Disclosure of Invention
The invention aims to provide a laparoscope puncture outfit with a fixing device, which solves the problems in the background art.
In order to achieve the above purpose, the present invention provides the following technical solutions:
a laparoscopic puncture instrument with a fixing device, comprising:
The outer sheath structure comprises a puncture seat and a puncture tube which is arranged at one end of the puncture seat and communicated with the puncture seat;
Fixing device locates the puncture outer wall, includes:
The first fixing part is movably sleeved on the outer wall of the puncture tube and is used for contacting with the outer wall of the abdominal cavity of the patient;
The balloon fixing part comprises an inner ring movably sleeved on the outer wall of the puncture tube and positioned below the fixing part and an annular air bag arranged on the outer wall of the inner ring, and the annular air bag is used for being in contact with the inner wall of the abdominal cavity of a patient;
the driving part comprises an air bag driving unit and an inner ring driving unit, wherein the air bag driving unit is used for driving the annular air bag to expand, and the inner ring driving unit is used for driving the inner ring to move towards the first fixing part;
the inner ring driving unit includes:
The two groups of rope bodies, one ends of the two groups of rope bodies extend to the inner cavity of the inner ring, the other ends extend to the puncture seat and are wound on the outer wall of the manual rotating rod, and one end of the manual rotating rod II penetrates through the side wall of the puncture seat to be manually rotated by an operator;
the locking piece is arranged on the inner ring and used for fixing the inner ring and the puncture tube, and the locking piece is also connected with one end of the rope body so as to release the fixing state of the inner ring and the puncture tube when the rope body is wound by the manual rotating rod.
A further improvement is that the first fixing part comprises:
the movable block is sleeved on the outer wall of the puncture tube through threads;
The silica gel disc is arranged at one end of the movable block facing the saccule fixing part and movably sleeved outside the puncture tube.
The improvement lies in still including setting up in the puncture pipe outer wall and supplying the annular notch that the inner ring emboliaed, vertical notch has been seted up to the outer wall bilateral symmetry of annular notch, and the one end of vertical notch extends to puncture pipe outer wall upper end, two sets of the rope body is in two vertical notch respectively.
A further improvement is that the airbag drive unit includes:
The two groups of connecting air pipes are respectively positioned in the two vertical notches, one end of the connecting air pipes penetrates through the inner ring and then is communicated with the annular air bag, the other end of the connecting air pipes extends into the puncture seat and is wound on the outer wall of the manual rotating rod I and then is communicated with the communication seat, one end of the manual rotating rod I penetrates through the side wall of the puncture seat, the communication seat is positioned at the outer side of the puncture seat and is communicated with one end of the three-way valve through the air supply pipe, the other two ends of the three-way valve are respectively communicated with the mounting air pipe and the air inlet pipe, and the air inlet pipe is communicated with the puncture pipe;
the detection piece is arranged on the communication seat and is communicated with the connecting air pipe through the branch pipe.
The improvement is that the top wall of the vertical notch, the outer wall of the puncture seat and the inner wall of the puncture seat are all provided with guide pieces for guiding the connecting air pipe and the rope body.
A further improvement is that the detecting member includes:
the valve seat is communicated with the branch pipe, one end of the valve seat is detachably communicated with a transparent bottle, and an indicator which generates color change after being contacted with gas is arranged in the transparent bottle;
the valve core is movably arranged in the valve seat inner cavity, and one end of the valve core is connected with the valve seat inner wall through a spring;
The bolt is inserted on the valve seat and penetrates through the valve core and is used for fixing the valve core;
After the bolt is separated from the valve core, when the annular air bag extrudes the inner wall of the abdominal cavity of the patient, the gas in the annular air bag drives the valve core to move into the transparent bottle to be contacted with the indicator, so that the indicator generates color change.
A further improvement is that the locking member comprises:
The moving block is movably arranged in the inner cavity of the inner ring and connected with one end of the rope body, one end of the moving block is connected with the inner wall of the inner ring through an elastic piece I, and one side of the moving block is provided with an arc-shaped convex part;
The locking block is movably inserted into the inner wall of the inner ring, one end of the locking block is in sliding abutting connection with the arc-shaped convex part, the other end of the locking block extends into the vertical notch, and the locking block is connected with the inner wall of the inner ring through the second elastic part and is used for driving the locking block to move towards the inner ring cavity when the locking block is staggered with the arc-shaped convex part;
the slots are uniformly arranged on the surface wall of the vertical notch in a vertical array, and the other ends of the locking blocks are inserted.
