Disclosure of utility model
The first aspect of the present utility model provides a torque limiter, which is used to solve the defect that the torque of a pneumatic wrench cannot be controlled in the prior art, and the torque limiter is used as a power transmission device between the pneumatic wrench and a workpiece, so that the torque limiter can limit the maximum output torque of the pneumatic wrench, can effectively control the torque of the pneumatic wrench, and can avoid the influence of torque out-of-tolerance on the fastening effect.
A second aspect of the utility model provides a torque output tool.
The torque limiting device provided by the utility model comprises:
the input assembly is used for being connected with the torque output end;
The output assembly is used for being connected with a workpiece;
The first torque limiting assembly is provided with a first friction surface and is connected with the input assembly, and the first torque limiting assembly is suitable for rotating under the drive of the input assembly;
The second torque limiting assembly is provided with a second friction surface and is connected with the output assembly, the second friction surface is relatively attached to the first friction surface, and the second torque limiting assembly is suitable for driving the output assembly to rotate under the driving of the first torque limiting assembly.
According to the torque limiting device provided by the utility model, the second torque limiting assembly is sleeved on the output assembly and meshed with the output assembly.
According to the torque limiting device provided by the utility model, the first torque limiting component is sleeved on the output component, the input component is sleeved on the first torque limiting component, and the input component is meshed with the first torque limiting component.
According to the torque limiting device provided by the utility model, the first torque limiting components are provided with a plurality of groups, the second torque limiting components correspond to the first torque limiting components in number, and the first torque limiting components and the second torque limiting components are alternately sleeved on the output components.
According to the torque limiting device provided by the utility model, the output assembly comprises:
the output sleeve is used for being connected with a workpiece;
The gear shaft bolt is connected with the output sleeve and extends along the direction away from the output sleeve, the first torque limiting assembly and the second torque limiting assembly are sleeved on the gear shaft bolt, and the second torque limiting assembly is meshed with the gear shaft bolt;
The pre-tightening nut is arranged at the end part of the gear shaft bolt, which is far away from the output sleeve, and is matched with the output sleeve, so as to limit the fit degree of the first torque limiting assembly and the second torque limiting assembly.
According to the torque limiting device provided by the utility model, the input assembly comprises the input sleeve, a rotating cavity is formed in the input sleeve, and an inner gear matched with the first torque limiting assembly is arranged on the inner wall of the rotating cavity.
The torsion limiting device provided by the utility model further comprises a protective shell, wherein the protective shell is sleeved on the outer sides of the output sleeve and the input sleeve, two ends of the protective shell are respectively abutted against shoulders of the output sleeve and the input sleeve, and the protective shell is used for limiting the movement of the output sleeve and the input sleeve along the axial direction.
According to the torque limiting device provided by the utility model, the first torque limiting assembly comprises one of a metal friction plate and a torque steel plate, and the second torque limiting assembly comprises the other of the metal friction plate and the torque steel plate.
According to the torque limiting device provided by the utility model, the metal friction plate comprises a metal matrix and a friction material layer, and the friction material layer is arranged on at least one side of the metal matrix.
The torque output tool provided by the utility model comprises the torque limiting device.
When the torque limiting device is applied to a twisting process, when the torque reaches a preset threshold, the friction between the first friction surface and the second friction surface can reach the maximum static friction force, and further the first torque limiting component and the second torque limiting component can slide relatively, so that a torque transmission route is interrupted, rotation of the second torque limiting component and the output component can be stopped when the torque reaches the preset threshold, the fastening process is stopped, and the purpose of limiting the torque can be achieved.
Compared with the prior art, when the torque limiting device is used for a pneumatic wrench, the torque limiting device can be used as a power transmission device between the pneumatic wrench and a workpiece, the maximum output torque of the pneumatic wrench is limited through the torque limiting device, the torque of the pneumatic wrench can be effectively controlled, and the influence of the torque out of tolerance on the fastening effect can be avoided.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present utility model more apparent, the technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some embodiments of the present utility model, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.
