TWI551403B - A ratchet wrench with a dustproof structure - Google Patents

Description

Ratchet wrench with dustproof structure

The present invention mainly discloses a ratchet wrench, especially a ratchet wrench having a dustproof structure.

Please refer to the patent of "Double Cartridge Reversing Ratchet Wrench" of the Patent No. CN 104227627 A of the People's Republic of China, which is a double-clip reversing ratchet wrench comprising a handle and a wrench body connected at one end of the afterburning rod. The ratchet body is provided with a ratchet wheel perpendicular to the force-applying rod, and a direction switch is arranged at one end of the ratchet toward the force-applying rod, the direction switch comprises a direction handle, and a steering body located below one end of the direction handle and perpendicularly connected with the direction handle, the steering body The side is respectively provided with a latch body, the bottom end of the steering body is provided with a spring hole seat, and a cover plate is arranged on the wrench body at one end of the spring hole seat.

However, the ratchet wrench adopting the above structure, when the cover plate is coupled to the wrench body, may cause a gap between the wrench body and the cover plate more or less due to the tolerance of the production of the parts, and dust in the environment during the work. Or the oil is very easy to enter the ratchet wrench through the gap between the wrench body and the cover plate. If a large amount of dirt accumulates in the ratchet wrench, the card may be stuck and cannot be used any more.

In view of the above-described deficiencies in the conventional structure, the inventors have devised a ratchet wrench having a dustproof structure which overcomes all of the disadvantages of the above-described conventional structure.

The main purpose of the ratchet wrench with dustproof structure of the present invention is to provide a ratchet wrench including a driving device, a dustproof cover and a dustproof oil seal, the driving device is provided with a head at one end, and the head includes a head a first side and a second side, the head is provided with an accommodating hole from the first side to the second side along an axial direction of the virtual through shaft, the head from the second side to the first side A control slot is disposed in a direction parallel to the axial direction of the virtual transoming axis, and the control slot is located on a side of the receiving hole along a radial direction of the virtual transoming shaft, and a driving member is disposed in the head, and one end of the driving member is a driving head is disposed, the driving member is formed with a ring tooth portion radially along the virtual through-axis between the two ends, the ring tooth portion is disposed in the receiving hole, and the driving member is along the virtual tooth portion along the virtual A sealing ring is disposed on each of the two sides of the axially different axial direction, and a control member is disposed in the control slot, and a sealing ring is disposed on the outer periphery of the control member, and the sealing ring is different from the control member One side abuts against the slot of the control slot The inner peripheral edge of the dustproof cover is coupled to the first side of the head and closes a side of the receiving hole adjacent to the first side, and the dustproof cover is provided with a through hole, and the through hole can be provided for the driving component Passing through, the working head protrudes from the surface of the first side, and one of the two sealing rings adjacent to the second side abuts against the head and abutting the first side against the dustproof cover The inner periphery of the through hole is disposed between the driving device and the dustproof cover and simultaneously abuts against the driving device and the dustproof cover. The dustproof sealing ring is disposed on the outer periphery of the dustproof cover. Due to the compressibility of the sealing ring, the cumulative tolerance generated by the combination of the driving member and other components is reduced, and the design of the ratchet wrench disposed between the driving device and the dustproof cover is matched with the seal. The ring and the seal ring can surely achieve the effect of preventing oil from penetrating into the drive unit.

The dustproof cover is recessed adjacent to an outer circumference of one side of the head portion, and a side groove surrounds an outer circumference of the dustproof cover. The dustproof seal is disposed in the side groove.

The receiving portion is provided with a receiving slot and the receiving hole in the axial direction of the first through-side of the virtual cross-axis, and the receiving hole is disposed on the second side of the receiving slot. On the side, the dustproof cover is disposed in the receiving slot.

The dust cover is completely immersed in the pocket.

The dustproof cover is provided with two screw holes, and the dust cover is connected with two screws. The two screws pass through the head from the second side of the head and are respectively screwed to the dust cover. Two screw holes protruding from the side of the dust cover and different from the side of the head and forming a boring head by riveting, the radial width of the boring head being larger than the diameter of the screw hole In the process of avoiding the use of the screw to loosen the seal, the seal is not correct, and the effect of preventing oil stains is lost, and even the parts are detached and cannot be used. When the ratchet wrench needs to be repaired, it is simple to remove the boring head. Easy to disassemble.

