Welding tool for cylinder machining

Abstract

The utility model relates to the technical field of cylinder ore washer machining assistive devices, and discloses a welding tool for cylinder machining, which comprises a plurality of ribs, a positioning unit is arranged among the ribs, the positioning unit comprises a plurality of U-shaped plates, the U-shaped plates are respectively sleeved on the outer sides of the ribs, and the U-shaped plates are arranged on the outer sides of the ribs. And the surface of the U-shaped plate is in threaded connection with a first bolt. According to the welding tool for cylinder machining, through cooperation of ribs and positioning units, a motor runs and drives a lead screw to rotate, a threaded cylinder is driven when the lead screw rotates, the threaded cylinder moves on the outer wall of the lead screw, and in the process, through transmission of inclined rods, a plurality of square cylinders synchronously stretch out in the direction away from the lead screw; and at the moment, the control switch is switched off, the multiple ribs can be annularly and equidistantly distributed and positioned on the inner wall of the cylinder, and in the welding process, the ribs do not need to be calibrated one by one, and hand-held auxiliary positioning is also not needed.

Description

Technical Field

[0001] The utility model relates to the technical field of processing auxiliary tools for cylindrical ore washing machines, in particular to a welding tooling for cylindrical processing. Background Technique

[0002] The small cylindrical ore washing machine is a device designed for the ore washing needs of small and medium-sized mines. Its core structure is a rotating cylinder, which removes the soil and impurities adhering to the ore surface by combining mechanical friction and water flow flushing. It has the characteristics of compact volume, flexible operation, and low energy consumption, and is suitable for small mines, sand and gravel yards or laboratories and other scenarios.

[0003] As a key device in the field of mine washing and dressing, the welding process of the small cylindrical ore washing machine directly determines the stability and service life of the equipment. The convex pieces provided inside the cylinder of the small cylindrical ore washing machine are usually called rib strips in the professional field. In the cylindrical ore washing machine, the rib strips are longitudinal convex structures fixed on the inner wall of the cylinder, and their function is to stir the materials through the mechanical force generated by rotation, so that the ore and the water flow are fully contacted to enhance the scrubbing effect.

[0004] In the process of welding and fixing multiple rib strips on the inner wall of the cylinder, in order to ensure the stability of the subsequent rolling of the cylinder, it is necessary to distribute and weld multiple rib strips equidistantly in a ring on the inner wall of the cylinder as much as possible. At present, the manufacturer lacks a positioning tooling that can distribute and weld multiple rib strips equidistantly in a ring on the inner wall of the cylinder. Usually, a laser calibrator needs to be used for positioning. Although this operation can weld multiple rib strips equidistantly in a ring on the inner wall of the cylinder, in this process, each rib strip needs to be calibrated one by one, and a hand-held positioning operation is also required outside the rib strip during welding, which is rather troublesome and not conducive to the efficient development of welding. Content of the Utility Model

[0005] The purpose of the utility model is to provide a welding tooling for cylindrical processing, which can distribute and position multiple rib strips equidistantly in a ring on the inner wall of the cylinder. During the welding process, it is not necessary to calibrate each rib strip one by one, nor is it necessary to use hand-held auxiliary positioning, which is conducive to the efficient development of the cylindrical processing and welding operation, so as to solve the problems put forward in the above background technique.

[0006] To achieve the above object, the present utility model provides the following technical solutions: A welding tooling for cylinder processing, comprising: a plurality of rib strips, a positioning unit is provided between the plurality of rib strips, and the positioning unit includes: a plurality of U-shaped plates, the plurality of U-shaped plates are respectively sleeved on the outer sides of the plurality of rib strips, a first bolt is threadedly connected to the surface of the U-shaped plate, the first bolt penetrates through the U-shaped plate and abuts against the rib strip, a square tube is connected to the surface of the U-shaped plate, a box body is sleeved on the outer wall of the square tube, a circular plate is fixedly connected to the front end of the box body, a lead screw is rotatably connected to the inner wall of the circular plate, a threaded cylinder is threadedly connected to the outer wall of the lead screw, a plurality of inclined rods are hinged to the outer wall of the threaded cylinder, and the other end of the inclined rod is hinged to the square tube, a motor is fixedly connected to the front surface of the circular plate, an output shaft of the motor is fixedly connected to the lead screw, a power cord is electrically connected to the front side of the motor, a control switch is installed on the line of the power cord, the control switch is fixedly connected to the circular plate, and handles are fixedly connected to both sides of the front surface of the circular plate.