In describing embodiments of the present application, it should be noted that, unless explicitly stated or limited otherwise, the terms "connected," "connected," and "coupled" should be construed broadly, and may be, for example, fixedly connected, detachably connected, integrally connected, mechanically connected, electrically connected, directly connected, or indirectly connected via an intermediate medium. The specific meaning of the above terms in embodiments of the present application will be understood in detail by those of ordinary skill in the art.
In embodiments of the application, unless expressly specified and limited otherwise, a first feature "up" or "down" on a second feature may be that the first and second features are in direct contact, or that the first and second features are in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the embodiments of the present application. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.
Fig. 1 is an exploded schematic view of a torsion limiting device according to an embodiment of the present utility model, and fig. 2 is a schematic cross-sectional view of a torsion limiting device according to an embodiment of the present utility model.
Referring to fig. 1 and 2, a first aspect of an embodiment of the present utility model provides a torque limiter device 10, where the torque limiter device 10 includes an input assembly 100, an output assembly 200, a first torque limiter assembly and a second torque limiter assembly, the input assembly 100 is used to connect with a torque output end 20, such as an output driving square tenon of a pneumatic wrench, or an output end of a wind mill, etc., and the output assembly 200 is used to connect with a workpiece 30, such as a bolt, a nut, etc., and a fastener, such as a bolt to be fastened is used herein as an example.
The first torque limiting assembly is provided with a first friction surface and is connected with the input assembly 100, the connection mode between the first torque limiting assembly and the input assembly can be clamping connection, fastener connection or key connection and the like, the first torque limiting assembly is suitable for being driven by the input assembly 100 to rotate, the second torque limiting assembly is provided with a second friction surface and is connected with the output assembly 200, the connection mode between the second torque limiting assembly and the output assembly can also be clamping connection, fastener connection or key connection and the like, the second friction surface is relatively attached to the first friction surface, and the second torque limiting assembly is suitable for being driven by the first torque limiting assembly to rotate the output assembly 200.
Specifically, when the torque output end 20 rotates, the input assembly 100 will rotate with it, the input assembly 100 rotates and then carries the first torque limiter assembly to rotate, the first torque limiter assembly and the second torque limiter assembly transmit power through static friction between the first friction surface and the second friction surface, the second torque limiter assembly further rotates with the first torque limiter assembly, the output assembly 200 rotates with the second torque limiter assembly, and finally, the output assembly 200 transmits the rotation torque to the bolt to be fastened, so that the bolt to be fastened rotates to realize fastening.
Referring to fig. 1 and fig. 2, it can be understood that, when the torque limiting device 10 provided in the embodiment of the present utility model is applied in a twisting process, when the torque reaches a preset threshold, the friction between the first friction surface and the second friction surface reaches the maximum static friction force, so that the first torque limiting component and the second torque limiting component slide relatively, and the torque transmission line is interrupted, so that the second torque limiting component and the output component 200 stop rotating when the torque reaches the preset threshold, and the fastening process is terminated, thereby achieving the purpose of limiting the torque.
Compared with the prior art, when the torque limiting device 10 is used for a pneumatic wrench, the torque limiting device 10 can be used as a power transmission device between the pneumatic wrench and the workpiece 30, the maximum output torque of the pneumatic wrench is limited through the torque limiting device 10, the torque of the pneumatic wrench can be effectively controlled, and the influence of the torque out-of-tolerance on the fastening effect can be avoided.
With continued reference to fig. 1 and fig. 2, in an alternative embodiment of the present utility model, the second torque limiting assembly is sleeved on the output assembly 200 and meshed with the output assembly 200, specifically, the second torque limiting assembly has a ring structure, an inner gear is disposed on an inner wall of the second torque limiting assembly, an outer gear corresponding to the inner gear is disposed on the output assembly 200, and power transmission is achieved between the second torque limiting assembly and the output assembly in a manner of meshing between the inner gear and the outer gear.
It will be appreciated that the efficiency of the gearing is typically above 95%, which means that there is less energy loss, and is particularly suitable for high power transmissions, and this arrangement facilitates the use of the torque limiter 10 in high torque environments (up to hundreds of nm or more), and that the wheel transmission is capable of providing a constant transmission ratio, which is important to the torque limiter 10 requiring accurate speed control, and which is effective in improving the control of the maximum torque output by the torque limiter 10 when in use.
