CN204694239U - Zero-bit memory pump injection type inclusion strainometer - Google Patents

Abstract

The utility model provides a zero-position memory pump-injection cladding strain gauge with greatly improved installation and positioning accuracy, which includes a mounting part and a mounting rod for pushing the mounting part, and the mounting part includes a measuring line and sequentially connected orifices The end cover, the base pipe of the package body, the end cover of the hole bottom, the end cover of the hole and the end cover of the hole bottom are all equipped with a sealing ring and sequentially connected glue inlet holes, glue guide holes, and annular glue guide grooves on the outer surface , the rubber guide groove covers the rubber expansion bag, the glue inlet hole of the orifice end cover is connected with the glue inlet hole of the hole bottom end cover; the hole bottom end cover is provided with a pressure regulating hole and a glue outlet hole, and the pressure regulating hole is provided The pressure regulating component that controls the connection between the glue outlet hole and the glue guide hole. The outlet of the glue outlet hole is located on the outer surface of the end cover at the bottom of the hole, and is located on the left side of the rubber expansion bag of the end cover at the bottom of the hole. The utility model improves the reliability and effectiveness of the strain measurement data and improves the installation survival rate.

Description

Zero memory pump injection inclusion body strain gauge

technical field

The utility model relates to the technical field of measuring devices for strain and ground pressure in rock and soil and mining engineering, in particular to a zero-position memory pumping type inclusion strain gauge, which is suitable for actual measurement of original rock stress and excavation dynamics based on hole wall strain. Pressure distribution measurement, rockburst and coal and gas outburst strain precursor monitoring, etc.

Background technique

Actual measurement or process monitoring of hole wall strain is an important indicator for in-situ rock stress testing, mining dynamic pressure testing, rockburst and coal and gas outburst precursor detection, and is extremely important for tunnel excavation and mining construction.

At present, the strain rosettes of hollow inclusion strain gauges used for in-situ rock stress measurement include three types: 9 strain gauges, 13 strain gauges and 12 strain gauges, which cannot achieve repeated zeroing of each channel and are limited by limited The number of strain gauge channels, a single strain gauge can only measure the strain of a single hole in one cycle. The installation mechanism is to seal the resin by inserting the rubber ring into the hole. If the hole wall seeps water or is too rough, a potting cavity will be formed. If the rubber ring wears too much, the hole will not be sealed tightly, and the resin will be lost, resulting in lower installation and positioning accuracy. As a result, the reliability and validity of the strain measurement data are not high, and the installation survival rate is low.

Utility model content

The purpose of this utility model is to solve the above-mentioned problems in the existing technology, and propose a zero-position memory pump injection inclusion strain gauge with greatly improved installation and positioning accuracy, so that the reliability and effectiveness of strain measurement data can be improved. The installation survival rate is improved.

The purpose of this utility model can be achieved through the following technical solutions:

A zero-position memory pump injection type cladding strain gauge, which includes a mounting part and a mounting rod for pushing the mounting part. The mounting part includes a measuring line and an orifice end cover, a cladding base pipe, and a hole bottom end connected in sequence. The cover, the end cover of the hole and the end cover of the hole bottom are all equipped with a sealing ring and sequentially connected glue inlet holes, glue guide holes, and annular glue guide grooves on the outer surface, covering the rubber guide grooves with elastic rubber expansion The two ends of the capsule are sealed and fixed on the outer surface so that the capsule and the rubber guide groove form a sealed expansion chamber, the sealing ring of the end cap of the orifice is located on the left side of the capsule, and the end cap of the hole bottom The sealing ring is located on the right side of the rubber expansion bag, and the glue inlet hole of the orifice end cover is connected with the glue inlet hole of the hole bottom end cover; Connected glue hole, the pressure regulating hole is equipped with a pressure regulating component for controlling the connection between the glue hole and the glue guide hole, the outlet of the glue hole is located on the outer surface of the end cover at the bottom of the hole, and is located The left side of the capsule.