The improvement is that the sheath-core structure is inserted into the outer sheath structure, and the sheath-core structure comprises:
the core rod is provided with a puncture head at one end and a cover body at the other end, and the puncture head is a transparent puncture head;
The cap body is movably sleeved on the outer side of the core rod, a second sealing piece for sealing the joint of the core rod and the cap body is arranged on the inner wall of the cap body, one end of the cap body is detachably connected with the puncture seat through a first fastening structure, and the other end of the cap body is detachably connected with the cap body through a second fastening structure;
The puncture seat is provided with a through hole for the core rod to be inserted and communicated with the puncture tube, and a sealing piece I is arranged in the through hole and above the air inlet tube.
The improvement lies in, the jack that runs through with lid inner chamber and core bar inner chamber intercommunication has been seted up at the top of lid, the assembly mouth with lid inner chamber intercommunication has been seted up to the outer wall of one side of lid, and the assembly mouth internal rotation is equipped with presses and hold the piece, it has seted up the arc mouth to press the one end that holds the piece to be located the lid inner chamber, and the arc mouth inner wall is equipped with the flexible piece of arc, it compresses tightly the tubular medical instrument that passes the jack to press the piece rotatable through the arc mouth.
Compared with the prior art, the invention has the beneficial effects that:
According to the invention, the balloon fixing part and the first fixing part in the fixing device can be respectively contacted with the inner and outer surfaces of the abdominal cavity of a patient, so that the puncture tube is limited to move in the abdominal cavity of the patient, the use risk caused by shaking of the puncture outfit is reduced, and meanwhile, the driving part is arranged to drive the annular air bag to expand and then adjust the position of the driving part on the outer wall of the puncture tube;
The driving part is also provided with the locking piece, the inner ring can be fixed with the puncture tube after the inner ring is driven to drive the annular air bag to a required position, the fixing strength of the annular air bag and the pair of puncture tubes of the fixing part is ensured, and the risk caused by unstable puncture tube fixing is further prevented;
The driving part of the invention is also provided with the detection part, after the inner ring is driven to drive the annular air bag to extrude the inner wall of the abdominal cavity of the patient, the gas in the annular air bag can enter the valve seat through the connecting gas pipe and the branch pipe to drive the valve core to move, and then enters the transparent bottle to be contacted with the indicator, so that the indicator generates color change to remind an operator, the operator can know the position of the annular air bag, the error of manual judgment is reduced, and the use safety of the puncture outfit is greatly improved.
Drawings
FIG. 1 is a schematic view of the puncture outfit according to the present invention;
FIG. 2 is a schematic view of the structure of the sheath according to the present invention;
FIG. 3 is a partial cross-sectional view of the structure of FIG. 2 in accordance with the present invention;
FIG. 4 is an enlarged view of the structure A of FIG. 3 in accordance with the present invention;
FIG. 5 is a schematic view of a partial structure of an inner cavity of a puncture seat according to the present invention;
FIG. 6 is a cross-sectional view of a test element according to the present invention;
FIG. 7 is a schematic structural view of a sheath core according to the present invention;
fig. 8 is a cross-sectional view of the structure of fig. 7 in accordance with the present invention.