In addition, the gear structure has smaller installation space under the same use condition, thereby being beneficial to designing a compact mechanical system, being easy to inspect and maintain and being beneficial to reducing the cost of long-term operation.
With continued reference to fig. 1 and 2, in an alternative embodiment of the present utility model, the first torque limiter is sleeved on the output component 200 and is in running fit with the output component 200, no power is transmitted between the first torque limiter and the output component 200, no power is directly transmitted between the first torque limiter and the output component 200 before the friction between the first friction surface and the second friction surface reaches the maximum static friction force, synchronous rotation is realized between the first torque limiter and the output component 200 through the second torque limiter, and after the friction between the first friction surface and the second friction surface reaches the maximum static friction force, the transmission between the first torque limiter and the second torque limiter fails, at this time, the output component 200 only serves as a rotating shaft of the first torque limiter, the input component 100 is sleeved on the first torque limiter, and the input component 100 is meshed with the first torque limiter.
Specifically, the first torque limiter is also in a ring structure, the outer wall of the first torque limiter is provided with an external gear, the inner wall of the input assembly 100 is provided with an internal gear corresponding to the external gear, power transmission is realized between the external gear and the internal gear in a manner of meshing the internal gear with the external gear, the inner wall of the first torque limiter is a smooth surface so as to be convenient for being in running fit with the output assembly 200, it can be understood that the efficiency of gear transmission is generally more than 95%, which means that energy loss is less, and the torque limiter is especially suitable for high-power transmission, thus the torque limiter 10 is beneficial to use in a high-torque environment (an environment of hundreds of nanometers or more), in addition, the wheel transmission can provide a constant transmission ratio, which is very important for controlling the maximum torque output by the torque limiter 10 when the torque limiter 10 is used, in addition, the gear transmission can bear a larger load, the stability and the safety of the torque limiter 10 in the high-torque environment can be ensured, in addition, the required installation space of the gear structure is smaller under the same using condition, the design is facilitated, the mechanical system is easy to be inspected, and the cost of maintaining is reduced, and the long-term maintenance is beneficial to the mechanical system is maintained.
With continued reference to fig. 1 and 2, in an alternative embodiment of the present utility model, the first torque limiter assembly is provided with a plurality of sets, the second torque limiter assembly corresponds to the number of the first torque limiter assemblies, and the first torque limiter assemblies and the second torque limiter assemblies are alternately sleeved on the output assembly 200, and it is understood that by providing a plurality of sets of the first torque limiter assemblies and the second torque limiter assemblies, in this way, the contact area between the first friction surface and the second friction surface can be greatly increased, so that the stress transmission between the first torque limiting assembly and the second torque limiting assembly is more uniform, the stress in the torque transmission process of the first torque limiting assembly and the second torque limiting assembly can be dispersed, the local stress concentration is reduced, the torque transmission is more stable, and the premature wear or damage caused by the stress concentration is reduced.
In addition, the number of the first torque limiting components and the second torque limiting components can be increased, the maximum torque can be adjusted and controlled more accurately, the actual requirements of different torques can be met, specifically, the contact area between each first friction surface and each second friction surface is increased, more torque adjusting points can be provided, torque control is finer, the torque limiting device 10 can be more flexible, more different application environments can be met, in addition, a redundant design can be provided for alternately installing a plurality of the first torque limiting components and the second torque limiting components, even if a certain first torque limiting component or a certain second torque limiting component breaks down or is damaged, other first torque limiting components and second torque limiting components can still continue to work, and the continuity and reliability of the operation of the torque limiting device 10 can be ensured.
In addition, because the stress of torque transmission is evenly dispersed to the plurality of first torsion limiting assemblies and the plurality of second torsion limiting assemblies, the load born by each single first torsion limiting assembly or second torsion limiting assembly is relatively reduced, so that the service lives of the first torsion limiting assembly and the second torsion limiting assembly can be prolonged, namely the service life of the torsion limiting device 10 is prolonged, and the maintenance cost of the torsion limiting device 10 is reduced.