Compared with the prior art, the utility model has the following advantages:

The sealing ring can realize the purpose of sweeping holes, and at the same time prevent foreign matter from entering the area between the two sealing rings, so that this area is conducive to perfusion of glue; the pressure set by the pressure regulating component can control the pressure of the glue, and the perfusion pressure can be controlled by the pressure regulating component. Pre-set, the infusion process is roughly as follows. Firstly, the expansion of the rubber bladder not only realizes the sealing of the hole, but also realizes the concentricity and coaxiality of the installation part and the drilling hole. Then the pressure breaks through the pressure set by the pressure regulating component, and the continuous injection of glue will Let the glue enter the area between the two rubber expansion bladders through the glue outlet hole, and pour through the pressure, which is beneficial to waterproof and avoids the formation of hardened cavities. Under the action of expansion pressure, the axis of the installation part coincides with the axis of the drilling hole, which is conducive to measuring the strain flower in the line. The uniform distribution of pasting, so as to achieve the substantial reduction of perfusion cavities, greatly improve the installation positioning accuracy, the purpose of improving the reliability and effectiveness of strain measurement data; in a word, the utility model has the advantages of greatly improving the installation positioning accuracy, so that The reliability and validity of the strain measurement data are improved, and the installation survival rate is improved.

As an improvement, the measurement circuit includes three sets of four-piece strain rosettes that are evenly distributed in the circumferential direction and potted on the outer ring surface of the enclosure base pipe, and temperature compensation and zeroing strain rosettes with the same sensitivity coefficient buried in the tail cavity of the orifice end cap. Each strain rosette is electrically connected with fifteen-core shielded wires respectively, and the fifteen-core shielded wires are pulled out through the first cable hole arranged on the end cover of the hole, so that the multi-hole measurement of the single strain gauge at the same period can be realized.

As an improvement, the installation rod includes a rod connection sleeve, a body connection sleeve detachably connected to the left side of the orifice end cover, and a second cable hole and a rubber hose hole are provided inside the rod connection sleeve and the body connection sleeve. The main body connection sleeve is also provided with a horizontally split pipe fixing screw hole through the rubber hose hole. The fixing pipe screw hole is provided with a fixing pipe screw for fixing the rubber injection pipe plugged into the glue inlet hole. The right end of the body connection sleeve is open. Due to the orientation groove of the push installation part, the left part of the orifice end cover is provided with an orientation pin that slides and fits with the orientation groove. The orientation pin is located on the left side of the sealing ring of the orifice end cover. Both the wire and the injection tube are protected in the installation rod, which avoids the scratching of the two by the wall of the installation hole, and the fixing screw is set to ensure the reliable exit of the injection tube with the body connecting sleeve.

As an improvement, the glue inlet hole of the orifice end cover is a glue inlet through hole, the glue inlet hole of the end cover at the bottom of the hole is a glue inlet blind hole, and the two ends of the glue inlet through hole are respectively threaded to connect two copper pipes, denoted as The left copper pipe and the right copper pipe, the left part of the left copper pipe is plugged with the glue injection pipe, the right part of the right copper pipe is connected with the glue-feeding blind hole, and the outer ring surface of the orifice end cover is from the left To the right, there are ring-shaped blocking ring grooves, the first binding groove, the rubber guide groove, and the second binding groove in sequence. The portion adjacent to the right end of the cable hole is uniformly distributed with three threading holes in the circumferential direction, so that the structure is compact, simple, reliable and low in cost.

As an improvement, the two ends of the inclusion base pipe are processed into steps that match the hole end cap and the hole bottom end cap respectively, and the inclusion base pipe is a seamless steel pipe or an aluminum alloy pipe or a copper pipe or a ring with a fixed diameter. Oxygen resin pipe, PE pipe or PVC pipe. In this way, seamless steel pipe, thick-walled aluminum pipe, and copper pipe are used to form hard inclusions, and epoxy resin pipes, PE pipes, and PVC pipes can be used to form soft inclusions. In the calculation, the thickness, elastic modulus and Poisson's ratio of the inclusion base pipe can be involved, respectively deal with hard rock and soft rock, the elastic deformation range of the measured hole wall is wider, and the measurement accuracy is higher.

As an improvement, the pressure regulating hole is provided with an internal thread section and a top pressure section in sequence. The outer ring surface of the end cover is sequentially opened with ring-shaped sealing ring grooves, the first binding groove, the rubber guide groove, the second binding groove, and the rubber ring groove from left to right. The glue outlet groove is connected with the outlet of the glue outlet hole. ;The right end of the end cover at the bottom of the hole is a tapered guide head, so that the structure is compact, simple and reliable, and the cost is low.

