Tap thread gage grinder

Abstract

The utility model belongs to the technical field of machining, concretely relates to a tap thread groove grinding machine, including the lathe bed, be equipped with the grinding device, workpiece clamping device, grinding wheel dressing device and cooling device on the lathe bed, the grinding device includes the rotary table, the first elevating system being arranged on the rotary table top, the grinding wheel being arranged on the first elevating system, and the first drive mechanism of driving the grinding wheel rotation, the rotary table is connected to the adjusting mechanism, the grinding wheel dressing device includes the second elevating system being arranged on the first elevating system, the translation mechanism being arranged on the second elevating system, the grinding head being arranged on the translation mechanism, and the second drive mechanism of driving the grinding head rotation, the workpiece clamping device includes the moving mechanism, the drag plate and the jig and the tailstock being oppositely arranged on the drag plate top, one end of the jig is connected to the rotating mechanism, the cooling device includes the grinding cooling oil pipe and the correction cooling hose.

Description

Technical Field

[0001] This utility model belongs to the field of mechanical processing technology, specifically relating to a tap thread grinding machine. Background Technology

[0002] A tap is a cutting tool used for machining internal threads. It has a simple structure and is easy to use, operating both manually and on machine tools, and is widely used in production. During the manufacturing process, the grooves on the surface of a tap need to be ground to make them sharp and smooth, thus meeting production requirements.

[0003] In current tap grinding machines, both the tap and the grinding wheel are fixed above the machine tool. The angle between the grinding wheel and the platform is limited, so the angle between the grinding wheel and the tap shank remains constant. However, different tap sizes result in different cutting angles of the grinding wheel on the thread grooves, meaning the angles between the grinding wheel and the tap vary. Therefore, tap grinding machines struggle to process multiple types of taps, requiring the pre-design and manufacture of multiple sets of milling cutters. This increases production costs and adds an extra step. Consequently, existing grinding machines have limited adaptability and poor versatility, making them unsuitable for processing various tap types. (Announcement No. CN210147657) U discloses a tap grinding machine that achieves translation of the main spindle unit and the worktable through three-axis linkage, and allows the main spindle unit to be rotated and adjusted at multiple angles, thus having better versatility. However, it can only adjust the angle of the main spindle unit and cannot grind the shape of the grinding wheel in real time as needed, or dress the grinding wheel. Furthermore, the workpiece is fixed by a fastening wheel and a clamp, which is prone to loosening during the grinding process, thus affecting the production quality. Therefore, it cannot meet the needs of the current machinery industry for multi-variety, high-efficiency and rapid development.

[0004] Therefore, the above-mentioned problems should be considered and solved during the process of machining threads with taps. Utility Model Content

[0005] To address the above problems and solve the aforementioned technical issues, this utility model discloses a tap thread grinding machine, the specific technical solution of which is as follows:

[0006] This utility model provides a tap thread grinding machine, which includes a bed, and a grinding device, a workpiece clamping device, a grinding wheel dressing device and a cooling device are provided above the bed.

[0007] The grinding device includes a rotary table, a first lifting mechanism disposed above the rotary table, a grinding wheel disposed on the first lifting mechanism, and a first driving mechanism for driving the grinding wheel to rotate. The rotary table is connected to an adjustment mechanism.

[0008] The grinding wheel dressing device includes a second lifting mechanism disposed on the first lifting mechanism, a translation mechanism disposed on the second lifting mechanism, a dressing head disposed on the translation mechanism, and a second driving mechanism for driving the dressing head to rotate, wherein the dressing head is disposed above the grinding wheel;

[0009] The workpiece clamping device includes a moving mechanism, a slide, and a clamp and a center disposed opposite to each other above the slide, with one end of the clamp connected to a rotating mechanism;

[0010] The cooling device includes a grinding cooling oil pipe and a dressing cooling hose, which are used to cool the workpiece and the dressing grinding head, respectively.

[0011] A further improvement of this utility model is that: the first lifting mechanism includes a support and a first lifting motor disposed above the support, the output end of the first lifting motor is provided with a first lifting screw, the first lifting screw is provided with a first lifting nut, the first lifting nut is connected to a fixed seat, one side of the support is provided with a first slide rail, the side of the fixed seat is provided with a first slider adapted to the first slide rail, and the grinding wheel is disposed on the fixed seat through a transmission shaft.