In addition, the alternate installation of the plurality of first torque limiting assemblies and the second torque limiting assemblies can improve the energy conversion efficiency, because the energy loss in the torque transmission process is dispersed to the plurality of first friction surfaces and the plurality of second friction surfaces, and the concentrated loss of the energy on the single first friction surface or the second friction surface is reduced.
Fig. 3 is an axial schematic view of an output shaft sleeve provided by an embodiment of the present utility model, fig. 4 is a schematic cross-sectional structure of the output shaft sleeve provided by the embodiment of the present utility model, and fig. 5 is an axial schematic view of a gear shaft bolt provided by the embodiment of the present utility model.
Referring to fig. 1 to 5, in an alternative embodiment of the present utility model, an output assembly 200 includes an output socket 210, a gear shaft bolt 220 and a pretension nut 230, one end of the inside of the output socket 210 is provided with an internal gear, the other end is provided with a hexagonal hole as a final torque output for connection with a workpiece 30, the gear shaft bolt 220 is connected with the output socket 210 and extends in a direction away from the output shaft sleeve, a first torque limiting assembly and a second torque limiting assembly are sleeved on the gear shaft bolt 220, the second torque limiting assembly is meshed with the gear shaft bolt 220, in particular, the gear shaft bolt 220 is provided with an external gear, and when installed, the gear shaft bolt 220 is penetrated from the side of the output socket 210 where the hexagonal hole is provided, the external gear of the gear shaft bolt 220 is meshed with the internal gear of the output socket 210, and the first torque limiting assembly and the second torque limiting assembly are alternately installed on the gear shaft bolt 220.
The pre-tightening nut 230 is disposed at an end of the gear shaft bolt 220 away from the output sleeve 210, and the pre-tightening nut 230 is matched with the output sleeve 210 to limit the fitting degree of the first torque limiter and the second torque limiter, in other words, by screwing the pre-tightening nut 230, the first torque limiter and the second torque limiter can be compressed, so as to provide a proper pre-tightening force, that is, set a preset threshold value of torque.
It will be appreciated that the output sleeve 210 is the final element of torque transmission, which receives the torque transmitted from the gear shaft bolt 220 and transmits it to the bolt or nut to be fastened, through the output sleeve 210, the torque of the pneumatic wrench is effectively converted into the fastening force required by the fastener, and in addition, the output sleeve 210 also serves to protect the internal components and support the external load, protect the internal precision components from the external environment, and provide effective structural support for the torque limiter 10.
It will be appreciated that the use of the gear shaft bolt 220 is a key element in the torque transmission path, and compared to the adjustable torque limiter of the prior art, the gear shaft bolt 220 simplifies the structure of the device, reduces additional torque adjustment mechanisms, makes the whole device more compact and lightweight, and can be conveniently used in different situations. The pretension nut 230 applies a pretension force to the first and second torque limiting members by screwing on the external gear of the gear shaft bolt 220, and this pretension force ensures close contact between the first and second torque limiting members, thereby ensuring that a sufficient friction force is generated during torque transmission. In addition, the pre-tightening nut 230 also plays a limiting role, and based on the cooperation with the output sleeve 210, the first torque limiting component and the second torque limiting component can be fixed on the gear shaft bolt 220, so that unexpected relative movement of the first torque limiting component and the second torque limiting component in the torque transmission process is prevented, and the stability and the reliability of torque transmission are ensured. In addition, by adjusting the tightening degree of the pre-tightening nut 230, the pre-tightening force between the first torque limiter and the second torque limiter can be changed, so as to adjust the torque output upper limit of the torque limiter 10, that is, the preset threshold of the torque, and the adjustment mechanism enables the torque limiter 10 to adapt to different torque requirements.
Fig. 6 is a schematic axial side view of an input sleeve according to an embodiment of the present utility model, fig. 7 is a schematic axial side view of the input sleeve according to an embodiment of the present utility model from another perspective, and fig. 8 is a schematic cross-sectional structure of the input sleeve according to an embodiment of the present utility model.
