阅读说明：本技术 一种滚塑机 (Rotational molding machine ) 是由 雷涛 镇方雄 李干明 阮胜 许炎鑫 镇依婷 胡迁逢 镇方超 于 2018-07-26 设计创作，主要内容包括：本发明提供了一种滚塑机,属于机械技术领域。本滚塑机包括控制臂、转轴、转轮和驱动泵,控制臂的两侧分别设置有一旋转体,旋转体包括模具,驱动泵设置在控制臂的外端,转轮外套设有一壳体,壳体固定在控制臂的内端,转轴的中部与转轮固定相连,转轴与壳体之间设置有两个分别位于转轮两侧的出料孔,安装座上设置有若干排料嘴,排料嘴对准排料嘴所在安装座上的模具的外壁面,位于两个安装座上的配料嘴分别与两个出料孔相通,驱动泵向转轮输出高压、高温的液体或气体或液气两相体的热源体；本滚塑机还包括一窑炉,窑炉内固定设置有一回收托盘,两个模具位于回收托盘的上方,转轴横向水平设置。本发明具有能够同时完成两根产品的滚塑等优点。(The invention provides a rotational molding machine, and belongs to the technical field of machinery. The rotational molding machine comprises a control arm, a rotating shaft, a rotating wheel and a driving pump, wherein two sides of the control arm are respectively provided with a rotating body, the rotating body comprises a mold, the driving pump is arranged at the outer end of the control arm, a shell is sleeved outside the rotating wheel and is fixed at the inner end of the control arm, the middle part of the rotating shaft is fixedly connected with the rotating wheel, two discharge holes which are respectively positioned at two sides of the rotating wheel are arranged between the rotating shaft and the shell, a plurality of discharge nozzles are arranged on a mounting seat and are aligned to the outer wall surface of the mold on the mounting seat where the discharge nozzles are positioned, the batching nozzles positioned on the two mounting seats are respectively communicated with the two discharge holes, and the driving pump outputs high-pressure and high-temperature liquid or; the rotational molding machine further comprises a kiln, a recovery tray is fixedly arranged in the kiln, the two molds are located above the recovery tray, and the rotating shaft is horizontally arranged. The invention has the advantages of simultaneously finishing rotational molding of two products and the like.)

1. The utility model provides a rotational molding machine, its characterized in that, this rotational molding machine includes control arm (1), pivot (42), runner (41) and driving pump (2), the both sides of control arm (1) are provided with a rotator respectively, the rotator includes mould (3), driving pump (2) set up the outer end at control arm (1), runner (41) overcoat is equipped with a casing (43), the inner at control arm (1) is fixed in casing (43), the rotator still includes a mount pad (31), two are connected respectively at the both ends of pivot (42) mount pad (31), mould (3) link to each other with corresponding mount pad (31), have feed port (44) that link to each other with the delivery outlet of driving pump (2) on casing (43), the middle part and runner (41) of pivot (42) are fixed to each other, be provided with two discharge openings (45) that are located runner (41) both sides respectively between pivot (42) and casing (43) ) The mounting seat (31) is provided with a plurality of discharge nozzles (56), the discharge nozzles (56) are aligned to the outer wall surface of the die (3) on the mounting seat (31) where the discharge nozzles (56) are positioned, the batching nozzles positioned on the two mounting seats (31) are respectively communicated with the two discharge holes (45), and the driving pump (2) outputs high-pressure and high-temperature liquid or gas or liquid-gas two-phase heat source bodies to the rotating wheel (41); the rotational molding machine further comprises a kiln, a recovery tray is fixedly arranged in the kiln, the two molds (3) are located above the recovery tray, and the rotating shaft (42) is horizontally arranged.

2. The rotational molding machine according to claim 1, wherein a vibration generating device capable of driving the corresponding mounting seat (31) to reciprocate along the axial direction of the rotating shaft (42) is respectively arranged between the rotating shaft (42) and the two mounting seats (31).