[0012] A further improvement of this utility model is that: the first drive mechanism includes a base disposed above the rotary table and a first servo motor slidably disposed on the base, the first servo motor is mounted on the support plate, the output end of the first servo motor is connected to the transmission shaft via a belt, and a tension adjustment rod is provided between the fixed seat and the support plate.

[0013] A further improvement of this utility model is that: the second lifting mechanism includes a grinding head seat fixed to one side of the support, a second lifting motor is provided on the top of the grinding head seat, a second lifting screw is provided at the output end of the second lifting motor, a second lifting nut is provided on the second lifting screw, the second lifting nut is connected to the mounting seat, a second slide rail is provided on one side of the mounting seat, and a second slider adapted to the second slide rail is provided on the side of the grinding head seat.

[0014] A further improvement of this utility model is that: the second drive mechanism includes a mounting plate and a second servo motor and a spindle seat mounted on the mounting plate. The output end of the second servo motor is connected to a shaft in the spindle seat via a gear. The grinding head is disposed at one end of the shaft. The translation mechanism includes a fixed plate mounted on one side of the mounting base, a translation motor and a translation screw. The translation motor is fixed on the fixed plate, and the translation screw is connected to the spindle seat. The top of the spindle seat is provided with a translation track, and the bottom of the fixed plate is provided with a translation slider connected to the translation track.

[0015] A further improvement of this utility model is that: a base plate is provided above the bed, one corner of the rotary table is rotatably connected to the base plate through a rotating shaft, the adjustment mechanism includes an adjustment seat provided on the bed, a spur gear provided in the adjustment seat and a spur tooth adapted to the spur gear, a connecting ear is provided on the outer side of the rotary table, one end of the spur tooth extends out of the adjustment seat and the other end is connected to the connecting ear.

[0016] A further improvement of this utility model is that: the moving mechanism includes a pad plate disposed above the bed, a track seat disposed above the pad plate, a moving motor disposed at one end of the track seat, a moving screw connected to the output end of the moving motor, a moving nut disposed on the moving screw for connecting the slide plate, moving tracks disposed on both sides of the track seat, and a moving slider adapted to the moving tracks disposed at the bottom of the slide plate.

[0017] A further improvement of this utility model is that: the rotating mechanism includes a seat plate fixed above the slide plate, a movable oil cylinder fixed above the seat plate by a bracket, and a gearbox arranged above the seat plate by a needle roller track. A set of bevel gears is provided in the gearbox. The input end of the bevel gears is connected to a rotating motor, and the output end of the bevel gears is connected to the clamp through a rotating shaft. A center seat is provided above the slide plate, and the center is fixed above the center seat.

[0018] A further improvement of this utility model is that: the cooling device includes an oil inlet and an oil outlet, a three-way pipe connected to the oil inlet is provided above the machine bed, one end of the three-way pipe is connected to a grinding cooling oil pipe, and the other end is connected to a correction cooling hose, the grinding cooling oil pipe is positioned facing the workpiece, the correction cooling hose is positioned above the grinding head, and an oil leakage hole is provided on the machine bed, the oil leakage hole is connected to the oil outlet.

[0019] A further improvement of this utility model is that: a protective cover is provided on the outside of the slide, a set of door rails is provided on the outside of the protective cover, a sliding door is provided inside the door rails, one end of the sliding door is connected to an opening and closing cylinder, and the opening and closing cylinder is fixed above the bed by a support frame.

[0020] Compared with the prior art, this utility model can achieve the following technical effects: 1. This utility model has a simple structure, is easy to operate, and is compact. The grinding device is set on a rotary table, and the angle of the grinding wheel can be adjusted by the adjustment mechanism to meet the various angle requirements of the spiral groove, thus achieving the effect of processing taps of various specifications with the same grinding wheel; 2. The moving mechanism in the workpiece clamping device can effectively correct the position of the workpiece in real time according to the actual error of different workpieces, reduce positioning error, and, together with the center, effectively ensure the stability of the workpiece during the grinding process; 3. The grinding wheel dressing device can dress the grinding wheel shape required for different specifications of taps, making the tap grinding machine more applicable; 4. The cooling device can effectively cool the grinding wheel, grinding head and workpiece on the one hand, and flush the parts on the other hand, ensuring the processing quality; 5. This utility model can realize automatic grinding, making the whole process fully automated, which can effectively reduce the workload of operators. Operators only need to stand on the side to supervise. Even if an accident occurs where the grinding wheel suddenly bursts during high-speed rotation, the operator will not be injured, thus improving the safety of operation. Attached Figure Description