Referring to fig. 1, 2, 6, 7 and 8, in an alternative embodiment of the present utility model, the input assembly 100 includes an input sleeve 110, a driving square hole is provided at the outside of the input sleeve 110, the driving square hole is connected with an output driving square tenon of the pneumatic wrench, as torque input, a rotating cavity 111 is formed in the input sleeve 110, an internal gear matched with the first torque limiting assembly is provided on the inner wall of the rotating cavity 111, and the input sleeve 110 is meshed with an external gear at the outside of the first torque limiting assembly through the internal gear, so as to be used as torque input of the first torque limiting assembly.
Taking a pneumatic wrench as an example, when the torque limiting device 10 is used, an output square tenon of the pneumatic wrench is connected with a square hole on the input sleeve 110, a hexagonal hole arranged on the output sleeve 210 is sleeved with the head of a fastener to be fastened, when the pneumatic wrench is started, torque drives the input sleeve 110, the torque is transmitted to a second torque limiting assembly through a first torque limiting assembly meshed with the input sleeve, and then is transmitted to the gear shaft bolt 220 through the second torque limiting assembly, finally, the torque is transmitted to the fastener through the output sleeve 210 meshed with the gear shaft bolt 220, so that the fastening purpose is achieved, when the fastening torque reaches a preset threshold value, friction between the first torque limiting assembly and the second torque limiting assembly reaches the maximum static friction force, the first torque limiting assembly and the second torque limiting assembly slide relatively, a torque transmission route is interrupted, the gear shaft bolt 220 and the output sleeve 210 stop rotating, and the fastening process is terminated, so that the torque limiting purpose is achieved.
Fig. 9 is a schematic cross-sectional view of a protective housing according to an embodiment of the present utility model.
Referring to fig. 1, 2 and 9, in an alternative embodiment of the present utility model, the torque limiter 10 further includes a protective housing 300, the protective housing 300 is sleeved on the outer sides of the output sleeve 210 and the input sleeve 110, two ends of the protective housing 300 are respectively abutted against the shoulders of the output sleeve 210 and the input sleeve 110, the protective housing 300 is used for limiting the axial movement of the output sleeve 210 and the input sleeve 110, it is understood that the protective housing 300 is used as an external structure of the torque limiter 10, can provide a physical barrier for internal precise components, and can prevent external impact, dust, moisture and other potential damage factors from affecting the internal components, thereby prolonging the service life of the torque limiter 10. In addition, the guard housing 300 may provide structural support to the entire torque limiting device 10 to ensure stability and accurate alignment of the internal components, which may enable efficient and accurate torque transfer. In addition, the presence of the protective housing 300 improves the safety of the torque limiting device 10, prevents accidental removal or flying of internal components, such as the output sleeve 210 or the input sleeve 110, during operation, and protects the safety of the operator.
With continued reference to fig. 1, 2 and 9, an alternative embodiment of the present utility model further includes a circlip 600, and correspondingly, a limiting ring groove is disposed in the end of the protective and limiting housing near the input shaft sleeve, when the protective housing 300 is installed, the protective housing 300 is penetrated from one side of the output sleeve 210, the protective housing 300 is pushed into place by a suitable pressure or tool, and then the circlip 600 is firmly fixed in the limiting ring groove by using a circlip pliers. The retainer 600 is secured depending on its own elasticity and shape of the retainer groove, and when the protective housing 300 is assembled in place, the retainer 600 is compressed and snapped into the retainer groove to form a tight connection, thus preventing movement of the retainer 600.
It will be appreciated that the circlip 600, by virtue of its elastic properties, can be tightly mounted within the retaining ring groove of the guard casing 300, acting as an axial stop, which ensures that the input sleeve 110 is fixed in position axially, preventing it from moving axially during use, thus ensuring the accuracy and stability of torque transmission. In addition, the circlip 600 is relatively simple to install, and can be fixed only by placing the circlip in the limiting ring groove through the circlip pliers, and then the protecting shell 300 is used for fixing the circlip, so that the whole assembly process of the torsion limiting device 10 is simplified, and the assembly efficiency is improved. In addition, since the circlip 600 is removable, it can be individually replaced when worn or damaged, without the need to replace the entire input sleeve 110 or the protective housing 300, which can reduce maintenance costs and downtime.