[0007] Preferably, a spirit level is fixedly connected above the front surface of the circular plate.

[0008] Preferably, a support unit is provided at the end of the square tube facing the U-shaped plate, and the support unit includes: a square rod, a part of the square rod is located inside the square tube, the end of the square rod away from the square tube is connected to the U-shaped plate, a second bolt is threadedly connected to the outer wall of the square tube, the second bolt penetrates through the square tube and abuts against the square rod, and a first scale is provided on the outer wall of the square rod.

[0009] Preferably, the square rod is connected to the U-shaped plate through a connection unit, and the connection unit includes: a circular shell, the circular shell is fixedly connected to the end of the square rod away from the square tube, a worm gear is provided inside the circular shell, a cylinder is fixedly connected to the inner wall of the worm gear, the cylinder is rotatably connected to the circular shell through a ball bearing, the end of the cylinder is fixedly connected to the U-shaped plate, a worm is meshed with the outer wall of the worm gear, the worm is rotatably connected to the circular shell through a ball bearing, and a knob is fixedly sleeved on the outer wall end of the worm.

[0010] Preferably, a pointer is fixedly connected to one side of the surface of the circular shell, and a second scale is provided on the surface of the U-shaped plate facing the circular shell.

[0011] Preferably, the square tube penetrates through the box body through an auxiliary unit, and the auxiliary unit includes: a T-shaped tube, the T-shaped tube is sleeved on the outer wall of the square tube, the T-shaped tube is connected to the box body through a third bolt, a plurality of balls are slidably clamped in the inner wall of the T-shaped tube, and the balls are attached to the outer wall of the square tube.

[0012] Compared with the prior art, the beneficial effects of the present utility model are: This welding tooling for cylinder processing has the following advantages compared with the traditional technology:

[0013] Through the cooperation between the ribs and the positioning unit, the user first places the multiple ribs to be welded on the inner wall of the cylinder inside the multiple U-shaped plates respectively. During the process of placing the ribs one by one, the user turns the first bolt clockwise to press and position the ribs. Then, the user holds the handle and places the entire tooling into the central position inside the cylinder. After connecting the power cord to an external power supply device, the control switch is closed, the motor runs and drives the screw rod to rotate. When the screw rod rotates, it drives the threaded cylinder, causing the threaded cylinder to move on the outer wall of the screw rod. During this process, through the transmission of the inclined rod, the multiple square cylinders synchronously extend away from the screw rod, so that the multiple ribs are evenly and equidistantly attached to and pressed against the inner wall of the cylinder. At this time, the control switch is disconnected, and the multiple ribs can be evenly and equidistantly distributed and positioned in a circular shape on the inner wall of the cylinder. During the welding process, there is no need to calibrate each rib one by one, nor is it necessary to manually hold for auxiliary positioning, which is beneficial to the efficient development of the cylinder processing and welding operations.

[0014] Through the cooperation between the ribs, the positioning unit and the supporting unit, if during the process of the driving motor driving the multiple ribs to extend towards the inner wall of the cylinder, the maximum extension stroke cannot make the ribs fit and press tightly against the inner wall of the cylinder, the operator can, before the driving motor extends the multiple ribs, turn the second bolt counterclockwise to pull out a part of the square rod from the inside of the square cylinder. During this process, the operator needs to observe the distance between the first scale on the outer wall of the square rod and the end of the square cylinder to ensure that the values of the first scale on the outer walls of the multiple square rods at the end of the square cylinder are the same. Then, turn the second bolt clockwise to press it tightly against the square rod. In this way, the maximum length of the multiple ribs extending outwards can be increased, so as to adapt to the requirements of welding ribs for large-diameter cylinders, and the scope of application is wider.