The driving device is provided with a virtual reference plane on the surface of the first side, the virtual reference plane is perpendicular to the virtual through-axis, and the distance between the second side and the virtual reference plane forms a thickness, and the control member is convex The distance from one end of the control slot to the virtual reference plane forms a knob height, the knob height is greater than the thickness and the difference between the two is between 0.5 mm and 1.5 mm, so that the control member does not protrude too much The surface of the head prevents the control member from being broken by a foreign object impact.

The driving member is different from the one end of the working head, and a slot is recessed along the virtual coaxial axis. The slot is internally provided with a pressing rod, and the pressing rod has a round rod shape and can be axially opposed to the The driving member slides, and the distance between the end of the pressing rod protruding from the slot to the virtual reference plane forms a button height, the button height is greater than the height of the knob and the difference between the two is less than 1 mm to 2 mm , for the user to quickly find the position of the pressure bar and complete the pressing action, in order to achieve the effect of quick release.

The head is provided with a through hole from the second side to the first side along the axial direction of the virtual through shaft, and the through hole and the receiving hole communicate with each other, and the width of the through hole along the radial direction of the virtual through axis is smaller than the The accommodating hole has a width along the radial direction of the virtual through-axis, and the driving member is provided at an end different from the working head with an annular flange, and the annular flange is inserted into the through hole.

The annular flange protrudes from the surface of the second side, and the distance between the end of the annular flange projecting from the second side to the virtual reference plane forms a flange height, the flange height being greater than the thickness And the difference between the two is between 0.2 mm and 1 mm, and the height of the button is greater than the height of the flange when the pressing rod is not pressed.

The driving device is provided with at least one pattern label, which is marked as a trademark or other pattern, and the pattern label is indicated at one end of the pressing rod protruding from the slot or an end of the control member protruding from the control slot.

The at least one pattern is marked by two numbers, and the two pattern labels are respectively indicated on the pressing rod and the control member.

The driving device is provided with at least one typeface indication, which can be a production history serial number, which is indicated on the side of the dustproof cover adjacent to or different from the head.

The number of the at least one typeface is two, and the two typefaces are respectively marked on opposite sides of the dustproof cover.

The shank is provided with a slanting groove connecting the accommodating hole and the control slot, wherein the slanting groove is provided with a ratchet member, and an elastic member is disposed between the control member and the swaying member. a top member, the control member being capable of controlling the engagement of the ratchet member with the driving member through the elastic member and the top member.

a pressure spring is disposed between the pressure rod and the driving member, and the compression spring is sleeved on the pressing rod, and an end of the pressing rod adjacent to the first side is provided with a top steel ball, and the top steel ball is located at the pressing rod Between the pressure bar and the drive member.

The outer peripheral edge of the receiving hole in the radial direction of the virtual transverse axis does not exceed the range of the outer peripheral edge of the receiving groove along the radial transverse axis.

The receiving hole has a circular hole shape, and the through hole has a circular hole shape, and the dustproof cover plate has a sheet shape.

Other objects, advantages and novel features of the invention will become apparent from the description and appended claims.

The technology, means and functions of the present invention are described in detail with reference to the accompanying drawings.

1 to 4, a perspective view, an exploded perspective view, and a cross-sectional structural view of a ratchet wrench having a dustproof structure according to the present invention. The ratchet wrench 10 of the present invention includes a driving device 20, a dustproof cover 30 and a dustproof oil seal 40; wherein:

One end of the driving device 20 is provided with a head portion 21 including a first side 211 and a second side 212. The head portion 21 is virtualized by the first side 211 toward the second side 212. The accommodating hole 214 is disposed along a side of the accommodating groove 213 adjacent to the second side 212, and the accommodating hole 214 is along the virtual The outer peripheral edge of the radial direction of the transverse axis L does not exceed the range of the outer circumferential edge of the cavity 213 along the radial transverse axis L. The receiving hole 214 has a circular hole shape. The driving device 20 is provided with a virtual reference plane P based on the surface of the first side 211. The virtual reference plane P is perpendicular to the virtual transverse axis L, and the distance between the second side 212 and the virtual reference plane P is formed. A thickness T.