[0021] The accompanying drawings, which are included to provide a further understanding of the present invention and constitute a part of this invention, illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain the present invention and do not constitute an undue limitation thereof. In the drawings:

[0022] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0023] Figure 2 This is a schematic diagram of the internal structure of this utility model;

[0024] Figure 3 This is a schematic diagram of the rear structure of this utility model;

[0025] Figure 4 This is a rear view of the present invention;

[0026] Figure 5 This is a schematic diagram showing the connection between the first lifting mechanism and the second lifting mechanism in this utility model;

[0027] Figure 6 This is a schematic diagram of the adjustment mechanism in this utility model;

[0028] Figure 7 This is a schematic diagram of the grinding head holder structure in this utility model;

[0029] Figure 8 This is a schematic diagram of the second drive mechanism in this utility model;

[0030] Figure 9This is a schematic diagram of the slide structure in this utility model;

[0031] Figure 10 This is a schematic diagram of the rotating mechanism in this utility model;

[0032] Figure 11 This is a schematic diagram of the moving mechanism in this utility model;

[0033] Figure 12 This is a schematic diagram of the translation mechanism in this utility model;

[0034] Figure 13 This is a schematic diagram of the protective cover in this utility model;

[0035] Among them, 1-bed, 2-workpiece, 101-rotary table, 102-grinding wheel, 103-support, 104-first lifting motor, 105-first lifting screw, 106-first lifting nut, 107-fixed seat, 108-first slide rail, 109-first slider, 110-drive shaft, 111-base, 112-first servo motor, 113-belt, 114-tension adjusting rod, 115-base plate, 116-rotating shaft 117-Adjusting seat, 118-Spur gear, 119-Spur gear, 120-Connecting ear, 121-Support plate, 201-Slide plate, 202-Clamp, 203-Center, 204-Plate, 205-Railway seat, 206-Moving motor, 207-Moving screw, 208-Moving nut, 209-Moving rail, 210-Moving slider, 211-Seat plate, 212-Bracket, 213-Moving cylinder, 214-Needle roller track 215-Gearbox, 216-Bevel gear, 217-Rotating motor, 218-Shaft, 219-Center seat, 220-Protective cover, 221-Door rail, 222-Sliding door, 223-Opening and closing cylinder, 224-Support frame, 301-Grinding head, 302-Grinding head seat, 303-Second lifting motor, 304-Second lifting screw, 305-Second lifting nut, 306-Mounting base, 307-Second slide rail, 308-The Two sliders, 309-mounting plate, 310-second servo motor, 311-spindle seat, 312-gear, 313-shaft, 314-fixed plate, 315-translation motor, 316-translation screw, 317-translation rail, 318-translation slider, 319-translation nut, 401-grinding cooling oil pipe, 402-correction cooling hose, 403-oil inlet, 404-oil outlet, 405-tee pipe, 406-oil leak hole. Detailed Implementation

[0036] The following will describe in detail the implementation of this utility model with reference to the accompanying drawings and embodiments, so that the implementation of this utility model can be fully understood and carried out based on how technical means are used to solve technical problems and achieve technical effects.

[0037] This embodiment provides a tap thread grinding machine, which includes a bed 1, and a grinding device 100, a workpiece clamping device 200, a grinding wheel dressing device 300 and a cooling device 400 are provided on the bed 1.