[0015] Through the cooperation between the ribs, the positioning unit, the supporting unit and the connecting unit, the operator can apply force to the knob to make the worm rotate. During the rotation process, the worm meshes and drives the worm wheel, and then drives the worm wheel, the cylinder, the U-shaped plate and the ribs to adjust the angle. In this way, it is convenient to control the angle orientation of the ribs after being welded on the inner wall of the cylinder to adapt to the requirements of different welding processes.

[0016] Through the cooperation between the ribs, the positioning unit and the auxiliary unit, during the process of the square cylinder extending out of or retracting into the box body, since the ball can roll, the friction between the square cylinder and the penetration surface of the box body can be greatly reduced, so that the square cylinder can smoothly extend and retract, improving the smoothness during the use of the tooling. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Combined with the drawings and referring to the following specific embodiments, the above and other features, advantages and aspects of the various embodiments of the present disclosure will become more obvious. Throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic, and the original parts and elements are not necessarily drawn to scale.

[0018] Figure 1 This is a schematic structural diagram of the present utility model;

[0019] Figure 2 is Figure 1 a partial top view sectional view;

[0020] Figure 3 is Figure 2 an enlarged view of part A in [Figure number];

[0021] Figure 4 is Figure 2 an enlarged view of part B in [Figure number];

[0022] Figure 5 is Figure 1 a schematic diagram of the connection structure at the square tube, square rod and U-shaped plate in [Figure number];

[0023] Figure 6 is Figure 5 a partial top view sectional view of [Figure number];

[0024] Figure 7 is Figure 6 a side view of the overall structure;

[0025] Figure 8 is Figure 5 a side view sectional view of the square tube and square rod in [Figure number];

[0026] Figure 9 is Figure 6 a top view of the overall structure of the worm in [Figure number].

[0027] In the figure: 1, rib; 2, U-shaped plate; 3, first bolt; 4, square tube; 5, box body; 6, round plate; 7, lead screw; 8, threaded barrel; 9, inclined rod; 10, motor; 11, power cord; 12, control switch; 13, handle; 14, spirit level; 15, square rod; 16, second bolt; 17, first scale; 18, round shell; 19, worm gear; 20, cylinder; 21, worm; 22, knob; 23, pointer; 24, second scale; 25, T-shaped barrel; 26, third bolt; 27, ball. Specific embodiments

[0028] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0029] Please refer to Figures 1 - 9, the present utility model provides a technical solution: a welding tooling for cylinder processing, comprising: a plurality of rib strips 1, a positioning unit is arranged between the plurality of rib strips 1, the positioning unit includes: a plurality of U-shaped plates 2, the plurality of U-shaped plates 2 are respectively sleeved outside the plurality of rib strips 1, a first bolt 3 is threadedly connected to the surface of the U-shaped plate 2, the first bolt 3 passes through the U-shaped plate 2 and abuts against the rib strip 1, a square tube 4 is connected to the surface of the U-shaped plate 2, a box body 5 is sleeved on the outer wall of the square tube 4, a circular plate 6 is fixedly connected to the front end of the box body 5, a lead screw 7 is rotatably connected to the inner wall of the circular plate 6, a threaded cylinder 8 is threadedly connected to the outer wall of the lead screw 7, a plurality of inclined rods 9 are hinged to the outer wall of the threaded cylinder 8, the other end of the inclined rod 9 is hinged to the square tube 4, a motor 10 is fixedly connected to the front surface of the circular plate 6, the output shaft of the motor 10 is fixedly connected to the lead screw 7, a power cord 11 is electrically connected to the front side of the motor 10, a control switch 12 is installed on the line of the power cord 11, the control switch 12 is fixedly connected to the circular plate 6, and handles 13 are fixedly connected to both sides of the front surface of the circular plate 6.

[0030] In the specific implementation process, it is particularly worth noting that the rib strip 1 is a convex structure provided inside the cylinder of a small cylinder ore washing machine, which is usually called a "rib strip" in the professional field. In the cylinder ore washing machine, it is a longitudinal convex structure fixed on the inner wall of the cylinder. Its function is to stir the material through the mechanical force generated by rotation, so that the ore is in full contact with the water flow and enhance the scrubbing effect. The lead screw 7 is rotatably connected to the box body 5 through a ball bearing. The casing of the motor 10 is fixedly connected to the circular plate 6. The motor 10 is a servo motor, and the forward and reverse rotation and the rotation speed of the output shaft can be adjusted. The model of the motor 10 is not limited, as long as it meets the requirements of normal use. After the power cord 11 is connected to an external power supply device, the operator can control the start, stop, forward and reverse rotation of the motor 10 by manipulating the closing or opening of the control switch 12. The setting of the handle 13 facilitates the operator to apply force to the whole tooling to pick it up and move it.

