually supported with the surface of stopper (5), through-hole (6) are located the left side bottom of the cabin body (1) and are seted up, the inner wall of through-hole (6) is connected with the fixed surface of heated board (7), heated board (7) the left and right sides respectively with the right side of first cable board (8) and the left side fixed connection of second cable board (9), the right side of first cable board (8) and the left side fixed connection of the cabin body (1), the left side of second cable board (9) and the inner wall left side fixed connection of the cabin body (1), cable hole (10) are located the left side of first cable board (8) respectively, The left side of the heat insulation plate (7) and the left side of the second cable plate (9) are arranged, the box opening (11) is arranged at the top of the left side of the cabin body (1), the surface of the box door (12) is matched with the inner wall of the box opening (11), and the left side of the box door (12) is hinged with the left side of the cabin body (1) through a hinge;

the bottom of the cabin body (1) comprises a base (13), a groove (14), a supporting plate (15), an electric push rod (16), a fixing block (17), a sliding hole (18), a fixing ring (19), a fixing hole (20), a partition plate (21), a grounding copper bar (22) and a control panel (23), wherein the groove (14) is formed in the upper surface of the base (13), the top of the inner wall of the groove (14) is fixedly connected with the surface of the supporting plate (15), the upper surface of the supporting plate (15) is fixedly connected with the bottom of the limiting block (5), the bottom of the electric push rod (16) is fixedly connected with the bottom of the inner wall of the groove (14), one side, far away from the center of the base (13), of the electric push rod (16) is fixedly connected with one side, close to the center of the base (13), of the fixing block (17), of the sliding hole (18) is formed in the, the surface of slide opening (18) and the surface sliding connection of fixed block (17), the surface of base (13) and the inner wall sliding connection of solid fixed ring (19), fixed hole (20) are located the left and right sides of solid fixed ring (19) and are seted up, the inner wall of fixed hole (20) and the surface sliding connection of fixed block (17), the inner wall top of solid fixed ring (19) and the surface bottom fixed connection of the cabin body (1), the upper and lower both sides of baffle (21) respectively with the inner wall bottom of recess (14) and the bottom fixed connection of backup pad (15), the inner wall of recess (14) and the bottom fixed connection of ground connection copper bar (22), the bottom of ground connection copper bar (22) runs through base (13) and extends to the bottom of base (13), ground connection copper bar (22) are connected with cubical switchboard (2) electricity, the front of the cabin body (1) and the back fixed connection of control panel (23), the control panel (23) is electrically connected with the switch cabinet (2) and the electric push rod (16) respectively.

2. The novel prefabricated cabin cable connection structure of claim 1, wherein: the right side of the cabin body (1) comprises a ventilation hole (24), a dust guard (25) and a rain shield (26), the right side of the cabin body (1) in the ventilation hole (24) is opened, the inner wall of the ventilation hole (24) is fixedly connected with the surface of the dust guard (25), and the right side of the cabin body (1) is fixedly connected with the left side of the rain shield (26).

3. The novel prefabricated cabin cable connection structure of claim 1, wherein: the inside of the cabin body (1) comprises a limit ring (27), the upper surface of the limit ring (27) is fixedly connected with the top of the inner wall of the cabin body (1), and the inner wall of the limit ring (27) is connected with the switch cabinet (2) in a sliding manner.

4. The novel prefabricated cabin cable connection structure of claim 1, wherein: the sum of the height of the switch cabinet (2) and the thickness of the backing plate (3) is equal to the large height of the inner wall of the cabin body (1).

5. The novel prefabricated cabin cable connection structure of claim 1, wherein: the surface of the fixed block (17) comprises a stop block (28), one side, far away from the center of the base (13), of the stop block (28) is fixedly connected with one side, close to the center of the base (13), of the fixed block (17), and the inner wall of the stop block (28) is sleeved with the surface of the electric push rod (16).

6. The novel prefabricated cabin cable connection structure of claim 1, wherein: the inside of the box door (12) comprises a handle groove (29), and the handle groove (29) is positioned on the left side of the box door (12) and is opened.

7. The novel prefabricated cabin cable connection structure of claim 1, wherein: the included angle between the cable hole (10) and the horizontal plane is forty-five degrees.

8. The novel prefabricated cabin cable connection structure of claim 3, wherein: the limiting ring (27) is internally provided with an air groove (30), and the air groove (30) is formed in the inner wall of the limiting ring (27).