[0038] The grinding device includes a rotary table 101, a first lifting mechanism disposed above the rotary table 101, a grinding wheel 102 disposed on the first lifting mechanism, and a first driving mechanism for driving the grinding wheel 102 to rotate. The first lifting mechanism includes a support 103 and a first lifting motor 104 disposed above the support 103. The output end of the first lifting motor 104 is provided with a first lifting screw 105, and a first lifting nut 106 is provided on the first lifting screw 105. The first lifting nut 106 is connected to a fixed seat 107. A first slide rail 108 is provided on one side of the support 103, and a first slider 109 adapted to the first slide rail 108 is provided on the side of the fixed seat 107. The grinding wheel 102 is disposed on the fixed seat 107 via a transmission shaft 110. The first drive mechanism includes a base 111 disposed above the rotary table 101 and a first servo motor 112 slidably disposed on the base 111. The first servo motor 112 is mounted on the support plate 121. The output end of the first servo motor 112 is connected to the drive shaft 110 via a belt 113. When the fixed seat 107 is raised and lowered, in order to maintain the tension of the belt 113, the base 111 and the support plate 121 are slidably connected by a slider and a guide rail. A tensioning device is provided between the fixed seat 107 and the support plate 121. Tighten the adjustment rod 114; the rotary table 101 is connected to the adjustment mechanism, and a base plate 115 is provided above the bed 1. One corner of the rotary table 101 is rotatably connected to the base plate 115 through a rotary shaft 116. The adjustment mechanism includes an adjustment seat 117 provided on the bed 1, a spur gear 118 provided in the adjustment seat 117, and a spur gear 119 adapted to the spur gear 118. A connecting ear 120 is provided on the outer side of the rotary table 101. One end of the spur gear 119 extends out of the adjustment seat 117, and the other end is connected to the connecting ear 120.

[0039] The workpiece clamping device includes a moving mechanism, a slide 201, and a clamp 202 and a center 203 disposed opposite to each other above the slide 201. The moving mechanism includes a pad 204 disposed above the bed 1. A track seat 205 is provided above the pad 204. A moving motor 206 is provided at one end of the track seat 205. The output end of the moving motor 206 is connected to a moving screw 207. A moving nut 208 connected to the slide 201 is provided on the moving screw 207. Moving tracks 209 are provided on both sides of the track seat 205. A moving slider 210 adapted to the moving track 209 is provided at the bottom of the slide 201. One end of the clamp 202 is connected to a rotating mechanism. The rotating mechanism includes a base plate 211 fixed above the slide plate 201, a movable hydraulic cylinder 213 fixed above the base plate 211 by a bracket 212, and a gearbox 215 disposed above the base plate 211 via a needle roller track 214. The gearbox 215 contains a set of bevel gears 216. The input end of the bevel gears 216 is connected to a rotating motor 217, and the output end of the bevel gears 216 is connected to the [unclear - likely a specific component or mechanism] via a rotating shaft 218. The fixture 202 has a center seat 219 above the slide 201, and the center 203 is fixed above the center seat 219. The slide 201 is also provided with a protective cover 220. A set of door rails 221 is provided on the outside of the protective cover 220. A sliding door 222 is provided inside the door rails 221. One end of the sliding door 222 is connected to an opening and closing cylinder 223. The opening and closing cylinder 223 is fixed above the bed 1 by a support frame 224. The protective cover can prevent oil from splashing during operation.

[0040] The grinding wheel dressing device includes a second lifting mechanism mounted on the first lifting mechanism, a translation mechanism mounted on the second lifting mechanism, a dressing head 301 mounted on the translation mechanism, and a second driving mechanism for driving the dressing head 301 to rotate. The second lifting mechanism includes a grinding head seat 302 fixed to one side of the fixed base 107. A second lifting motor 303 is provided on the top of the grinding head seat 302. A second lifting screw 304 is provided at the output end of the second lifting motor 303. A second lifting nut 305 is provided on the second lifting screw 304. The second lifting nut 305 is connected to a mounting base 306. A second slide rail 307 is provided on one side of the mounting base 306. A second slider 307 adapted to the second slide rail 307 is provided on the side of the grinding head seat 302. 08. The second drive mechanism includes a mounting plate 309 and a second servo motor 310 and a spindle seat 311 mounted on the mounting plate 309. The output end of the second servo motor 310 is connected to a shaft 313 inside the spindle seat 311 via a gear 312. The grinding head 301 is disposed at one end of the shaft 313. The translation mechanism includes a fixed plate 314 mounted on one side of the mounting base 306, a translation motor 315, and a translation screw 316. The translation motor 315 is fixed on the fixed plate 314. The translation screw 315 is connected to the spindle seat 311 via a translation nut 319. The top of the spindle seat 311 is provided with a translation rail 317, and the bottom of the fixed plate 314 is provided with a translation slider 318 connected to the translation rail 317. The grinding head 301 is disposed above the grinding wheel 102.