[0031] Furthermore, a spirit level 14 is fixedly connected above the front surface of the circular plate 6.

[0032] In the specific implementation process, it is particularly worth noting that the spirit level 14, also known as the bubble level, spirit level vial, or bubble, is a precision instrument component used to detect whether the surface of an object is horizontal or vertical and to measure small inclination angles. The spirit level mainly consists of a housing, a liquid, and a bubble. The spirit level uses the surface tension of the liquid and the action of gravity to indicate the horizontal or vertical state. When the spirit level is placed on a horizontal surface, the liquid is in a balanced state under the action of gravity, and the bubble stays at the preset reference position (usually the center scale) on the housing under the action of buoyancy and surface tension inside the liquid. If the surface is inclined, the liquid will flow along the inclined direction under the action of gravity, causing the position of the bubble to shift. The shift direction is opposite to the inclined direction, and the shift distance is proportional to the inclination angle. By observing the shift of the bubble relative to the reference position, the user can determine the inclination degree and direction of the object surface. The operator can fine-tune the position of the circular plate 6 by observing the spirit level 14, facilitating the subsequent uniform distribution and positioning of multiple ribs 1 on the inner wall of the cylinder.

[0033] Furthermore, a support unit is provided at the end of the square tube 4 close to the U-shaped plate 2. The support unit includes: a square rod 15, a part of the square rod 15 is located inside the square tube 4, the end of the square rod 15 away from the square tube 4 is connected to the U-shaped plate 2, a second bolt 16 is threadedly connected to the outer wall of the square tube 4, the second bolt 16 passes through the square tube 4 and abuts against the square rod 15, and a first scale 17 is provided on the outer wall of the square rod 15.

[0034] In the specific implementation process, it is particularly worth noting that the outer wall of the square rod 15 and the inner wall of the square tube 4 are in clearance fit. Clearance fit means a fit with a clearance (including a minimum clearance equal to zero). Rotate the second bolt 16 counterclockwise to pull out a part of the square rod 15 from inside the square tube 4. During this process, the operator needs to observe the distance between the first scale 17 on the outer wall of the square rod 15 and the end of the square tube 4 to ensure that the values of the first scales 17 on the outer walls of multiple square rods 15 at the end of the square tube 4 are the same. Then, rotate the second bolt 16 clockwise to make it abut against the square rod 15. In this way, the maximum length of multiple ribs 1 extending outward can be increased.

[0035] Furthermore, the square rod 15 is connected to the U-shaped plate 2 through a connection unit. The connection unit includes: a circular shell 18, the circular shell 18 is fixedly connected to the end of the square rod 15 away from the square tube 4, a worm gear 19 is provided inside the circular shell 18, a cylinder 20 is fixedly connected to the inner wall of the worm gear 19, the cylinder 20 is rotationally connected to the circular shell 18 through a ball bearing, the end of the cylinder 20 is fixedly connected to the U-shaped plate 2, a worm 21 is meshed with the outer wall of the worm gear 19, the worm 21 is rotationally connected to the circular shell 18 through a ball bearing, and a knob 22 is fixedly sleeved on the outer wall end of the worm 21.

[0036] In the specific implementation process, it is particularly worth noting that the surface of the circular shell 18 fits against the surface of the U-shaped plate 2. When the knob 22 is rotated, the circular shell 18 will not affect the rotation of the U-shaped plate 2. Apply force to the knob 22 to rotate the worm 21. During the rotation process, the worm 21 meshes with the worm gear 19 for transmission, thereby driving the worm gear 19, the cylinder 20, the U-shaped plate 2, and the rib 1 to adjust the angle. In this way, it is convenient to control the angle orientation of the rib 1 after being welded to the inner wall of the cylinder to meet the requirements of different welding processes.