100, An outer sheath structure; 101, puncture seat, 102, puncture tube, 103, annular notch, 104, vertical notch, 105, first sealing element, 200, sheath-core structure, 201, core bar, 202, puncture head, 203, cap, 204, first fastening structure, 205, second fastening structure, 206, cover, 207, jack, 208, holding block, 209, arc opening, 210, second sealing element, 300, fixing device, 301, movable block, 302, silica gel disc, 303, annular air bag, 304, inner ring, 305, movable block, 306, arc protruding part, 307, connecting air tube, 308, rope, 309, first manual rotating rod, 310, second manual rotating rod, 311, communicating seat, 312, mounting air tube, 313, three-way valve, 314, air supply tube, 315, transparent bottle, 316, valve seat, 317, valve core, 318, spring, 319, plug, 320, locking block, 321, slot.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 1-5, a laparoscopic puncture device with a fixing device, comprising:
the outer sheath structure 100 comprises a puncture seat 101 and a puncture tube 102 which is arranged at one end of the puncture seat 101 and is communicated with the puncture seat 101, and the puncture tube 102 can be used as a passage for surgical instruments to enter the abdominal cavity of a patient after being inserted into the abdominal cavity of the patient;
A sheath-core structure 200 for insertion into the outer sheath structure 100;
The fixing device 300, locate the outer wall of puncture tube 102, include:
the first fixing part is movably sleeved at the upper end of the outer wall of the puncture tube 102 and is used for contacting with the outer wall of the abdominal cavity of a patient;
The balloon fixing part comprises an inner ring 304 movably sleeved on the outer wall of the puncture tube 102 and positioned below the fixing part, and an annular air bag 303 arranged on the outer wall of the inner ring 304, wherein the annular air bag 303 is used for being contacted with the inner wall of the abdominal cavity of a patient, after the puncture outfit is inserted into the abdominal cavity of the patient, the first fixing part is adjusted to be contacted with the outer wall of the abdominal cavity of the patient, and then the annular air bag 303 is expanded and adjusted to be contacted with the inner wall of the abdominal cavity of the patient, so that the puncture tube 102 is limited to slide outwards or inwards, and the risk caused by unstable fixation of the puncture outfit in operation is reduced;
The driving part comprises an air bag driving unit and an inner ring driving unit, wherein the air bag driving unit is used for driving the annular air bag 303 to expand, the inner ring driving unit is used for driving the inner ring 304 to move towards the first fixing part, and as the depth of the abdominal wall muscles and fascia of a patient is inconsistent, the annular air bag 303 can be expanded firstly after the puncture outfit is inserted into the abdominal cavity of the patient, and then the position of the annular air bag 303 on the puncture tube 102 is adjusted to enable the annular air bag 303 to be in contact with the inner wall of the abdominal cavity of the patient.
Preferably, the first fixing portion of the present embodiment includes:
The movable block 301 is sleeved on the outer wall of the puncture tube 102 in a threaded manner, and an external thread groove structure is formed in the outer wall of the puncture tube 102, so that the movable block 301 can conveniently move to a required position on the outer wall of the puncture tube 102, and the puncture outfit can be better fixed at the abdominal cavity of a patient;
The silica gel disc 302 is arranged at one end of the movable block 301 facing the balloon fixing part and movably sleeved outside the puncture tube 102, the silica gel disc 302 is made of silica gel material, and the contact with the abdominal cavity outer wall of a patient can not cause discomfort to the patient.
As an advantage, the outer sheath structure 100 of the present embodiment further includes an annular notch 103 that is opened on the outer wall of the puncture tube 102 and into which the inner ring 304 is sleeved, and the outer diameter of the inner ring 304 is smaller than or equal to the outer diameter of the puncture tube 102, so that the inner ring can enter the abdominal cavity of a patient along with the puncture tube 102, two sides of the outer wall of the annular notch 103 are symmetrically opened with vertical notches 104, and one end of the vertical notch 104 extends to the upper end of the outer wall of the puncture tube 102.