3. The rotational molding machine according to claim 2, wherein the vibration generating device comprises a sleeve (46) fixedly connected with the housing (43), the rotating shaft (42) is inserted in the sleeve (46), a sliding valve (47) is sleeved outside the rotating shaft (42), the sliding valve (47) is slidably connected on the rotating shaft (42), the sliding valve (47) is slidably connected with the inner wall of the sleeve (46), a pushing block (48) is sleeved outside the rotating shaft (42), the pushing block (48) is slidably connected outside the rotating shaft (42), the pushing block (48) is fixedly connected with the corresponding mounting seat (31), a limiting block (49) positioned on the inner side of the sliding valve (47) is fixedly arranged on the rotating shaft (42), a first through hole (51) is formed in the sliding valve (47), and two ends of the first through hole (51) respectively penetrate through the inner end surface of the sliding valve (47) and the inner wall surface of the sliding valve (47), a second through hole (52) is formed in the rotating shaft (42), the inner end of the second through hole (52) penetrates through the outer wall surface of the rotating shaft (42), the outer end of the second through hole (52) is communicated with each discharging nozzle (56), and when the slide valve (47) slides towards the outer side of the rotating shaft (42) along the rotating shaft (42), the opening at the outer end of the first through hole (51) can be communicated with the opening at the inner end of the second through hole (52); a first spring seat (53) is arranged on the inner side face of the mounting seat (31), a second spring seat (54) is arranged on the outer end face of the sleeve (46), the first spring seat (53) and the mounting seat (31) and the second spring seat (54) and the sleeve (46) are connected through bearings, and a return spring (55) is connected between the first spring seat (53) and the second spring seat (54).

4. A rotomoulding machine according to claim 1, 2 or 3, wherein a pressure limiting valve is provided at the output of the drive pump (2).

5. A rotomoulding machine as claimed in claim 1, 2 or 3, wherein the mounting base (31) is fixedly provided with a plurality of mounting bars (32) perpendicular to the mounting base (31), and each discharge nozzle (56) is fixed to the mounting bar (32) corresponding to the mounting base (31).

6. A rotomoulding machine as claimed in claim 1, 2 or 3, wherein the heat source is hydraulic oil or steam.

7. A rotomoulding machine according to claim 5, wherein the mould (3) is connected to the respective mounting bars (32) by a plurality of connecting assemblies.

8. The rotational molding machine according to claim 7, wherein the connecting assembly comprises a sliding groove (71) formed in the outer wall surface of the mold (3), the sliding groove (71) is arc-shaped with the radian smaller than 90 degrees, an I-shaped connecting block (72) is slidably connected in the sliding groove (71), one end of the connecting block (72) is matched with the sliding groove (71), a bolt hole (73) is formed in the other end of the connecting block (72), and the connecting block further comprises a connecting bolt (74) connected between the mounting rod (32) and the bolt hole (73).

9. The rotational molding machine according to claim 8, characterized in that two buffer springs (75) are arranged in the sliding chute (71), wherein one end of one buffer spring (75) is connected with one end of the sliding chute (71) in an abutting mode, and the other end of the buffer spring is connected with the connecting block (72); one end of the other buffer spring (75) is connected with the other end of the sliding groove (71) in an abutting mode, and the other end of the other buffer spring is connected with the connecting block (72).

10. A rotomoulding machine according to claim 3, wherein the sleeve (46) is fixedly connected to the control arm (1) by a connecting arm (8).

Technical Field

The invention belongs to the technical field of machinery, and relates to a rotational molding machine.

Background

Rotational molding, also known as rotational molding, rotational molding and the like, is a rotational molding plastic hollow molding method. The method is that plastic raw material is added into a mould, then the mould is continuously rotated along two vertical shafts and heated, the plastic raw material in the mould is gradually and uniformly coated and fused on the whole surface of a mould cavity under the action of gravity and heat energy, and the plastic raw material is formed into a required shape and then is cooled and shaped to form the product.

For rotational molding of products with complex internal structures, dark lattices, irregular pore channels and the like, if rotational molding is carried out by rotating and heating the mold along two vertical shafts, coating blanks of raw materials are inevitably caused, so that the products have defects or can not be rotationally molded into desired plastic parts.

In addition, the existing rotational molding machine adopts a kiln heating mode, the mechanical arm extends into the kiln, and electric/gas components for controlling the rotation of the mold are easy to cause high-temperature failure or damage, so that the rotational molding machine has short service life and poor stability and reliability in the use process.

Disclosure of Invention

The invention aims to solve the problems in the prior art and provide a rotational molding machine, which aims to solve the technical problem of how to simultaneously realize rotational molding of products in two molds, and is reliable and durable.