[0037] Furthermore, a pointer 23 is fixedly connected to one side of the surface of the circular shell 18, and a second scale 24 is provided on the surface of the U-shaped plate 2 facing the circular shell 18.

[0038] In the specific implementation process, it is particularly worth noting that when the knob 22 is rotated to adjust the angle of the rib 1, the operator can visually judge the angle change of the rib 1 after adjustment by observing the angle value pointed by the pointer 23 to the second scale 24, which is convenient for precise control.

[0039] Furthermore, the square tube 4 passes through the box body 5 through the auxiliary unit. The auxiliary unit includes: a T-shaped tube 25, the T-shaped tube 25 is sleeved on the outer wall of the square tube 4, the T-shaped tube 25 is connected to the box body 5 through a third bolt 26, and a plurality of balls 27 are slidably clamped inside the inner wall of the T-shaped tube 25, and the balls 27 are in contact with the outer wall of the square tube 4.

[0040] In the specific implementation process, it is particularly worth noting that the ball 27 is composed of a groove seat and a round bead. The round bead is slidably clamped inside the groove seat and can roll. Specifically, the round bead is in contact with the square tube 4, and the groove seat is fixedly connected to the inner wall of the T-shaped tube 25. During the process of the square tube 4 extending out of the box body 5 or retracting into the box body 5, since the ball 27 can roll, the friction between the square tube 4 and the penetration surface of the box body 5 can be greatly reduced.

[0041] Working principle:

[0042] Positioning operation for multiple ribs:

[0043] First, the user places multiple ribs 1 to be welded on the inner wall of the cylinder into the interiors of multiple U-shaped plates 2 respectively. During the process of placing the ribs 1 one by one, the user rotates the first bolt 3 clockwise to tightly press and position the ribs 1. Then, the user holds the handle 13 and places the entire tooling into the central position inside the cylinder. After connecting the power cord 11 to an external power supply device, the user closes the control switch 12. The motor 10 operates and drives the lead screw 7 to rotate. When the lead screw 7 rotates, it drives the threaded barrel 8, causing the threaded barrel 8 to move on the outer wall of the lead screw 7. During this process, through the transmission of the inclined rod 9, multiple square barrels 4 synchronously extend away from the lead screw 7, so that multiple ribs 1 are evenly and equidistantly attached to and tightly pressed against the inner wall of the cylinder. At this time, the control switch 12 is disconnected, and then the positioning of multiple ribs 1 in an annular and equidistant distribution on the inner wall of the cylinder can be completed. During the welding process, there is no need to calibrate each rib 1 one by one, nor is it necessary to manually hold for auxiliary positioning, which is beneficial to the efficient development of the cylinder processing and welding operations;

[0044] Adjustment of the extended length of multiple ribs:

[0045] If during the process of the driving motor 10 driving multiple ribs 1 to extend towards the inner wall of the cylinder, the maximum extension stroke cannot make the ribs 1 fit and tightly press against the inner wall of the cylinder, the operator can, before the driving motor 10 extends multiple ribs 1, rotate the second bolt 16 counterclockwise and pull out a part of the square rod 15 from the interior of the square barrel 4. During this process, the operator needs to observe the distance between the first scale 17 on the outer wall of the square rod 15 and the end of the square barrel 4 to ensure that the values of the first scale 17 on the outer walls of multiple square rods 15 at the end of the square barrel 4 are the same. Then, rotate the second bolt 16 clockwise to tightly press it against the square rod 15. In this way, the maximum length of multiple ribs 1 extending outward can be increased, so as to adapt to the requirements of welding ribs 1 on large-diameter cylinders, and the applicable range is wider;

[0046] Adjustment of the angular orientation of the ribs on the inner wall of the cylinder:

[0047] The operator can apply force to the knob 22 to rotate the worm 21. During the rotation process, the worm 21 meshes with and drives the worm gear 19, thereby driving the worm gear 19, the cylinder 20, the U-shaped plate 2, and the rib 1 to perform angular adjustment. In this way, it is convenient to control the angular orientation of the rib 1 after being welded on the inner wall of the cylinder to adapt to the requirements of different welding processes;

[0048] Final operation:

[0049] After multiple ribs 1 are annularly and equidistantly distributed and positioned on the inner wall of the cylinder, the operator spot-welds the ribs 1 to the inner wall of the cylinder. Then, the operator rotates the first bolt 3 counterclockwise to separate it from the rib 1. At this time, the driving motor 10 is activated to rotate the output shaft and the lead screw 7 in the reverse direction, and multiple square barrels 4 partially retract into the box body 5. Subsequently, the entire tooling can be taken out from the cylinder to facilitate the positioning operation of the next batch of multiple ribs 1.