The head 21 is disposed with a through hole 215 in the axial direction of the virtual through-axis L from the second side 212 toward the first side 211. The through hole 215 and the receiving hole 214 are in communication with each other. The radial width of the transverse axis L is smaller than the width of the receiving hole 214 along the radial direction of the virtual transverse axis L, and the through hole 215 has a circular hole shape. The head 21 is provided with a control slot 216 from the second side 212 to the first side 211 in a direction parallel to the axial direction of the virtual coaxial axis L. The control slot 216 is located along the virtual through-axis L of the receiving hole 214. On one side of the radial direction, the head 21 is provided with a ratchet groove 217 that communicates with the receiving hole 214 and the control groove 216.

A driving member 22 is disposed in the head portion 21, and one end of the driving member 22 is provided with a working head 221, and an annular flange 222 is disposed at an end different from the working head 221 and is disposed between the two ends. The traverse portion L is formed in the accommodating hole 214. The working head 221 protrudes from the surface of the first side 211, and the annular flange 222 is inserted. In the perforation 215 and protruding from the surface of the second side 212, the driving device 20 can drive a sleeve-shaped tool head at one end of the head 21, and the driving device 20 is opposite to one end of the head 21 For the user to hold the operation, the annular flange 222 protrudes from the end of the second side 212 to the virtual reference plane P to form a flange height HP, the flange height HP is greater than the thickness T and The difference between the two is between 0.2 mm and 1 mm.

The driving member 22 is different from the end of the working head 221 by a slot 224 extending along the virtual coaxial axis L. The slot 224 is internally provided with a pressing rod 225, and the pressing rod 225 has a round rod shape. And being axially slidable relative to the driving member 22, the pressing rod 225 can control the fixing and releasing state of the tool head on the driving device 20, and the pressing rod 225 protrudes from one end of the slot 224 to the virtual reference The distance between the planes P forms a button height HB which is greater than the flange height HP when the pressure bar 225 is not pressed.

A pressure spring 226 is disposed between the pressing rod 225 and the driving member 22, and the pressing spring 226 is sleeved on the pressing rod 225. The pressing rod 225 is adjacent to one end of the first side 211 and is provided with a top steel ball. 227, the top bead steel ball 227 is located between the pressing rod 225 and the driving member 22, and the user can press the pressing rod 225 to selectively project the top bead steel ball 227 to the driving member 22 to control the tool head assembly. In the fixed and released state of the driving member 22, the compression spring 226 provides a function of automatically resetting the pressing rod 225, and the pressing rod 225 can automatically fix the driving member 22. The driving member 22 is respectively sleeved with a sealing ring 228 on the two sides of the ring gear portion 223 which are different from each other along the axial direction of the virtual coaxial axis L.

A control member 23 is disposed in the control slot 216. The outer periphery of the control member 23 is sleeved with a sealing ring 231. The sealing ring 231 is different from the side of the control member 23 against the slot of the control slot 216. An inner peripheral edge of the mouth, a control member 216 is provided with a ratchet member 24, and an elastic member 25 and a top member 26 are disposed between the control member 23 and the ratchet member 24. The control member 23 The elastic member 25 and the top member 26 can control the engagement manner of the ratchet member 24 to the driving member 22, so that the head portion 21 can selectively drive the driving member 22 clockwise or counterclockwise. The control member 23 protrudes from the end of the control slot 216 to the virtual reference plane P to form a knob height HC. The knob height HC is greater than the thickness T and the difference between the two is between 0.5 mm and 1.5 mm. In the following, the control member 23 does not protrude too much from the surface of the head portion 21, and the control member 23 is prevented from being broken by a foreign object knocking collision, and the button height HB is greater than the knob height HC and the difference between the two. Between 1 mm and 2 mm below, the user can quickly find the pressure Position 225 and the pressing operation is completed, in order to really achieve quick-release effect.

The driving device 20 is provided with at least one pattern designation 27, which can be a trademark or other conspicuous pattern, and the pattern designating mark 27 indicates that the pressing rod 225 protrudes from one end of the slot 224 or the control member 23 protrudes from the One end of the control slot 216, the number of the at least one pattern designation 27 is two in the embodiment, and the two pattern labels 27 are respectively indicated on the pressing rod 225 and the control member 23. The drive unit 20 is provided with at least one typeface designation 28, which can be a production history number.