Preferably, the airbag driving unit of the present embodiment includes:
The two groups of connecting air pipes 307 respectively positioned in the two vertical notches 104 prevent the connecting air pipes 307 from influencing the puncture outfit to be inserted into the abdominal cavity of a patient, the discomfort to the patient is avoided, one ends of the two groups of connecting air pipes 307 penetrate through the inner ring 304 and are communicated with the annular air bag 303, the other ends extend to the puncture seat 101, are wound on the outer wall of the manual rotating rod I309, penetrate through the outer wall of the puncture seat 101 and are communicated with the communicating seat 311, one end of the manual rotating rod I309 penetrates through the side wall of the puncture seat 101 for manual rotation of an operator, one end of the manual rotating rod I309 penetrates through the side wall of the puncture seat 101 and is provided with a hand wheel or disc-shaped structure for manual rotation of the operator, the communicating seat 311 is arranged on the outer wall of the puncture seat 101, the communicating seat 311 is communicated with one end of the three-way valve 313 through the air supply pipe 314, and the other two ends of the three-way valve 313 are respectively communicated with the mounting air pipe 312 used for connecting an external air source and the air inlet pipe communicated with the puncture tube 102;
The external air source can be inflatable equipment, and the three-way valve 313 is of a conventional structure in the art, and the three-way valve 313 is operated to control the communication between the mounting air pipe 312 and the air inlet pipe or the communication between the mounting air pipe 312 and the air supply pipe 314;
the working principle of the air bag driving unit is as follows:
Inserting the puncture tube 102 into the abdominal cavity of a patient through the sheath-core structure 200, controlling the three-way valve 313 to enable the mounting air tube 312 to be communicated with the air supply tube 314, simultaneously connecting the mounting air tube 312 with an external air source, enabling the air to enter the mounting air tube 312 and then enter the communicating seat 311, enabling the air to enter the annular air bag 303 through the connecting air tube 307 to expand the annular air bag 303, controlling the three-way valve 313 to enable the mounting air tube 312 to be not communicated with the air supply tube 314 after the annular air bag 303 is expanded, controlling the three-way valve 313 to enable the mounting air tube 312 to be communicated with the air supply tube 314 when the air in the annular air bag 303 is exhausted, and separating the external air source from the mounting air tube 312;
The detecting piece is arranged on the communicating seat 311 and communicated with the connecting air pipe 307 through a branch pipe, and is used for detecting whether the annular air bag 303 is in contact with the inner wall of the abdominal cavity of the patient.
Preferably, the inner ring driving unit of the present embodiment includes:
The two groups of ropes 308 are respectively positioned in the two vertical notches 104, the rope 308 is prevented from influencing the puncture outfit to be inserted into the abdominal cavity of a patient, the rope 308 is a stainless steel wire rope or a tungsten wire rope, and the like, one ends of the two groups of ropes 308 extend to the inner cavity of the inner ring 304, the other ends extend into the puncture seat 101 and are wound on the outer wall of the manual rotating rod II 310, one end of the manual rotating rod II 310 penetrates through the side wall of the puncture seat 101 to be manually rotated by an operator, and one end of the manual rotating rod II 310 penetrating through the side wall of the puncture seat 101 is provided with a hand wheel or a disc-shaped structure to be manually rotated by the operator;
And the locking piece is arranged on the inner ring 304 and used for fixing the inner ring 304 and the puncture tube 102, and is also connected with one end of the rope 308 so as to release the fixing state of the inner ring 304 and the puncture tube 102 when the second manual rotating rod 310 winds the rope 308.
The inner ring driving unit works on the principle that after the annular air bag 303 is inflated, the rope 308 can be wound by rotating the manual rotating rod II 310, so that the locking piece is released from the fixed state of the inner ring 304 and the puncture tube 102 by the rope 308, meanwhile, the inner ring 304 is pulled to drive the annular air bag 303 to move towards the direction close to the silica gel plate 302, meanwhile, one end of the connecting air pipe 307 can be wound by rotating the manual rotating rod I309, the connecting air pipe 307 cannot be bent in the abdominal cavity of a patient, the subsequent rope 308 is wound, the inner ring 304 is limited to move, the connecting air pipe 307 is wound on the manual rotating rod I309, when one end of the annular air bag 303 is connected with the winding connecting air pipe 307, the other end of the connecting air pipe 307 is wound, and after the annular air bag 303 is pulled to move by the rope 308, the annular air bag 303 is tightly attached to the inner abdominal cavity of the patient, the inner ring 304 is wound, and the locking piece is reset to fix the puncture tube 102 by the inner ring 304 due to the fact that the inner ring 304 is limited by the connecting air pipe 307.
As a preferred embodiment, the top wall of the vertical slot 104, the outer wall of the puncture seat 101 and the inner wall of the puncture seat 101 are provided with guiding members for guiding the connecting air tube 307 and the rope 308, and the guiding members are of structures such as micro pulleys, limiting blocks or limiting sheets, so that the connecting air tube 307 and the rope 308 can move smoothly and accurately along a predetermined path, and meanwhile, the connecting air tube 307 and the rope 308 are positioned in the vertical slot 104 and cannot cause discomfort to a patient.