Description of drawings

Fig. 1 is the structural representation of the utility model embodiment;

Fig. 2 is a sectional view along I-I direction in Fig. 1;

Fig. 3 is the sectional view of II-II in Fig. 1;

Fig. 4 is the structural representation of orifice end cap;

Fig. 5 is the structural representation of hole bottom end cap;

Figure 6 is a schematic diagram of the pumping stage;

Figure 7 is a schematic diagram of the installation;

As shown in the figure, 1. Mounting rod, 2. Connecting screw, 3. Fifteen-core shielded wire, 4. Rubber injection tube, 5. Rod connecting sleeve, 6. Body connecting sleeve, 7. Fixing screw, 8. Hole End cap, 9. Orientation pin, 10. Potting resin, 11.1, Left copper tube, 11.2, Right copper tube, 12. Sealing ring, 13. Temperature compensation and zeroing strain rosette, 14. Iron hoop wire, 15, Rubber expansion capsule, 16, strain flower wire group, 17, package body base pipe, 18, four-piece strain rosette, 19, hole bottom end cover, 20, pressure adjusting screw, 21, compression spring, 22, valve ball, 24 , the first cable hole, 25, the rubber hose hole, 26, the fixed pipe screw hole, 27, the orientation groove, 28, the tail cavity, 29, the pin hole, 30, the sealing ring groove, 30.1, the first binding groove, 30.2, the second Second binding groove, 31, the second cable hole, 32, the through hole for glue feeding, 33, the glue guiding groove, 34, the glue guiding hole, 35.1, the third binding groove, 35.2, the fourth binding groove, 36, the threading hole, 37 , front cavity of the orifice end cover, 38, steps, 39, inner cavity of the package, 40, glue outlet groove, 41, glue inlet blind hole, 42, guide head, 44, glue outlet hole, 45, pressure regulating hole, 46, Pressure potting glue, 47, measured drilling.

Detailed ways

The following are specific embodiments of the utility model and in conjunction with the accompanying drawings, the technical solution of the utility model is further described, but the utility model is not limited to these embodiments.

The zero-position memory pumping type inclusion strain gauge given in this embodiment includes an installation part and an installation rod 1 for pushing the installation part. The base pipe 17, the hole bottom end cover 19, the hole end cover 8 and the hole bottom end cover 19 are all provided with a sealing ring 12 and sequentially connected glue inlet holes, glue guide holes 34, and annular glue guide holes arranged on the outer surface. Groove 33 covers the elastic rubber bladder 15 around the rubber guide groove 33, and the two ends of the rubber bladder 15 are sealed and fixed on the outer surface so that the rubber bladder 15 and the rubber guide groove 33 form a sealed expansion cavity, and the orifice The sealing ring 12 of the end cap 8 is located on the left side of the rubber bladder 15, the sealing ring 12 of the end cover 19 at the bottom of the hole is located on the right side of the rubber bladder 15, and the glue inlet hole of the orifice end cover 8 is connected to the hole bottom end cover 19. The glue inlet holes are connected to each other; the hole bottom cover 19 is provided with a pressure regulating hole 45 connected with the glue guide hole 34, and a glue outlet hole 44 connected with the pressure regulating hole 45, and the pressure regulating hole 45 is provided with a hole 44 for controlling the glue outlet. The outlet of the glue outlet hole 44 is located on the outer surface of the end cover 19 at the bottom of the hole, and is located on the left side of the rubber expansion bag 15 of the end cover 19 of the hole bottom.

The sealing ring 12 adopts a rubber ring.

The measurement circuit includes three sets of four-piece rosettes 18 uniformly distributed in the circumferential direction and potted on the outer ring surface of the encapsulation base pipe 17, and temperature compensation and zeroing rosettes with the same sensitivity coefficient buried in the tail cavity 28 of the orifice end cover 8 13. Each strain rosette is electrically connected to the fifteen-core shielded wire 3 respectively, and the fifteen-core shielded wire 3 is pulled out through the first cable hole 24 provided on the hole end cover 8 .