The dust cover 30 is formed in a sheet shape, and the dust cover 30 is coupled to the first side 211 of the head 21 and closes a side of the receiving hole 214 adjacent to the first side 211. In the receiving pocket 213, the dustproof cover 30 completely immersed in the receiving slot 213. An outer side edge of the dustproof cover 30 adjacent to the side of the head 21 is recessed with a side groove 31 surrounding the outer periphery of the dustproof cover 30.

The dust cover 30 is provided with a through hole 32 and two screw holes 33. The through hole 32 can pass through the driving member 22. One of the two sealing rings 228 adjacent to the second side 212 abuts against The head 21 adjacent to the first side 211 abuts against the inner circumference of the through hole 32 of the dustproof cover 30, and the compressibility of the sealing ring 228 reduces the combination of the driving member 22 and other parts. Cumulative tolerances.

The dust cover 30 is connected with two screws 34. The two screws 34 pass through the head 21 from the second side 212 of the head 21 and are respectively screwed to the two screw holes 33 of the dust cover 30. The screw member 34 protrudes from the side of the dustproof cover plate 30 different from the head portion 21 and is formed by a riveting manner to form a boring head 341 having a radial width greater than the screw hole 33. The aperture is not to be used due to looseness of the screw member 34, and the anti-oil effect is lost, and even the parts are detached and cannot be used. When the ratchet wrench 10 needs to be repaired, the 蕈-shaped head 341 is only required. The erasing can be disassembled in a simple and easy manner. The type designation 28 is indicated on the side of the dust cover 30 adjacent or different from the head 21, and the number of the at least one typeface designation 28 in this embodiment is Two of the two typefaces 28 are respectively indicated on the opposite sides of the dustproof cover 30.

The dust seal 40 is disposed between the driving device 20 and the dustproof cover 30 and simultaneously abuts the driving device 20 and the dustproof cover 30. The dustproof oil seal 40 is received in the side groove 31. The 40 ring is provided on the outer periphery of the dustproof cover 30 and the shape of the dust seal 40 matches the shape of the outer periphery of the dust cover 30.

Since the ratchet wrench 10 is designed such that the dust seal 40 is disposed between the driving device 20 and the dust cover 30, the effect of preventing oil from penetrating into the driving device 20 from the first side 211 of the head 21 can be surely achieved.

As far as the above is concerned, it can be concluded that the present invention has the following advantages:

A ratchet wrench having a dustproof structure according to the present invention, wherein the ratchet wrench includes a driving device, a dustproof cover and a dustproof oil seal, and one end of the driving device is provided with a head, and the head includes a first side And a second side, the head is provided with a receiving hole from the first side to the second side along a direction of a virtual through-axis, the head being parallel to the first side by the second side The control shaft is disposed on a side of the accommodating hole in a radial direction of the accommodating hole, and a driving member is disposed in the head, and one end of the driving member is disposed at one end a driving head, the driving member is formed with a ring tooth portion radially along the virtual through-axis between the two ends, the ring tooth portion is disposed in the receiving hole, and the driving member is along the virtual through-axis axis of the ring gear portion A sealing ring is disposed on each of the opposite sides, and a control member is disposed in the control slot, and a sealing ring is disposed on the outer periphery of the control member, and the sealing ring is different from one side of the control member Dustproof against the inner circumference of the slot of the control slot The plate is coupled to the first side of the head and closes a side of the receiving hole adjacent to the first side, and the dustproof cover is provided with a through hole, the through hole is capable of passing the driving member, the working head Protruding a surface of the first side, wherein one of the two sealing rings adjacent to the second side abuts against the head and adjacent to an inner circumference of the through hole of the dustproof cover The dustproof oil seal is disposed between the driving device and the dustproof cover and simultaneously abuts the driving device and the dustproof cover. The dustproof oil sealing ring is disposed on the outer periphery of the dustproof cover, and the sealing ring is The compressibility reduces the cumulative tolerance generated by the combination of the driving member and other components, and the ratchet wrench is designed to be disposed between the driving device and the dustproof cover, and the sealing ring and the sealing ring are matched. It is possible to surely achieve the effect of preventing oil from penetrating into the driving device.

The above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, so that the numerical value is changed or the equivalent element is replaced, or the equivalent of the scope of the patent application of the present invention. Changes and modifications are still within the scope of the invention patent.