[0041] The cooling device includes a grinding cooling oil pipe 401 and a correction cooling hose 402, which are used to cool the workpiece 2 and the grinding head 301, respectively. The cooling device 400 also includes an oil inlet 403 and an oil outlet 404. A three-way pipe 405 communicating with the oil inlet 403 is provided above the bed 1. One end of the three-way pipe 405 is connected to the grinding cooling oil pipe 401, and the other end is connected to the correction cooling hose 402. The grinding cooling oil pipe 401 is positioned directly opposite the workpiece 2, and the correction cooling hose 402 is positioned above the grinding head 301. An oil leakage hole 406 is provided on the bed 1, and the oil leakage hole 406 communicates with the oil outlet 404.

[0042] This embodiment provides a tap thread grinding machine, the working principle of which is as follows: a first servo motor 112 drives the grinding wheel 102 to rotate, a second servo motor 310 drives the grinding head 302 to rotate, a first lifting motor 104 drives the grinding wheel 102 to rise and fall, a second lifting motor 303 drives the grinding head 302 to rise and fall, a translation motor 315 drives the grinding head 302 to move back and forth, and a movement motor 206 drives the slide plate 201 to move. When it is necessary to cut the tap shank, the workpiece 2 to be cut is first installed on the fixture 202, and the movement is started. The hydraulic cylinder 213 causes the workpiece 2 to press tightly against the center 203, thus clamping the workpiece between the fixture 202 and the center 203. The moving mechanism is activated, causing the slide plate 201 to move, thereby moving the workpiece 2 below the grinding wheel 102. According to the required process angle of the spiral tap, the angle of the grinding wheel 102 is adjusted via the adjusting mechanism (by manually pulling the spur gear 119, which drives the rotary table 101 to rotate, thus adjusting the angle of the grinding wheel 102). Simultaneously, the first lifting mechanism is activated, via the first lifting motor 10... 4. The first lifting screw 105 drives the fixed seat 107 to move, thereby adjusting the height of the grinding wheel 102. The rotating motor 217 is started, which drives the rotating shaft 218 to rotate through the bevel gear 216, thereby driving the workpiece 2 to rotate. Then, the first servo motor 112 is started, and the grinding wheel 102 rotates to grind the workpiece 2. When dressing the grinding wheel 102, the grinding wheel dressing device is started. The second lifting motor 303 and the second lifting screw 304 drive the mounting seat 306 to move, thereby driving the grinding head 302 to move up and down, and through translation... The motor 315 and the translation screw 316 drive the grinding head to move left and right, thereby dressing the grinding wheel 102. The cooling device is provided, and the cooling oil is connected to the grinding cooling hose 401 and the dressing cooling hose 402 through the three-way pipe 405 respectively. The grinding cooling hose 401 can be set with a branch pipe to be aligned with the workpiece 2 to cool the workpiece 2. The dressing cooling hose 402 is set directly above the grinding head 302, which can cool the grinding head 302 on the one hand, and wash the debris adhering to the surface of the grinding wheel 102 on the other hand.

[0043] The foregoing description illustrates and describes several preferred embodiments of the present invention. However, as previously stated, it should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the inventive concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A tap thread grinding machine, comprising a bed, characterized in that: The bed is equipped with a grinding device, a workpiece clamping device, a grinding wheel dressing device, and a cooling device. The grinding device includes a rotary table, a first lifting mechanism disposed above the rotary table, a grinding wheel disposed on the first lifting mechanism, and a first driving mechanism for driving the grinding wheel to rotate. The rotary table is connected to an adjustment mechanism. The grinding wheel dressing device includes a second lifting mechanism disposed on the first lifting mechanism, a translation mechanism disposed on the second lifting mechanism, a dressing head disposed on the translation mechanism, and a second driving mechanism for driving the dressing head to rotate, wherein the dressing head is disposed above the grinding wheel; The workpiece clamping device includes a moving mechanism, a slide, and a clamp and a center disposed opposite to each other above the slide, with one end of the clamp connected to a rotating mechanism; The cooling device includes a grinding cooling oil pipe and a dressing cooling hose, which are used to cool the workpiece and the dressing grinding head, respectively.