The installation rod 1 includes a rod connection sleeve 5 and a body connection sleeve 6 detachably connected to the left side of the orifice end cover 8. The surface layer of the installation rod 1 is connected to the rod connection sleeve 5 and the body connection sleeve 6 through connecting screws 2. , the inside of the rod connecting sleeve 5 and the inside of the body connecting sleeve 6 are provided with a second cable hole 31 and a rubber hose hole 25, and the inside of the body connecting sleeve 6 is also provided with a fixed pipe screw hole 26 that is horizontally split through the rubber hose hole 25 , the fixed pipe screw hole 26 is provided with a fixed pipe screw 7 for fixing the injection pipe 4 plugged into the glue inlet hole, the right end of the body connecting sleeve 6 is provided with an orientation groove 27 for pushing the installation part, and the left side of the orifice end cover 8 The side part is provided with an orientation pin 9 slidingly matched with the orientation groove 27, and the orientation pin 9 is located on the left side of the sealing ring 12 of the orifice end cover 8, and the orientation pin 9 is connected with the pin hole 29 provided on the orifice end cover 8.

The glue inlet hole of the orifice end cover 8 is a glue inlet through hole 32, the glue inlet hole of the end cover 19 at the bottom of the hole is a glue inlet blind hole 41, and the two ends of the glue inlet through hole 32 are respectively threaded to connect two copper pipes. Denoted as the left copper pipe 11.1 and the right copper pipe 11.2, the left part of the left copper pipe 11.1 is plugged into the glue injection pipe 4, and the right part of the right copper pipe 11.2 is connected with the glue-feeding blind hole 41, and the orifice The outer ring surface of the end cover 8 is sequentially opened with an annular sealing ring groove 30, a first binding groove 30.1, a rubber guide groove 33, and a second binding groove 30.2 from left to right. The glue through hole 32 and the glue guide groove 33 have three threading holes 36 evenly distributed in the circumferential direction of the portion adjacent to the right end of the cable hole 24 of the orifice end cover 8, that is, the front cavity 37 of the orifice end cover adjacent to the right end of the cable hole 24 is uniformly distributed in the circumferential direction. A threading hole 36, and the front cavity 37 of the orifice end cover is filled with potting resin 10.

The two ends of the inclusion base pipe 17 are processed into steps 38 respectively matched with the end cap 8 of the hole and the end cap 19 at the bottom of the hole. , the inclusion base pipe 17 is a fixed-diameter seamless steel pipe, aluminum alloy pipe, copper pipe, epoxy resin pipe, PE pipe, or PVC pipe.

The pressure regulating hole 45 is provided with an internal thread section and a top pressure section in sequence. A part of the internal thread section from left to right is an internal thread. The diameter of the threaded section is greater than the diameter of the top pressure section; the outer ring surface of the hole bottom cover 19 is sequentially opened with a circular glue outlet 40, a third binding groove 35.1, a glue guide groove 33, and a fourth binding groove from left to right. Groove 35.2, plugging ring groove 30, glue outlet groove 40 is communicated with the outlet of glue outlet hole 44;

The surface layer of the installation rod 1 is cut from a thin-walled stainless steel pipe, the rod connection sleeve 5 and the body connection sleeve 6 are processed by seamless steel pipes, the hole end cover 8 and the hole bottom end cover 19 are processed by aluminum alloy rods, and the left copper Pipe 11.1, right copper tube 11.2 are all processed with capillary copper tube, and the material of rubber expansion bag 15 is butyl rubber tube, and all the other parts are standard parts.

As shown in Figure 1, when the installation part of the present utility model is assembled, at first the 15-core shielded wire 3 is welded with temperature compensation and zeroing strain rosette 13 and puts in the tail cavity 28 of the orifice end cover 8, the tail cavity 28 The internal potting resin 10 plays the role of sealing and protection. Screw the left copper pipe 11.1 and the orifice end cover 8. Apply sealant or wrap the sealing tape on the thread to avoid glue leakage. The core wire is divided into three strands to form a strained wire group 16 After the two ends are filled with resin glue and hardened, connect the right copper pipe 11.2, the body base pipe 17, the pressure adjusting screw 20, the compression spring 21, the valve ball 22, the hole bottom end cover 19, and weld the strain flower wire group 16 and Four pieces of strain rosettes 18 are installed, and a thin layer of potting resin 10 is applied on the outer layer to protect the measuring rosettes 18. After the potting resin 10 is cured, insert the rubber expansion bag 15, the sealing ring 12, and the iron hoop wire 14 to tighten the sealant The expansion bag 15 is assembled as described above.