9. The novel prefabricated cabin cable connection structure of claim 1, wherein: the number of the partition plates (21) is two, and the two partition plates (21) are symmetrically distributed by taking the grounding copper bar (22) as the center.

Technical Field

The invention relates to the technical field of prefabricated cabins, in particular to a novel prefabricated cabin cable connecting structure.

Background

High-voltage cables are generally connected from the bottom or the top of high-voltage distribution equipment, a high-voltage switch cabinet is arranged in a vehicle-mounted prefabricated cabin (a box-type substation), and when the prefabricated cabin is arranged on a movable semi-trailer, the prefabricated cabin can be used for temporary power supply, but the cable connection structure of the existing prefabricated cabin has a troublesome high-voltage cable plugging operation process and poor equipment safety.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a novel cable connection structure for a prefabricated cabin, which has the advantages of convenience in wire plugging, high safety and the like, and solves the problems of troublesome high-voltage cable plugging operation process and poor equipment safety of the conventional cable connection structure for the prefabricated cabin.

(II) technical scheme

In order to realize the purposes of convenient wire plugging and high safety, the invention provides the following technical scheme: the utility model provides a novel prefabricated cabin cable junction structure, includes the cabin body, the inside of the cabin body includes cubical switchboard, backing plate, spacing groove, stopper, through-hole, heated board, first cable board, second cable board, cable hole, case mouth and chamber door, the cubical switchboard is located the inside setting of the cabin body, the bottom of cubical switchboard is connected with the last fixed surface of backing plate, the spacing groove is located the upper surface of backing plate and sets up, the inner wall of spacing groove and the surface of stopper mutually support, the through-hole is located the left side bottom of the cabin body and sets up, the inner wall of through-hole is connected with the fixed surface of heated board, the heated board left and right sides respectively with the right side of first cable board and the left side fixed connection of second cable board, the right side of first cable board and the left side fixed connection of the cabin body, the left side of second cable board and the inner wall left side fixed connection of the cabin body, the cable hole is located the left side of first cable, The left side of heated board and the left side of second cable board are seted up, the left side top that the case mouth is located the cabin body is seted up, the surface of chamber door mutually supports with the inner wall of case mouth, the left side of chamber door and the left side of the cabin body are passed through the hinge and are articulated.

The bottom of the cabin body comprises a base, a groove, a supporting plate, an electric push rod, a fixed block, a sliding hole, a fixed ring, a fixed hole, a partition plate, a grounding copper bar and a control panel, wherein the groove is formed in the upper surface of the base, the top of the inner wall of the groove is fixedly connected with the surface of the supporting plate, the upper surface of the supporting plate is fixedly connected with the bottom of a limiting block, the bottom of the electric push rod is fixedly connected with the bottom of the inner wall of the groove, one side of the electric push rod, which is far away from the center of the base, is fixedly connected with one side of the fixed block, which is close to the center of the base, the sliding hole is formed in the left side and the right side of the inner wall of the groove, the surface of the sliding hole is slidably connected with the surface of the fixed block, the surface, the utility model discloses a switch cabinet, including solid fixed ring, baffle, ground copper bar, switch board, fixed ring's inner wall top and the surface bottom fixed connection of the cabin body, the upper and lower both sides of baffle respectively with the inner wall bottom of recess and the bottom fixed connection of backup pad, the inner wall of recess and ground copper bar's bottom fixed connection, the bottom of ground copper bar runs through the base and extends to the bottom of base, the ground copper bar is connected with the switch cabinet electricity, the front of the cabin body and control panel's back fixed connection, control panel is connected with switch cabinet and electric putter electricity respectively.

Preferably, the right side of the cabin body includes ventilation hole, dust guard and rain cover, the ventilation hole is located the right side of the cabin body and is seted up, the inner wall in ventilation hole and the fixed surface of dust guard are connected, the right side of the cabin body and the left side fixed connection of rain cover.

Preferably, the cabin body comprises a limiting ring inside, the upper surface of the limiting ring is fixedly connected with the top of the inner wall of the cabin body, and the inner wall of the limiting ring is connected with the surface of the switch cabinet in a sliding manner.

Preferably, the sum of the height of the switch cabinet and the thickness of the cushion plate is equal to the large height of the inner wall of the cabin.

Preferably, the surface of fixed block includes the dog, one side that the base center was kept away from to the dog is close to one side fixed connection at the base center with the fixed block, the inner wall and the surface cup joint of electric putter of dog.

Preferably, the inside of the box door comprises a handle groove, and the handle groove is positioned on the left side of the box door.