2. The tap thread grinding machine according to claim 1, characterized in that: The first lifting mechanism includes a support and a first lifting motor disposed above the support. The output end of the first lifting motor is provided with a first lifting screw, and the first lifting screw is provided with a first lifting nut. The first lifting nut is connected to a fixed seat. One side of the support is provided with a first slide rail, and the side of the fixed seat is provided with a first slider adapted to the first slide rail. The grinding wheel is disposed on the fixed seat through a transmission shaft.

3. The tap thread grinding machine according to claim 2, characterized in that: The first drive mechanism includes a base disposed above the rotary table and a first servo motor slidably disposed on the base. The first servo motor is mounted on a support plate, and the output end of the first servo motor is connected to the drive shaft via a belt. A tension adjustment rod is provided between the fixed base and the support plate.

4. A tap thread grinding machine according to claim 2, characterized in that: The second lifting mechanism includes a grinding head seat fixed to one side of the support. A second lifting motor is provided on the top of the grinding head seat. A second lifting screw is provided at the output end of the second lifting motor. A second lifting nut is provided on the second lifting screw. The second lifting nut is connected to a mounting base. A second slide rail is provided on one side of the mounting base. A second slider that is adapted to the second slide rail is provided on the side of the grinding head seat.

5. A tap thread grinding machine according to claim 4, characterized in that: The second drive mechanism includes a mounting plate and a second servo motor and a spindle seat mounted on the mounting plate. The output end of the second servo motor is connected to a shaft inside the spindle seat via a gear. The grinding head is disposed at one end of the shaft. The translation mechanism includes a fixed plate mounted on one side of the mounting base, a translation motor, and a translation screw. The translation motor is fixed on the fixed plate, and the translation screw is connected to the spindle seat. The top of the spindle seat is provided with a translation rail, and the bottom of the fixed plate is provided with a translation slider connected to the translation rail.

6. The tap thread grinding machine according to claim 1, characterized in that: A base plate is provided above the bed. One corner of the rotary table is rotatably connected to the base plate via a rotating shaft. The adjustment mechanism includes an adjustment seat provided on the bed, a spur gear provided in the adjustment seat, and a spur tooth adapted to the spur gear. A connecting ear is provided on the outer side of the rotary table. One end of the spur tooth extends out of the adjustment seat, and the other end is connected to the connecting ear.

7. A tap thread grinding machine according to claim 1, characterized in that: The moving mechanism includes a pad mounted above the bed, a track seat above the pad, a moving motor at one end of the track seat, a moving screw connected to the output end of the moving motor, a moving nut on the moving screw that connects to the slide, moving tracks on both sides of the track seat, and a moving slider adapted to the moving tracks at the bottom of the slide.

8. The tap thread grinding machine according to claim 1, characterized in that: The rotating mechanism includes a seat plate fixed above the slide, a movable hydraulic cylinder fixed above the seat plate by a bracket, and a gearbox set above the seat plate by a needle roller track. The gearbox contains a set of bevel gears. The input end of the bevel gears is connected to a rotating motor, and the output end of the bevel gears is connected to the clamp via a rotating shaft. A center seat is provided above the slide, and the center is fixed above the center seat.

9. A tap thread grinding machine according to claim 1, characterized in that: The cooling device includes an oil inlet and an oil outlet. A three-way pipe connected to the oil inlet is provided above the machine bed. One end of the three-way pipe is connected to a grinding cooling oil pipe, and the other end is connected to a correction cooling hose. The grinding cooling oil pipe is positioned directly above the workpiece, and the correction cooling hose is positioned above the grinding head. An oil leakage hole is provided on the machine bed, and the oil leakage hole is connected to the oil outlet.

10. A tap thread grinding machine according to claim 1, characterized in that: The slide is equipped with a protective cover, and a set of door rails is provided on the outside of the protective cover. A sliding door is provided inside the door rails. One end of the sliding door is connected to an opening and closing cylinder, and the opening and closing cylinder is fixed above the bed by a support frame.

Images