Fig. 10 is an axial schematic view of a metal friction plate according to an embodiment of the present utility model, and fig. 11 is an axial schematic view of a torque steel plate according to an embodiment of the present utility model.
Referring to fig. 1, 2, 10 and 11, in an alternative embodiment of the present utility model, the first torque limiting assembly includes one of the metal friction plate 400 and the torque steel plate 500, the second torque limiting assembly includes the other of the metal friction plate 400 and the torque steel plate 500, wherein the torque steel plate 500 has a ring structure, when it is coupled with the input sleeve 110 as the first torque limiting assembly, an outer wall of the torque steel plate 500 may be provided with an outer gear coupled with the input sleeve 110, when the torque steel plate 500 is coupled with the gear shaft bolt 220 as the second torque limiting assembly, an inner gear coupled with the gear shaft bolt 220 may be provided at an inner wall of the torque steel plate 500, and a sidewall of the torque steel plate 500 may be used to form the aforementioned first friction surface or second friction surface.
In an alternative embodiment of the present utility model, the metal friction plate 400 includes a metal base 410 and a friction material layer 420, the friction material layer 420 is disposed on at least one side of the metal base 410 for forming the aforementioned first friction surface or second friction surface, the friction material layer 420 may be made of pure metal or powder metallurgy, the metal friction plate 400 has an approximate structure to the torque steel plate 500, and also has a ring structure, when the metal friction plate 400 is matched with the input sleeve 110 as a first torque limiting assembly, the outer wall of the metal base 410 may be provided with an external gear matched with the input sleeve 110, and when the metal friction plate 400 is matched with the gear shaft bolt 220 as a second torque limiting assembly, the inner wall of the metal base 410 may be provided with an internal gear matched with the gear shaft bolt 220, and in particular, may be adaptively set according to practical situations. It will be appreciated that the friction material layer 420 on the metal friction plate 400 can maintain stable friction performance under high load and frequent use conditions, extending the service life of the torque limiter device 10.
Fig. 12 is an application schematic diagram of a torsion limiting device according to an embodiment of the present utility model.
Referring to fig. 12, a second aspect of the embodiment of the present utility model provides a torque output tool, where the torque output tool includes a pneumatic wrench and the torque limiting device 10 according to any of the foregoing embodiments, in use, an output square tenon of the pneumatic wrench is connected with a square hole on the input sleeve 110, a hexagonal hole provided on the output sleeve 210 is sleeved with a fastener head to be fastened, and when the pneumatic wrench is started, the torque drives the input sleeve 110, and the torque is transmitted to the second torque limiting assembly through the first torque limiting assembly engaged with the torque limiting sleeve, and then transmitted to the gear shaft bolt 220 through the second torque limiting assembly, and finally transmitted to the fastener through the output sleeve 210 engaged with the gear shaft bolt 220, so as to achieve the fastening purpose. It can be appreciated that the torque output tool provided in the embodiment of the present utility model, because of including the torque limiter 10 according to any one of the foregoing embodiments, also has the advantages of the torque limiter 10 according to any one of the foregoing embodiments, and the specific advantages can be seen from the foregoing description, and are not repeated herein.
It should be noted that, the technical solutions in the embodiments of the present utility model may be combined with each other, but the basis of the combination is based on that one of ordinary skill in the art can realize the combination, and when the combination of the technical solutions contradicts or cannot be realized, the combination of the technical solutions should be considered as not existing, i.e. not falling within the protection scope of the present utility model.
It should be noted that the above-mentioned embodiments are merely for illustrating the technical solution of the present utility model, and not for limiting the same, and although the present utility model has been described in detail with reference to the above-mentioned embodiments, it should be understood by those skilled in the art that the technical solution described in the above-mentioned embodiments may be modified or some technical features may be equivalently replaced, and these modifications or substitutions do not make the essence of the corresponding technical solution deviate from the spirit and scope of the technical solution of the embodiments of the present utility model.