10‧‧‧ Ratchet Wrench
20‧‧‧ drive
21‧‧‧ head
211‧‧‧ first side
212‧‧‧ second side
213‧‧‧ 容容
214‧‧‧ accommodating holes
215‧‧‧Perforation
216‧‧‧Control slot
217‧‧‧thorn groove
22‧‧‧ Drives
221‧‧‧Work head
222‧‧‧ annular flange
223‧‧‧ ring tooth
224‧‧‧ slots
225‧‧‧Press
226‧‧‧pressure spring
227‧‧‧Top steel ball
228‧‧‧Seal ring
23‧‧‧Controls
231‧‧‧ sealing ring
24‧‧‧Spinning pieces
25‧‧‧Flexible parts
26‧‧‧Top conditions
27‧‧‧ pattern marking
28‧‧‧ lettering
30‧‧‧Dust cover
31‧‧‧ side slot
32‧‧‧through hole
33‧‧‧ screw holes
34‧‧‧ screw
341‧‧‧蕈头
40‧‧‧Dustproof oil seal
L‧‧‧ virtual cross shaft
P‧‧‧Virtual datum plane
T‧‧‧ thickness
HP‧‧‧Flange height
HB‧‧‧ button height
HC‧‧‧ knob height

Figure 1 is a perspective view of a ratchet wrench having a dustproof structure according to the present invention. 2 is an exploded perspective view of a ratchet wrench having a dustproof structure according to the present invention. 3 is an exploded perspective view of another perspective view of a ratchet wrench having a dustproof structure according to the present invention. 4 is a cross-sectional structural view of a ratchet wrench having a dustproof structure according to the present invention.

21‧‧‧ head

212‧‧‧ second side

215‧‧‧Perforation

216‧‧‧Control slot

22‧‧‧ Drives

221‧‧‧Work head

222‧‧‧ annular flange

223‧‧‧ ring tooth

224‧‧‧ slots

225‧‧‧Press

226‧‧‧pressure spring

227‧‧‧Top steel ball

228‧‧‧Seal ring

23‧‧‧Controls

231‧‧‧ sealing ring

24‧‧‧Spinning pieces

25‧‧‧Flexible parts

26‧‧‧Top conditions

27‧‧‧ pattern marking

28‧‧‧ lettering

30‧‧‧Dust cover

31‧‧‧ side slot

32‧‧‧through hole

33‧‧‧ screw holes

34‧‧‧ screw

40‧‧‧Dustproof oil seal

Claims (16)