Referring to fig. 6, preferably, the detecting member of the present embodiment includes:
The valve seat 316, it is communicated with branch pipe, for example, as can be seen from fig. 6, the vertical section of the inner cavity of the valve seat 316 is T-shaped, its upper end diameter of inner cavity is greater than its lower end diameter of inner cavity, branch pipe is communicated with lower end of inner cavity of the valve seat 316 specifically, one end of the valve seat 316 is detachably communicated with transparent bottle 315, there is indicator which produces color change after contacting with gas in the transparent bottle 315, for example, oxygen indicator, etc., as shown in fig. 6, the transparent bottle 315 is reversely connected with top end of the valve seat 316 in a detachable way, it is noted that if the transparent bottle 315 is reversely connected with one end of the valve seat 316 in a detachable way, the bottle mouth of the transparent bottle 315 can be provided with an interception net to prevent the indicator from entering into the valve seat 316;
The valve core 317 is movably arranged in the inner cavity of the valve seat 316, one end of the valve core 317 is connected with the inner wall of the valve seat 316 through a spring 318, as shown in fig. 6, the valve core 317 is positioned at a step port formed between the upper end of the inner cavity of the valve seat 316 and the lower end of the inner cavity, and the diameter of the valve core 317 is smaller than the diameter of the upper end of the inner cavity of the valve seat 316 and larger than the diameter of the lower end of the inner cavity of the valve seat 316;
The plug 319 is inserted on the valve seat 316 and penetrates through the valve core 317, and is used for fixing the valve core 317, when the annular air bag 303 is inflated by injecting air, the valve core 317 cannot move towards the upper end of the inner cavity of the valve seat 316 under the action of the plug 319, and gas is prevented from entering the transparent bottle 315;
When the annular balloon 303 is inflated to drive the inner ring 304 to move, the movable plug 319 moves away from the valve core 317 (but the plug 319 does not separate from the valve seat 316), at this time, the valve core 317 is in a movable state, and when the annular balloon 303 contacts and is pressed against the inner wall of the abdominal cavity of the patient, the gas in the annular balloon 303 enters the valve seat 316 through the connecting gas pipe 307 and the branch pipe to drive the valve core 317 to move, and then the gas enters the transparent bottle 315 to contact with the indicator, so that the indicator generates a color change.
Preferably, the locking member of the present embodiment includes:
The moving block 305 is movably arranged in the inner cavity of the inner ring 304 and connected with one end of the rope 308, one end of the moving block is connected with the inner wall of the inner ring 304 through an elastic member I, for example, a spring, and the elastic member I is used for driving the moving block 305 to reset when the rope 308 is unreeled, and one side of the moving block 305 is integrally provided with an arc-shaped convex part 306;
the locking block 320 is movably inserted into the inner wall of the inner ring 304, one end of the locking block 320 is embedded with a ball for sliding contact with the arc-shaped convex part 306, the other end of the locking block 320 extends into the vertical notch 104, the locking block 320 is connected with the inner wall of the inner ring 304 through a second elastic element, and the second elastic element is a spring, for example, and is used for driving the locking block 320 to move towards the inner cavity of the inner ring 304 when the ball of the locking block 320 is staggered with the arc-shaped convex part 306;
The plurality of groups of slots 321 are uniformly arranged on the surface wall of the vertical notch 104 in a vertical array for inserting the other end of the locking block 320.
The working principle of the locking piece is that after the annular air bag 303 is expanded, the manual rotating rod I309 and the manual rotating rod II 310 are rotated to retract the rope 308, the locking piece 320 is positioned in the slot 321, so that the moving piece 305 is pulled to move by the rope 308, the arc convex part 306 on the moving piece 305 is staggered with the ball of the locking piece 320, the locking piece 320 is separated from the slot 321 under the action of the elastic piece II, at the moment, the inner ring 304 is in an active state, the manual rotating rod I309 and the manual rotating rod II 310 are synchronously rotated to retract the rope 308 and the connecting air pipe 307, the inner ring 304 drives the annular air bag 303 to move, after the color change of the indicator in the transparent bottle 315 is observed, the manual rotating rod II 310 is reversely rotated to retract the rope 308, at the moment, under the action of the elastic piece I, the moving piece 305 is reset, the arc convex part 306 corresponds to the ball of the locking piece 320 again, the other end of the locking piece 320 is driven to be inserted into the corresponding slot 321, the fixing of the inner ring 304 and the puncture tube 102 is completed, and the annular air bag 303 and the puncture tube 102 are effectively limited to move by the fixed part I.