The utility model is provided with a glue injection channel including a glue injection pipe 4, a left copper pipe 11.1, a right copper pipe 11.2, an orifice end cover 8, and a hole bottom end cover 19, and is closed by a rubber expansion bag 15. When the glue pressure is lower than When the valve core pressure is set by the pressure regulating screw 20, compression spring 21, and valve ball 22, the rubber expansion bag 15 will swell first, so that the hole of the strain gauge is sealed and centered. Open the gap between the glue injection strain gauge and the hole wall of the measured borehole 47 to complete the glue filling under pressure.

The installation process of the present utility model is, as shown in Fig. 6, 7, for clear illustration, the mark has been simplified:

Before the installation of the utility model, drill the measured drill hole 47 according to the requirements, connect the installation part and the body connecting sleeve 6, insert the rubber injection pipe 4 into the left copper pipe 11.1, tighten the fastening pipe screw 7, and place it in the rod connecting sleeve 5 in turn. Insert the injection tube 4 and the 15-core shielded wire 3, the connecting rod connecting sleeve 5 and the installation rod 1 of each section, and push the installation part to the bottom of the hole.

After the installation part is put in place, the outer end of the hole of the injection pipe 4 can be connected to the glue outlet of the hand-operated glue injection pump to pump the pressure potting glue 46, and the rubber expansion bag 15 will be expanded along the glue injection channel, and then the strain gauge and The gap between the hole walls of the measured drill hole 47, after the glue in the gap is cured, pull the installation rod 1, and the glue injection tube 4, the rod connecting sleeve 5, and the body connecting sleeve 6 can be withdrawn together, and then the strain measurement can be carried out. Measurement.

Compared with the prior art, the zero-position memory pumping inclusion strain gauge provided in this embodiment has the following advantages:

1. Due to the setting of zero-adjustment strain gauges, a single strain gauge can measure multiple strain gauges at the same observation period, which greatly reduces the supporting cost of porous measurement in dynamic pressure testing;

2. The designed inclusion base pipe 17 can be made of epoxy resin pipe, PE pipe, PVC pipe to form a soft inclusion body, or seamless steel pipe and thick-walled aluminum pipe to form a hard inclusion body. The modulus and Poisson's ratio are involved, respectively dealing with hard rock and soft rock, the elastic deformation range of the hole wall is wider, and the measurement accuracy is higher;

3. A closed channel for pump injection type glue injection is designed, and the filling pressure of the installation part can be preset through the pressure regulating component. Shaft, the perfusion cavity is greatly reduced, the installation positioning accuracy is greatly improved, and the reliability and validity of the strain measurement data are improved;

4. The fifteen-core shielded wire 3 and the injection tube 4 are protected in the installation rod 1 during installation, which avoids the scratching of the two by the hole wall of the measured drill hole 47 during installation, and the fixed pipe screw 7 is set to ensure that the injection tube 4 With the reliable exit of the body connecting sleeve 6;

5. The zero-position memory pump injection type cladding strain gauge has popular material selection for parts and components, convenient processing and assembly, and convenient installation and measurement.

The specific embodiments described herein are only examples to illustrate the spirit of the present invention. Those skilled in the technical field to which the utility model belongs can make various modifications or supplements to the described specific embodiments or adopt similar methods to replace them, but they will not deviate from the spirit of the utility model or go beyond the appended claims defined range .

Claims (6)