Preferably, the angle between the cable hole and the horizontal plane is forty-five degrees.

Preferably, the limiting ring internally comprises an air groove, and the air groove is formed in the inner wall of the limiting ring.

Preferably, the number of the partition plates is two, and the two partition plates are symmetrically distributed by taking the grounding copper bar as the center.

Compared with the prior art, the invention provides a novel cable connection structure of a prefabricated cabin, which has the following beneficial effects:

1. the novel prefabricated cabin cable connection structure is beneficial to operation and convenient for cable entry by arranging the through hole, the insulation board, the first cable board, the second cable board and the cable hole, the cable hole is designed to form an inclined 45-degree structure with the horizontal plane, the insulation board is made of a polyurethane insulation material, the material has good heat insulation and fire resistance performance and light weight, the novel prefabricated cabin cable connection structure has heat insulation and fire resistance functions and higher safety, the first cable board and the second cable board are adopted at the cable hole, the double-layer steel plate structure is high in strength and good in heat insulation effect, the novel prefabricated cabin cable connection structure is suitable for most of domestic terrains and climatic conditions, the application range is wide, in addition, the base, the groove, the supporting board, the partition board and the grounding copper bar are arranged in an end-to-end connection mode to form an equipotential grounding net, the grounding copper bar in the switch cabinet is connected with the equipotential grounding net, and the safety, meanwhile, the grounding copper bar extends out of the base, is grounded and connected with the main transformer and can be connected with a semitrailer, and safety and reliability are high.

2. The novel prefabricated cabin cable connection structure comprises a limiting groove, a limiting block, an electric push rod, a fixed block, a fixed ring and a fixed hole, wherein when a switch cabinet in a cabin body is replaced or increased, the extending end of the electric push rod is controlled to move to one side close to the center of a base through a control panel, the fixed block is enabled to withdraw from the inside of the fixed hole, the fixed ring is separated from the base, the switch cabinet is further separated from the base, when the switch cabinet is installed, the limiting block is inserted into the limiting groove and then has a limiting effect on the switch cabinet through the limiting block, the fixed ring on the cabin body is sleeved on the base, the extending end of the electric push rod is controlled to move to one side far away from the center of the base through the control panel, the fixed block is inserted into the fixed hole, the fixed ring and the base are fixed together, the switch cabinet is further fixed in the cabin body, and, and then be convenient for the operation personnel to follow with the cubical switchboard that trades or increase in the cabin.

3. This novel prefabricated cabin cable junction structure, through setting up the ventilation hole, cabin internal air passes through the ventilation hole circulation, prevent the heat that the cubical switchboard during operation produced, can't discharge, it is higher to lead to cabin internal portion temperature, and then accelerate the ageing of cabin internal portion cubical switchboard, through setting up the dust guard, the dust guard is the stainless steel filter, play the effect to the dust in the air, prevent that the dust from getting into through ventilation hole entering cubical switchboard in, and simultaneously, through setting up the rain cover, play the effect of keeping off the rain to the ventilation hole, prevent that the rainwater from getting into cabin internal portion through the ventilation hole.

4. This novel prefabricated cabin cable connection structure, through setting up case mouth and chamber door, chamber door and cubical switchboard one-to-one to the setting can regard as the cubical switchboard cable maintenance to use on the upper portion of cable hole, and the operating personnel of being convenient for overhauls the cubical switchboard cable.

5. This novel prefabricated cabin cable junction structure, through setting up the spacing ring, the spacing ring plays limiting displacement to the cubical switchboard, improves the cubical switchboard at the internal stability in cabin, simultaneously, through setting up the gas tank, the spacing ring cover is in the cubical switchboard after, and the inside air of spacing ring passes through the gas tank and discharges, is convenient for overlap the spacing ring on the cubical switchboard on the surface.

Drawings

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

FIG. 2 is an enlarged view taken at A of FIG. 1 in accordance with the present invention;

FIG. 3 is a front view of the structure of the present invention;

FIG. 4 is a side view of the structure of the present invention;

FIG. 5 is a top view of a stop collar of the present invention.

Wherein: the novel switch cabinet comprises a cabinet body 1, a switch cabinet 2, a base plate 3, a limiting groove 4, a limiting block 5, a through hole 6, a heat insulation plate 7, a first cable plate 8, a second cable plate 9, a cable hole 10, a box opening 11, a box door 12, a base 13, a groove 14, a supporting plate 15, an electric push rod 16, a fixing block 17, a sliding hole 18, a fixing ring 19, a fixing hole 20, a partition plate 21, a grounding copper bar 22, a control panel 23, a ventilation hole 24, a dust guard 25, a rain shield 26, a limiting ring 27, a stop dog 28, a handle groove 29 and an air groove 30.