A ratchet wrench with a dustproof structure includes: a driving device, one end of the driving device is provided with a head, the head includes a first side and a second side, the head is from the first side An accommodating hole is disposed on the second side along an axial direction of a virtual through-axis, and the driving device is disposed on the surface of the first side with a virtual reference plane perpendicular to the virtual cross-axis, the virtual reference plane a distance from the second side to the virtual reference plane forms a thickness, and the head is provided with a control slot from the second side to the first side in a direction parallel to the axial direction of the virtual coaxial axis, the control slot is located at the a side of the accommodating hole along the radial direction of the virtual through-axis, wherein the head is provided with a driving member, one end of the driving member is provided with a working head, and the driving member is radially along the virtual transverse axis between the two ends Forming a ring-shaped portion, the ring-shaped portion is disposed in the accommodating hole, and the driving member is respectively sleeved with a sealing ring on the two sides of the ring-shaped portion along the axial direction of the virtual through-axis, wherein the control groove is Equipped with a control unit, the control The outer circumference is sleeved with a sealing ring different from the inner circumference of the control slot at one side of the control member, and the control member protrudes from one end of the control slot to the virtual reference plane The distance between the two forms a knob height, the knob height is greater than the thickness and the difference between the two is between 0.5 mm and 1.5 mm; a dust cover, the dust cover is coupled to the first side of the head and closed The receiving hole is adjacent to a side of the first side, and the dustproof cover is provided with a through hole, wherein the through hole is configured to pass through the driving member, and the working head protrudes from the surface of the first side, the two One of the seal ring adjacent to the second side abuts against the head and is adjacent to the inner periphery of the through hole of the dustproof cover; a dust seal, the dust seal is disposed on the driving device The dustproof cover is simultaneously abutted against the driving device and the dustproof cover, and the dust seal ring is disposed on the outer periphery of the dustproof cover. A ratchet wrench having a dustproof structure according to claim 1, wherein the dustproof cover is recessed with an edge groove adjacent to an outer periphery of one side of the head, the side groove surrounding the outer periphery of the dustproof cover, the dustproof The oil seal is placed in the side groove. The ratchet wrench with a dustproof structure according to claim 2, wherein the head is provided with a receiving slot and the receiving hole from the first side to the second side along the axial direction of the virtual through shaft, The receiving hole is disposed on a side of the receiving groove adjacent to the second side, and the dustproof cover is disposed in the receiving groove. A ratchet wrench having a dustproof structure according to claim 3, wherein the dustproof cover is completely immersed in the receptacle. The ratchet wrench with a dustproof structure according to claim 3, wherein the dustproof cover is provided with two screw holes, the dust cover is connected with two screws, and the two screws are connected by the second side of the head Passing through the head and respectively screwing the two screw holes of the dustproof cover, the screw protrudes from the side of the dust cover and is different from the side of the head, and forms a boring head by riveting. The width of the conical head in the radial direction is greater than the aperture of the screw hole. A ratchet wrench having a dustproof structure according to any one of claims 3 to 5, wherein the driving member is different from the one end of the working head, and a slot is recessed in the virtual coaxial axis. Inserting a pressing rod, the pressing rod is in the shape of a round rod and is axially slidable relative to the driving member, and the pressing rod protrudes from the end of the slot to a distance between the virtual reference plane to form a button height, The height of the button is greater than the height of the knob and the difference between the two is between 1 mm and 2 mm. A ratchet wrench having a dustproof structure according to claim 6, wherein the head is provided with a through hole from the second side toward the first side in the axial direction of the virtual through shaft, and the through hole and the receiving hole are connected to each other Passing, the width of the through hole in the radial direction of the virtual transverse axis is smaller than the width of the receiving hole in the radial direction of the virtual transverse axis The driving member is provided at an end different from the working head with an annular flange, and the annular flange is inserted into the through hole. A ratchet wrench having a dustproof structure according to claim 7, wherein the annular flange protrudes from a surface of the second side, the annular flange protruding from one end of the second side to the virtual reference plane The distance forms a flange height that is greater than the thickness and the difference between the two is between 0.2 mm and 1 mm, and the button height is greater than the flange height when the plunger is not depressed. A ratchet wrench having a dustproof structure according to claim 8, wherein the driving device is provided with at least one pattern designation, the pattern being marked as a trademark or other pattern, the pattern designating the end of the pressing rod protruding from the slot or The control member protrudes from one end of the control slot. A ratchet wrench having a dustproof structure according to claim 9, wherein the at least one pattern is marked by two, and the two pattern labels are respectively indicated on the pressing rod and the control member. A ratchet wrench having a dustproof structure according to claim 8, wherein the driving device is provided with at least one typeface designation, and the typeface indication can be a production history serial number indicating that the dustproof cover is adjacent to or different from the head. On either side of the department. A ratchet wrench having a dustproof structure according to claim 11, wherein the at least one typeface is marked by two, and the two typefaces are respectively indicated on opposite sides of the dustproof cover. The ratchet wrench with a dustproof structure according to claim 8, wherein the head is provided with a ratchet groove that communicates with the receiving hole and the control slot, and the ratchet groove is provided with a ratchet member, and the control is provided. An elastic member and a top member are disposed between the member and the ratchet member, and the control member can control the engagement manner of the ratchet member to the driving member through the elastic member and the top member. A ratchet wrench having a dustproof structure according to claim 13, wherein a pressure spring is disposed between the pressure rod and the driving member, and the compression spring is sleeved on the pressing rod, and the pressing rod is adjacent to the first side. One end of the steel ball is mounted at one end, and the top bead is located between the pressing bar and the driving member. A ratchet wrench having a dustproof structure according to claim 14, wherein an outer circumference of the accommodating hole along a radial direction of the virtual traverse axis does not exceed a range of a radially outer circumference of the accommodating groove along the virtual traverse axis. The ratchet wrench with a dustproof structure according to claim 15, wherein the receiving hole has a circular hole shape, and the through hole has a circular hole shape, and the dustproof cover plate has a sheet shape.