1. A zero-position memory pumping type cladding strain gauge, which includes a mounting part and a mounting rod (1) for pushing the mounting part, and the mounting part includes a measuring line and an orifice end cover (8) connected in sequence, Inclusion base pipe (17), hole bottom end cap (19), characterized in that both the hole end cap (8) and the hole bottom end cap (19) are provided with a sealing ring (12) and sequentially connected inlet The glue hole, the glue guide hole (34), the annular glue guide groove (33) arranged on the outer surface, covering the rubber expansion bladder (15) with elasticity around the glue guide groove (33), and the two ends of the rubber expansion bladder (15) It is sealed and fixed on the outer surface so that the rubber expansion bag (15) and the rubber guide groove (33) form a sealed expansion chamber, and the sealing ring (12) of the orifice end cover (8) is located on the left side of the rubber expansion bag (15) side, the sealing ring (12) of the hole bottom end cover (19) is located on the right side of the rubber bladder (15), and the glue inlet hole of the orifice end cover (8) is connected to the glue inlet hole of the hole bottom end cover (19). Connected; the hole bottom end cover (19) is provided with a pressure regulating hole (45) connected with the glue guide hole (34), a glue outlet hole (44) connected with the pressure regulating hole (45), and the pressure regulating hole (45) There is a pressure regulating assembly for controlling the connection between the glue outlet hole (44) and the glue guide hole (34). The outlet of the glue outlet hole (44) is located on the outer surface of the end cover (19) at the bottom of the hole Cover the left side of the capsule (15) of the cover (19). 2. The zero-position memory pumping inclusion strain gauge according to claim 1, characterized in that the measuring line includes three groups of four-piece strain rosettes uniformly distributed in the circumferential direction and potted on the outer ring surface of the inclusion base pipe (17) (18) and the temperature compensation and zeroing strain rosettes (13) with the same sensitivity coefficient buried in the tail cavity (28) of the orifice end cover (8), each strain rosette is connected to the fifteen-core shielded wire (3) respectively connection, the fifteen-core shielded wire (3) is pulled out through the first cable hole (24) arranged on the hole end cover (8). 3. The zero-position memory pumping type inclusion strain gauge according to claim 1, characterized in that the installation rod (1) includes a rod connecting sleeve (5), and the left part of the orifice end cover (8) can be The body connecting sleeve (6) of the detachable connection, the inside of the rod connecting sleeve (5) and the inside of the body connecting sleeve (6) are provided with a second cable hole (31) and a hose hole (25), and the body connecting sleeve ( 6) There is also a fixed pipe screw hole (26) that is horizontally split through the rubber hose hole (25) inside, and a fixed pipe screw hole (26) is provided with a rubber injection tube (4) for fixing and plugging into the glue inlet hole. The fixed pipe screw (7), the right end of the body connecting sleeve (6) is provided with an orientation slot (27) for pushing the installation part, and the left part of the orifice end cover (8) is provided with an orientation slot (27) for sliding fit. Pin (9), the directional pin (9) is located on the left side of the blanking ring (12) of the orifice end cap (8). 4. The zero-position memory pumping type inclusion strain gauge according to claim 1, characterized in that, the glue inlet hole of the orifice end cover (8) is a glue inlet through hole (32), and the bottom of the hole is The glue inlet hole of the cover (19) is the glue inlet blind hole (41), and the two ends of the glue inlet through hole (32) are respectively threaded to connect two copper pipes, recorded as the left copper pipe (11.1) and the right copper pipe (11.2), The left part of the left copper pipe (11.1) is plugged into the glue injection pipe (4), the right part of the right copper pipe (11.2) is connected to the glue-injecting blind hole (41), and the orifice end cover (8 ) on the outer ring surface from left to right, there are all ring-shaped blocking ring grooves (30), the first binding groove (30.1), the rubber guide groove (33), the second binding groove (30.2), and the horizontal The guide glue hole (34) communicates with the glue inlet through hole (32) and the glue guide groove (33), and there are three threading holes (36) evenly distributed in the peripheral direction of the portion adjacent to the right end of the cable hole (24) of the orifice end cover (8). 5. The zero-position memory pump-injection inclusion strain gauge according to claim 1, characterized in that, the two ends of the inclusion base pipe (17) are processed to be connected with the orifice end cover (8) and the hole bottom respectively. The step (38) that the end cap (19) cooperates, and the base pipe (17) of the package body are seamless steel pipes or aluminum alloy pipes or copper pipes or epoxy resin pipes or PE pipes or PVC pipes with fixed pipe diameters. 6. The zero-position memory pump-injection inclusion strain gauge according to claim 1, characterized in that the pressure regulating hole (45) is provided with an internal thread section and a top pressure section in sequence, and the internal thread section and the glue outlet hole ( 44) connected, the top pressure section is connected with the glue guide hole (34), and the diameter of the internal thread section is larger than the diameter of the top pressure section; Glue outlet groove (40), third strapping groove (35.1), glue guide groove (33), fourth strapping groove (35.2), sealing ring groove (30), glue outlet groove (40) and glue outlet hole (44 ) is connected to the outlet; the right end of the end cover (19) at the bottom of the hole is a tapered guide head (42).