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.

Referring to fig. 1-5, a novel prefabricated cabin cable connection structure comprises a cabin body 1, the cabin body 1 includes a switch cabinet 2, a backing plate 3, a limiting groove 4, a limiting block 5, a through hole 6, a heat insulation plate 7, a first cable plate 8, a second cable plate 9, a cable hole 10, a box opening 11 and a box door 12, the switch cabinet 2 is disposed inside the cabin body 1, the bottom of the switch cabinet 2 is fixedly connected with the upper surface of the backing plate 3, the sum of the height of the switch cabinet 2 and the thickness of the backing plate 3 is equal to the large height of the inner wall of the cabin body 1, the top of the inner wall of the cabin body 1 contacts with the upper surface of the switch cabinet 2 to limit the switch cabinet 2, the cabin body 1 includes a limiting ring 27, the upper surface of the limiting ring 27 is fixedly connected with the top of the inner wall of the cabin body 1, the inner wall of the limiting ring 27 is slidably connected with the surface of the switch cabinet 2, the limiting ring 27, the stability of the switch cabinet 2 in the cabin body 1 is improved, the air groove 30 is arranged in the limiting ring 27, the air groove 30 is arranged on the inner wall of the limiting ring 27, the air groove 30 is arranged, after the limiting ring 27 is sleeved on the switch cabinet 2, the air in the limiting ring 27 is discharged through the air groove 30, the limiting ring 27 is conveniently sleeved on the surface of the switch cabinet 2, the upper surface of the backing plate 3 of the limiting groove 4 is arranged, the inner wall of the limiting groove 4 is matched with the surface of the limiting block 5, the matching gap between the limiting groove 4 and the limiting block 5 is one millimeter, the thickness of the limiting block 5 is equal to the depth of the limiting groove 4, after the limiting block 5 is inserted into the limiting groove 4, the limiting effect is achieved on the switch cabinet 2 through the limiting block 5, the through hole 6 is arranged at the bottom of the left side of the cabin body 1, the inner wall of the through hole 6 is fixedly connected with the surface of the heat, the material has good heat preservation and fire resistance and light weight, so that the novel prefabricated cabin cable connection structure has heat preservation and fire prevention functions, the left side and the right side of the heat preservation plate 7 are respectively fixedly connected with the right side of the first cable plate 8 and the left side of the second cable plate 9, the right side of the first cable plate 8 is fixedly connected with the left side of the cabin body 1, the left side of the second cable plate 9 is fixedly connected with the left side of the inner wall of the cabin body 1, the centers of the first cable plate 8 and the second cable plate 9 are both in the same horizontal plane with the center of the through hole 6, the first cable plate 8 and the second cable plate 9 are adopted at the cable hole 10, the double-layer steel plate structure has high strength and good heat preservation effect, is suitable for most of the domestic terrain and climate conditions, has wide application range, the cable holes 10 are respectively positioned at the left side of the first cable plate 8, the left side of the heat preservation plate 7 and the left side of the second cable plate, the cable hole 10 is designed into and becomes gradient angle structure with the level, do benefit to the operation, make things convenient for the cable to get into, the left side top that case mouth 11 is located the cabin body 1 is seted up, the surface of chamber door 12 mutually supports with the inner wall of case mouth 11, the inside of chamber door 12 includes handle slot 29, handle slot 29 is located the left side of chamber door 12 and is seted up, through setting up handle slot 29, be convenient for operation personnel cubical switchboard 2 doors, the left side of chamber door 12 and the left side of the cabin body 1 are articulated through the hinge, through setting up case mouth 11 and chamber door 12, chamber door 12 and cubical switchboard 2 one-to-one, and set up the upper portion at cable hole 10, can regard as cubical switchboard 2 cable maintenance uses, the operating personnel of being convenient for overhauls.