[0050] Although the embodiments of the present utility model have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle and spirit of the present utility model. The scope of the present utility model is defined by the appended claims and their equivalents.

Claims

1. Welding tooling for cylinder processing, comprising: Multiple ribs (1), characterized in that: a positioning unit is provided between the multiple ribs (1), and the positioning unit includes: multiple U-shaped plates (2), the multiple U-shaped plates (2) are respectively sleeved on the outer sides of the multiple ribs (1), a first bolt (3) is threadedly connected to the surface of the U-shaped plate (2), the first bolt (3) penetrates through the U-shaped plate (2) and abuts against the rib (1), a square tube (4) is connected to the surface of the U-shaped plate (2), a box body (5) is sleeved on the outer wall of the square tube (4), a circular plate (6) is fixedly connected to the front end of the box body (5), a lead screw (7) is rotatably connected to the inner wall of the circular plate (6), a threaded cylinder (8) is threadedly connected to the outer wall of the lead screw (7), a plurality of inclined rods (9) are hinged to the outer wall of the threaded cylinder (8), the other end of the inclined rod (9) is hinged to the square tube (4), a motor (10) is fixedly connected to the front surface of the circular plate (6), the output shaft of the motor (10) is fixedly connected to the lead screw (7), a power cord (11) is electrically connected to the front side of the motor (10), a control switch (12) is installed on the line of the power cord (11), the control switch (12) is fixedly connected to the circular plate (6), and handles (13) are fixedly connected to both sides of the front surface of the circular plate (6).

2. The welding tooling for cylinder machining according to claim 1, wherein: A spirit level (14) is fixedly connected above the front surface of the circular plate (6).

3. The welding tooling for cylinder processing according to claim 1, characterized in that: A support unit is provided at the end of the square tube (4) close to the U-shaped plate (2), and the support unit includes: a square rod (15), a part of the square rod (15) is located inside the square tube (4), the end of the square rod (15) away from the square tube (4) is connected to the U-shaped plate (2), a second bolt (16) is threadedly connected to the outer wall of the square tube (4), the second bolt (16) penetrates through the square tube (4) and abuts against the square rod (15), and a first scale (17) is provided on the outer wall of the square rod (15).

4. The welding tooling for cylinder processing according to claim 3, characterized in that: The square rod (15) is connected to the U-shaped plate (2) through a connection unit, and the connection unit includes: a circular shell (18), the circular shell (18) is fixedly connected to the end of the square rod (15) away from the square tube (4), a worm gear (19) is provided inside the circular shell (18), a cylinder (20) is fixedly connected to the inner wall of the worm gear (19), the cylinder (20) is rotatably connected to the circular shell (18) through a ball bearing, the end of the cylinder (20) is fixedly connected to the U-shaped plate (2), a worm (21) is meshed with the outer wall of the worm gear (19), the worm (21) is rotatably connected to the circular shell (18) through a ball bearing, and a knob (22) is fixedly sleeved on the outer wall end of the worm (21).

5. The welding tooling for cylinder processing according to claim 4, characterized in that: A pointer (23) is fixedly connected to one side of the surface of the circular shell (18), and a second scale (24) is provided on the surface of the U-shaped plate (2) close to the circular shell (18).

6. The welding tooling for cylinder machining according to claim 1, characterized in that: The square cylinder (4) penetrates through the box body (5) via an auxiliary unit, and the auxiliary unit includes: a T-shaped cylinder (25), the T-shaped cylinder (25) is sleeved on the outer wall of the square cylinder (4), the T-shaped cylinder (25) is connected to the box body (5) by a third bolt (26), and a plurality of ball bearings (27) are slidably clamped on the inner wall of the T-shaped cylinder (25), and the ball bearings (27) are in fit with the outer wall of the square cylinder (4).

Images