The purpose of the invention can be realized by the following technical scheme: the rotational molding machine is characterized by comprising a control arm, a rotating shaft, a rotating wheel and a driving pump, wherein two sides of the control arm are respectively provided with a rotating body, the rotating body comprises a mold, the driving pump is arranged at the outer end of the control arm, a shell is sleeved outside the rotating wheel and is fixed at the inner end of the control arm, the rotating body further comprises a mounting seat, two ends of the rotating shaft are respectively connected with two mounting seats, the mold is connected with the corresponding mounting seat, the shell is provided with a feeding hole connected with an output port of the driving pump, the middle part of the rotating shaft is fixedly connected with the rotating wheel, two discharging holes respectively positioned at two sides of the rotating wheel are arranged between the rotating shaft and the shell, the mounting seat is provided with a plurality of discharging nozzles, the discharging nozzles are aligned to the outer wall surface of the mold on the mounting seat where the discharging nozzles are positioned, and the batching nozzles positioned on the two mounting seats are respectively communicated with the two, the driving pump outputs high-pressure and high-temperature liquid or gas or liquid-gas two-phase body to the rotating wheel; the rotational molding machine further comprises a kiln, a recovery tray is fixedly arranged in the kiln, the two molds are located above the recovery tray, and the rotating shaft is horizontally arranged in the transverse direction.

The driving pump drives the heat source body to drive the rotating wheel, the heat source body is sprayed out of the discharging nozzle when the rotating wheel rotates, the mold rotates, the heat source body is sprayed on the outer wall surface of the mold, rotational molding raw materials are loaded into the mold before the rotational molding raw materials are loaded, the control arm is operated, the two rotating bodies are placed in the kiln, the kiln plays a role in auxiliary heating and heat preservation on the mold, the heat source body directly acts on the surface of the mold to heat the mold, and the heat source body is stored in the recovery tray after being sprayed with rain on the mold.

This rotational moulding machine adopts the heat source body drive mould rotatory to carry out the thermal conductance through the heat source body to the mould outer wall, change the rotatory mode of traditional electric control or hydraulic control direct drive mould, simplified the structure greatly, and make the components and parts of going deep into the kiln all belong to mechanical part, do not have the structure that does not have better high temperature resistance performance such as electronic part, make this rotational moulding machine's performance, life, stability in use and reliability promote greatly.

The rotational molding machine adopts a bath heating mode, combines the auxiliary heating and heat preservation effects of a kiln, enables the heating and heat conducting temperatures of the mold to be balanced, and rotational molding products possibly have irregular positions, dead angles and other positions and can be coated well, so that the rotational molding machine is good in molding effect, high in efficiency, high in yield, high in use reliability and high in stability.

In the rotational molding machine, a vibration generating device capable of driving the corresponding mounting seat to reciprocate along the axial direction of the rotating shaft is respectively arranged between the rotating shaft and the two mounting seats.

Because the mould is in the rotation state, and the pivot is horizontal transverse distribution, the better coating in the global of mould of rotational moulding raw materials can be fine, but can not be better to the face and the position of longitudinal distribution such as inboard, outside coat to need one kind can carry out the vibration generating device of horizontal reciprocating motion to the mount pad, make the cloud degree of mould more many, make the rotational moulding raw materials can even coating and extend to each position in the mould.

In the above-mentioned rotational molding machine, the vibration generating device includes a sleeve fixedly connected to the housing, the rotating shaft is inserted in the sleeve, a slide valve is sleeved outside the rotating shaft and is connected on the rotating shaft in a sliding way, the slide valve is connected with the inner wall of the sleeve in a sliding way, the rotating shaft is sleeved with a pushing block, the pushing block is connected outside the rotating shaft in a sliding way, the pushing block is fixedly connected with the corresponding mounting seat, the rotating shaft is fixedly provided with a limiting block positioned at the inner side of the slide valve, the slide valve is provided with a first through hole, two ends of the first through hole respectively penetrate through the inner end surface of the slide valve and the inner wall surface of the slide valve, the rotating shaft is provided with a second through hole, the inner end of the second through hole penetrates through the outer wall surface of the rotating shaft, the outer end of the second through hole is communicated with each discharge nozzle, when the slide valve slides to the outer side of the rotating shaft along the rotating shaft, the outer end opening of the first through hole can be communicated with the inner end opening of the second through hole; the inner side surface of the mounting seat is provided with a first spring seat, the outer end surface of the sleeve is provided with a second spring seat, the first spring seat and the mounting seat and the second spring seat and the sleeve are connected through bearings, and a return spring is connected between the first spring seat and the second spring seat.