The bottom of the cabin body 1 comprises a base 13, a groove 14, a supporting plate 15, an electric push rod 16, a fixed block 17, a sliding hole 18, a fixed ring 19, a fixed hole 20, a partition plate 21, a ground copper bar 22 and a control panel 23, wherein the groove 14 is formed on the upper surface of the base 13, the top of the inner wall of the groove 14 is fixedly connected with the surface of the supporting plate 15, the upper surface of the supporting plate 15 is fixedly connected with the bottom of a limiting block 5, the supporting plate 15 supports the switch cabinet 2, the bottom of the electric push rod 16 is fixedly connected with the bottom of the inner wall of the groove 14, one side of the electric push rod 16, which is far away from the center of the base 13, is fixedly connected with one side of the fixed block 17, which is close to the center of the base 13, the left and right movement of the fixed block 17 is controlled by the electric push rod 16, the sliding hole 18 is formed, the surface of the base 13 is connected with the inner wall of the fixing ring 19 in a sliding manner, the fixing holes 20 are formed in the left side and the right side of the fixing ring 19, the inner wall of each fixing hole 20 is connected with the surface of the fixing block 17 in a sliding manner, the fixing block 17 is inserted into the fixing ring 19 to fix the fixing ring 19 and the base 13 together, the fixing block 17 is withdrawn from the fixing ring 19 to separate the fixing ring 19 from the base 13, the surface of the fixing block 17 comprises a stop 28, one side of the stop 28 far away from the center of the base 13 is fixedly connected with one side of the fixing block 17 close to the center of the base 13, the inner wall of the stop 28 is sleeved with the surface of the electric push rod 16, the stop 28 plays a limiting role on the fixing block 17, the top of the inner wall of the fixing ring 19 is fixedly connected with the surface bottom of the cabin body 1, the cabin, the inner wall of the groove 14 is fixedly connected with the bottom of a grounding copper bar 22, the number of the partition boards 21 is two, the two partition boards 21 are symmetrically distributed by taking the grounding copper bar 22 as the center, an electric push rod 16 is separated from the grounding copper bar 22 by the partition boards 21, the bottom of the grounding copper bar 22 penetrates through the base 13 and extends to the bottom of the base 13, the grounding copper bar 22 is electrically connected with the switch cabinet 2, the grounding copper bar 22 is connected end to form an equipotential grounding grid, the grounding copper bar 22 in the switch cabinet 2 is connected with the equipotential grounding grid to ensure the safety of operators of the high-voltage switch cabinet 2, meanwhile, the grounding copper bar 22 extends out of the base 13 to be connected with a main transformer in a grounding way and can be connected with a semitrailer, the safety and the reliability are high, the front surface of the cabin body 1 is fixedly connected with the back surface of the control panel 23, the control panel 23 is respectively electrically connected with the, the right side of the cabin body 1 includes ventilation hole 24, dust guard 25 and rain cover 26, ventilation hole 24 is located the right side of the cabin body 1 and is seted up, 1 interior air of the cabin body circulates through ventilation hole 24, prevent the heat that cubical switchboard 2 during operation produced, can't discharge, it is higher to lead to 1 inside temperature in the cabin body, and then accelerate the ageing of 1 inside cubical switchboard 2 in the cabin body, the inner wall of ventilation hole 24 is connected with dust guard 25's fixed surface, dust guard 25 is the stainless steel filter, play the effect to the dust in the air, prevent that the dust from getting into through ventilation hole 24 entering cubical switchboard 2 in, the right side of the cabin body 1 and the left side fixed connection of rain cover 26, through setting up rain cover 26, play the effect of keeping off the rain to ventilation hole 24, prevent that the rainwater from getting into 1.

When in use, the novel cable connection structure of the prefabricated cabin is fixed on a semi-trailer, a grounding copper bar 22 is connected with a main transformer grounding and semi-trailer, when power is supplied, a cable is inserted into a cable hole 10 and connected with a switch cabinet 2, power is supplied to the cable through the switch cabinet 2, when an operator overhauls the cable of the switch cabinet 2, the door 12 is opened to overhaul the cable of the switch cabinet 2, when the switch cabinet 2 in the cabin body 1 is replaced or increased, the extending end of the electric push rod 16 is controlled to move towards one side close to the center of the base 13 through the control panel 23, the fixed block 17 is withdrawn from the inside of the fixed hole 20, the fixed ring 19 is separated from the base 13, the switch cabinet 2 is further separated from the base 13, when the switch cabinet 2 is installed, after the limit block 5 is inserted into the limit groove 4, the limit function is achieved on the switch cabinet 2 through the limit block 5, the fixed ring 19 on the cabin body 1 is sleeved on the base 13, the control panel 23 controls the extending end of the electric push rod 16 to move towards the side far away from the center of the base 13, so that the fixing block 17 is inserted into the fixing hole 20, the fixing ring 19 is fixed with the base 13, and the switch cabinet 2 is fixed in the cabin 1.

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.