Referring to fig. 7 to 8, the sheath-core structure 200 of the present embodiment preferably includes:
The outer diameter of the core rod 201 can be matched with the inner diameter of the puncture tube 102, the puncture head 202 is a transparent puncture head, so that one end of some medical instruments can enter the puncture head 202 to perform shooting and other works, the puncture head 202 is conical and is used for better cutting a knife edge, so that the puncture tube 102 enters an abdominal cavity, the phenomena of fascia injury and bleeding of a puncture part during puncture are reduced, the puncture is safe and controllable, and the puncture safety is increased;
the cap body 203 is movably sleeved on the outer side of the core rod 201, a second sealing element 210 for sealing the joint of the core rod 201 and the cap body 203 is arranged on the inner wall of the cap body 203, the second sealing element 210 is made of rubber material, one end of the cap body 203 is detachably connected with the puncture seat 101 through a first fastening structure 204, the other end of the cap body 203 is detachably connected with the cover body 206 through a second fastening structure 205, and the first fastening structure 204 and the second fastening structure 205 are of conventional structures in the field and are not described in detail;
The puncture seat 101 is provided with a through hole for the core rod 201 to be inserted and communicated with the puncture tube 102, a first sealing element 105 is arranged in the through hole and above the air inlet pipe, and the first sealing element 105 is made of elastic rubber materials.
After the puncture tube 102 is fixed in the abdominal cavity of a patient through the fixing device 300, the air can be supplied to the mounting air tube 312 through an external air source, and the air enters the puncture tube 102 through the mounting air tube 312 and the air inlet tube, so that the abdominal cavity of the patient is inflated to become pneumoperitoneum, and then the air injection is stopped so that the abdominal cavity of the patient keeps pneumoperitoneum;
When the puncture tube is used, the core rod 201 and the puncture head 202 can be pulled out through the cover 206, the puncture tube 102 is left in the abdominal cavity of a patient, the puncture tube 102 can be used as an instrument channel, the instrument can be inserted into the abdominal cavity of the patient through the puncture tube 102 for operation, and in the operation process, if a large specimen needs to be taken out, the cap 203 is removed, so that the large specimen can be taken out from the through hole.
As a preferred embodiment, the top of the cover 206 of the present embodiment is penetrated and provided with a jack 207 which is communicated with the inner cavity of the cover 206 and the inner cavity of the core rod 201, the outer wall of one side of the cover 206 is provided with an assembly port which is communicated with the inner cavity of the cover 206, the assembly port is rotationally provided with a pressing block 208, the vertical section of the pressing block 208 is L-shaped, the pressing block 208 is rotationally connected with the inner wall of the assembly port by adopting a rotating shaft structure arranged in the middle part of the pressing block 208, one end of the pressing block 208, which is positioned in the inner cavity of the cover 206, is provided with an arc-shaped port 209, the inner wall of the arc-shaped port 209 is provided with an arc-shaped flexible block, the pressing block 208 can rotationally press a tubular medical instrument which passes through the jack 207 through the arc-shaped port 209, for example, when the pressing block 208 rotates to a preset angle, the arc-shaped port 209 coincides with the axis of the jack 207.
The operation principle is that when the image of the inside of the abdominal cavity of the patient needs to be shot, after the puncture tube 102 is fixed in the abdominal cavity of the patient through the fixing device 300, the core rod 201 and the puncture head 202 are not pulled out temporarily, a tubular medical appliance such as a laparoscope is inserted from the insertion hole 207, one end of the laparoscope with the miniature camera head is arranged at the puncture head 202 to collect the image of the abdominal cavity of the patient, in order to prevent the laparoscope from moving, the pressing block 208 is pressed to enable the pressing block 208 to rotate, and the pressing block 208 compresses the outer wall of the laparoscope at the insertion hole 207 through the arc-shaped opening 209 and the arc-shaped flexible block, so that the laparoscope is not easy to move when in use.
Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.