In the rotational molding machine, a pressure limiting valve is arranged at the output port of the driving pump.

The heat source body enters the feeding hole from the driving pump and drives the rotating wheel to rotate, the heat source body enters a region between the rotating shaft and the sleeve through the discharging hole, the high-pressure heat source body drives the sliding valve to enable the sliding valve to move outwards on the rotating shaft, the reset spring is extruded, the pressure of the heat source body is gradually increased and pushes the pushing block to enable the mounting seat to move outwards relative to the control arm until the through hole I is communicated with the through hole II, the heat source body can be discharged through the through hole I, the through hole II and the discharging nozzle in sequence, the pressure is reduced after the heat source body is discharged, the mounting seat moves inwards to the original position under the action of the reset spring, and the limiting position is that the sliding valve is abutted against the limiting block.

In the whole process, the pressure of the heat source body is continuously changed, the output pressure of the driving pump is kept constant, the rotating speed of the rotating wheel is irregular, and the running speed of the reciprocating motion of the mounting seat along the axial direction of the rotating shaft is also irregular, so that the rotational molding raw materials in the mold can smoothly reach all parts in the mold to cope with rotational molding of various irregular products.

In the rotational molding machine, the mounting seat is fixedly provided with a plurality of mounting rods perpendicular to the mounting seat, and each discharge nozzle is fixed on the mounting rod corresponding to the mounting seat.

In the rotational molding machine, the heat source body is hydraulic oil or steam.

In the rotational molding machine, the mold is connected with each corresponding mounting rod through a plurality of connecting components.

In foretell rotational moulding machine, coupling assembling is including seting up the spout on the wall outside the mould, the spout is less than 90 degrees arcs for the radian, sliding connection has the connecting block of an I shape in the spout, the one end and the spout cooperation of connecting block, a bolt hole has been seted up to the other end of connecting block, and this connecting block is still including connecting the connecting bolt between installation pole and bolt hole.

Through connecting bolt, the dismouting between realization mould that can be light and the installation pole, moreover, at the irregular rotation process of mount pad always, there is certain relative motion between installation pole and the mould, be the buffering of coping the irregular rotation motion of mould on the one hand, on the other hand improves the continuity of mould rotation process, makes the mould in rotation process intermittent type nature counter rotation or negative acceleration rotatory, is that the rotational moulding raw materials can strike the mould inner wall in the mould, makes each position in the reaching mould that the rotational moulding raw materials can be smooth and easy.

In the rotational molding machine, two buffer springs are arranged in the chute, one end of one buffer spring is connected with one end of the chute in an abutting mode, and the other end of the buffer spring is connected with the connecting block; one end of the other buffer spring is connected with the other end of the sliding groove in an abutting mode, and the other end of the other buffer spring is connected with the connecting block.

The arrangement of the buffer spring can improve the reliability of the whole body, so that the impact abrasion caused by irregular rotation of the die among all parts is small, and the stability of the rotation of the die is improved.

In the rotational molding machine, the sleeve is fixedly connected with the control arm through a connecting arm.

Drawings

Fig. 1 is a schematic view of the whole structure of the rotational molding machine.

Fig. 2 is a schematic structural diagram of a rotating body in the rotational molding machine.

Fig. 3 is a schematic structural view of the vibration generating device in the rotational molding machine.

Fig. 4 is an enlarged view of a portion a in fig. 1.

Figure 5 is a cross-sectional view of the connection assembly in the present rotomolding machine.

In the figure, 1, control arm; 2. driving the pump; 3. a mold; 31. a mounting seat; 32. mounting a rod; 41. a rotating wheel; 42. a rotating shaft; 43. a housing; 44. a feed port; 45. a discharge hole; 46. a sleeve; 47. a spool valve; 48. a pushing block; 49. a limiting block; 51. a first through hole; 52. a second through hole; 53. a first spring seat; 54. a second spring seat; 55. a return spring; 6. a discharge nozzle; 71. a chute; 72. connecting blocks; 73. bolt holes; 74. a connecting bolt; 75. a buffer spring; 8. a connecting arm.

Detailed Description

The following are specific embodiments of the present invention and are further described with reference to the drawings, but the present invention is not limited to these embodiments.

As shown in fig. 1, fig. 2 and fig. 3, the rotational molding machine comprises a control arm 1, a rotating shaft 42, a rotating wheel 41 and a driving pump 2, wherein two sides of the control arm 1 are respectively provided with a rotating body, the rotating body comprises a mold 3, the driving pump 2 is arranged at the outer end of the control arm 1, the rotating wheel 41 is sleeved with a shell 43, the shell 43 is fixed at the inner end of the control arm 1, the rotating body further comprises a mounting seat 31, two ends of the rotating shaft 42 are respectively connected with two mounting seats 31, the mold 3 is connected with the corresponding mounting seats 31, the shell 43 is provided with a feeding hole 44 connected with an output port of the driving pump 2, the middle part of the rotating shaft 42 is fixedly connected with the rotating wheel 41, two discharging holes 45 respectively positioned at two sides of the rotating wheel 41 are arranged between the rotating shaft 42 and the shell 43, the mounting seat 31 is provided with a plurality of discharging nozzles 56, the discharging nozzles 56 are aligned with the outer wall surface of the mold 3 on the mounting seat 31, the driving pump 2 outputs high-pressure and high-temperature liquid or gas or liquid-gas two-phase body to the rotating wheel 41; the rotational molding machine further comprises a kiln, a recovery tray is fixedly arranged in the kiln, the two molds 3 are positioned above the recovery tray, and the rotating shaft 42 is transversely and horizontally arranged.

The driving pump 2 drives the heat source body to drive the rotating wheel 41, the heat source body is sprayed to the discharging nozzle 56 while the rotating wheel 41 rotates, the mould 3 is rotated while the heat source body is sprayed on the outer wall surface of the mould 3, before that, rotational moulding raw materials are loaded into the mould 3, the control arm 1 is operated, two rotating bodies are placed in a kiln, the kiln plays the roles of auxiliary heating and heat preservation on the mould 3, the heat source body directly acts on the surface of the mould 3 to heat the mould, and the heat source body is stored in a recovery tray after being sprayed with rain on the mould 3.

This rotational moulding machine adopts the heat source body drive mould 3 rotatory to carry out the thermal conductance through the heat source body to 3 outer walls of mould, change the rotatory mode of traditional electric control or hydraulic control direct drive mould 3, simplified the structure greatly, and make the components and parts of going deep into the kiln all belong to the mechanical part, do not have the structure that does not have better high temperature resistance performance such as electronic part, make performance, life, stability in use and the reliability of this rotational moulding machine promote greatly.

The rotational molding machine adopts a bath heating mode, combines the auxiliary heating and heat preservation effects of a kiln, enables the heating and heat conducting temperatures of the mold 3 to be balanced, and rotational molding products possibly have irregular positions, dead angles and other positions and can be coated well, so that the rotational molding machine is good in molding effect, high in efficiency, high in yield, high in use reliability and high in stability.

A vibration generating device capable of driving the corresponding mounting seat 31 to reciprocate along the axial direction of the rotating shaft 42 is respectively arranged between the rotating shaft 42 and the two mounting seats 31. Because the mold 3 is in a rotating state, and the rotating shaft 42 is horizontally and transversely distributed, the rotational molding raw material can be well coated on the peripheral surface of the mold 3, but the rotational molding raw material cannot be well coated on the longitudinally distributed plate surfaces and parts such as the inner side and the outer side, and therefore a vibration generating device capable of transversely reciprocating the mounting seat 31 is needed, the cloud degree of the mold 3 is more diversified, and the rotational molding raw material can be uniformly coated and extended to all parts in the mold 3.

As shown in fig. 3 and 4, the vibration generating device includes a sleeve 46 fixedly connected to the housing 43, the rotating shaft 42 is inserted into the sleeve 46, a slide valve 47 is sleeved outside the rotating shaft 42, the slide valve 47 is slidably connected to an inner wall of the sleeve 46, a push block 48 is sleeved outside the rotating shaft 42, the push block 48 is slidably connected to the outside of the rotating shaft 42, the push block 48 is fixedly connected to the corresponding mounting seat 31, a limit block 49 located inside the slide valve 47 is fixedly arranged on the rotating shaft 42, a through hole 51 is formed in the slide valve 47, two ends of the through hole 51 respectively penetrate through an inner end surface of the slide valve 47 and an inner wall surface of the slide valve 47, a through hole two 52 is formed in the rotating shaft 42, inner ends of the through hole two 52 penetrate through an outer wall surface of the rotating shaft 42, outer ends of the through hole two 52 are communicated with each discharge nozzle 56, and when the slide valve 47; the inner side surface of the mounting seat 31 is provided with a first spring seat 53, the outer end surface of the sleeve 46 is provided with a second spring seat 54, the first spring seat 53 and the mounting seat 31 and the second spring seat 54 and the sleeve 46 are connected through bearings, and a return spring 55 is connected between the first spring seat 53 and the second spring seat 54.

A pressure limiting valve is arranged at the output port of the driving pump 2.

The heat source body enters the feeding hole 44 from the driving pump 2, the rotating wheel 41 is driven to rotate, the heat source body enters the area between the rotating shaft 42 and the sleeve 46 through the discharging hole 45, the high-pressure heat source body drives the sliding valve 47, the sliding valve 47 runs outwards on the rotating shaft 42, the return spring 55 is squeezed, the pressure of the heat source body is gradually increased, the pushing block 48 is pushed, the mounting seat 31 runs outwards relative to the control arm 1 until the first through hole 51 is communicated with the second through hole 52, the heat source body can be discharged through the first through hole 51, the second through hole 52 and the discharging nozzle 56 in sequence, the pressure drops after the heat source body is discharged, the mounting seat 31 runs inwards to the original position under the action of the return spring 55, and the limiting position is that the sliding valve 47 abuts against the limiting block 49.

In the whole process, because the pressure of the heat source body is continuously changed, and the output pressure of the driving pump 2 is kept constant, the rotating speed of the rotating wheel 41 is irregular, and the running speed of the reciprocating motion of the mounting seat 31 along the axial direction of the rotating shaft 42 is also irregular, so that the rotational molding raw materials in the mold 3 can smoothly reach all parts in the mold 3 to correspond to rotational molding of various irregular products.

As shown in fig. 1 and fig. 2, a plurality of mounting rods 32 perpendicular to the mounting base 31 are fixedly arranged on the mounting base 31, and each discharge nozzle 56 is fixed on the mounting rod 32 corresponding to the mounting base 31.

The heat source body is hydraulic oil or steam.

As shown in fig. 1, 2 and 5, the mold 3 is connected to each corresponding mounting rod 32 through a plurality of connecting assemblies; coupling assembling is including seting up spout 71 on the mould 3 outer wall surface, and spout 71 is the arc that the radian is less than 90 degrees, and sliding connection has the connecting block 72 of an I shape in spout 71, and the one end and the spout 71 cooperation of connecting block 72, a bolt hole 73 has been seted up to the other end of connecting block 72, and this connecting block is still including connecting the connecting bolt 74 between installation pole 32 and bolt hole 73.

Through connecting bolt 74, the dismouting between realization mould 3 and the installation pole 32 that can be light, moreover, at the irregular rotation process of mount pad 31 always, there is certain relative motion between installation pole 32 and the mould 3, on the one hand is the buffering of reply mould 3 irregular rotation motion, on the other hand improves the continuity of mould 3 rotation process, makes mould 3 in the rotation process intermittent type nature counter-rotation or negative acceleration rotation, is that the rotational moulding raw materials can strike the mould 3 inner wall in mould 3, makes the smooth each position that reaches in the mould 3 of rotational moulding raw materials.

Two buffer springs 75 are arranged in the sliding groove 71, one end of one buffer spring 75 is connected with one end of the sliding groove 71 in an abutting mode, and the other end of the other buffer spring 75 is connected with the connecting block 72; one end of the other buffer spring 75 is connected with the other end of the sliding groove 71 in an abutting mode, and the other end of the other buffer spring is connected with the connecting block 72. The arrangement of the buffer spring 75 can improve the reliability of the whole, so that the impact abrasion caused by irregular rotation of the die 3 among all parts is small, and the stability of the rotation of the die 3 is improved.

The sleeve 46 is fixedly connected with the control arm 1 through a connecting arm 8.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or ambit of the invention as defined in the appended claims.